stm32/can: Factor CAN driver into low-level and Python bindings.

can.c now contains the low-level C interface to the CAN peripheral, and
pyb_can.c the Python-level class/methods/constants.

6 files changed, 867 insertions, 881 deletions

diff --git a/ports/stm32/Makefile b/ports/stm32/Makefile
index 6c0c29572..38540e6d9 100644
--- a/ports/stm32/Makefile
+++ b/ports/stm32/Makefile
@@ -256,6 +256,7 @@ SRC_C = \
 	qspi.c \
 	uart.c \
 	can.c \
+	pyb_can.c \
 	usb.c \
 	wdt.c \
 	eth.c \
diff --git a/ports/stm32/can.c b/ports/stm32/can.c
index 90a3d79a9..371c590a4 100644
--- a/ports/stm32/can.c
+++ b/ports/stm32/can.c
@@ -24,85 +24,43 @@
  * THE SOFTWARE.
  */
 
-#include <stdio.h>
-#include <string.h>
-#include <stdarg.h>
-
-#include "py/objtuple.h"
-#include "py/objarray.h"
 #include "py/runtime.h"
-#include "py/gc.h"
-#include "py/binary.h"
-#include "py/stream.h"
 #include "py/mperrno.h"
 #include "py/mphal.h"
-#include "bufhelper.h"
 #include "can.h"
 #include "irq.h"
 
 #if MICROPY_HW_ENABLE_CAN
 
-#define MASK16 (0)
-#define LIST16 (1)
-#define MASK32 (2)
-#define LIST32 (3)
-
-enum {
-    CAN_STATE_STOPPED,
-    CAN_STATE_ERROR_ACTIVE,
-    CAN_STATE_ERROR_WARNING,
-    CAN_STATE_ERROR_PASSIVE,
-    CAN_STATE_BUS_OFF,
-};
-
-/// \moduleref pyb
-/// \class CAN - controller area network communication bus
-///
-/// CAN implements the standard CAN communications protocol.  At
-/// the physical level it consists of 2 lines: RX and TX.  Note that
-/// to connect the pyboard to a CAN bus you must use a CAN transceiver
-/// to convert the CAN logic signals from the pyboard to the correct
-/// voltage levels on the bus.
-///
-/// Note that this driver does not yet support filter configuration
-/// (it defaults to a single filter that lets through all messages),
-/// or bus timing configuration (except for setting the prescaler).
-///
-/// Example usage (works without anything connected):
-///
-///     from pyb import CAN
-///     can = pyb.CAN(1, pyb.CAN.LOOPBACK)
-///     can.send('message!', 123)   # send message with id 123
-///     can.recv(0)                 # receive message on FIFO 0
-
-typedef enum _rx_state_t {
-    RX_STATE_FIFO_EMPTY = 0,
-    RX_STATE_MESSAGE_PENDING,
-    RX_STATE_FIFO_FULL,
-    RX_STATE_FIFO_OVERFLOW,
-} rx_state_t;
-
-typedef struct _pyb_can_obj_t {
-    mp_obj_base_t base;
-    mp_obj_t rxcallback0;
-    mp_obj_t rxcallback1;
-    mp_uint_t can_id : 8;
-    bool is_enabled : 1;
-    bool extframe : 1;
-    byte rx_state0;
-    byte rx_state1;
-    uint16_t num_error_warning;
-    uint16_t num_error_passive;
-    uint16_t num_bus_off;
-    CAN_HandleTypeDef can;
-} pyb_can_obj_t;
+void can_init0(void) {
+    for (uint i = 0; i < MP_ARRAY_SIZE(MP_STATE_PORT(pyb_can_obj_all)); i++) {
+        MP_STATE_PORT(pyb_can_obj_all)[i] = NULL;
+    }
+}
 
-STATIC mp_obj_t pyb_can_deinit(mp_obj_t self_in);
+void can_deinit_all(void) {
+    for (int i = 0; i < MP_ARRAY_SIZE(MP_STATE_PORT(pyb_can_obj_all)); i++) {
+        pyb_can_obj_t *can_obj = MP_STATE_PORT(pyb_can_obj_all)[i];
+        if (can_obj != NULL) {
+            can_deinit(can_obj);
+        }
+    }
+}
 
-STATIC uint8_t can2_start_bank = 14;
+bool can_init(pyb_can_obj_t *can_obj, uint32_t mode, uint32_t prescaler, uint32_t sjw, uint32_t bs1, uint32_t bs2, bool auto_restart) {
+    CAN_InitTypeDef *init = &can_obj->can.Init;
+    init->Mode = mode << 4; // shift-left so modes fit in a small-int
+    init->Prescaler = prescaler;
+    init->SJW = ((sjw - 1) & 3) << 24;
+    init->BS1 = ((bs1 - 1) & 0xf) << 16;
+    init->BS2 = ((bs2 - 1) & 7) << 20;
+    init->TTCM = DISABLE;
+    init->ABOM = auto_restart ? ENABLE : DISABLE;
+    init->AWUM = DISABLE;
+    init->NART = DISABLE;
+    init->RFLM = DISABLE;
+    init->TXFP = DISABLE;
 
-// assumes Init parameters have been set up correctly
-STATIC bool can_init(pyb_can_obj_t *can_obj) {
     CAN_TypeDef *CANx = NULL;
     uint32_t sce_irq = 0;
     const pin_obj_t *pins[2];
@@ -144,10 +102,10 @@ STATIC bool can_init(pyb_can_obj_t *can_obj) {
     }
 
     // init GPIO
-    uint32_t mode = MP_HAL_PIN_MODE_ALT;
-    uint32_t pull = MP_HAL_PIN_PULL_UP;
+    uint32_t pin_mode = MP_HAL_PIN_MODE_ALT;
+    uint32_t pin_pull = MP_HAL_PIN_PULL_UP;
     for (int i = 0; i < 2; i++) {
-        if (!mp_hal_pin_config_alt(pins[i], mode, pull, AF_FN_CAN, can_obj->can_id)) {
+        if (!mp_hal_pin_config_alt(pins[i], pin_mode, pin_pull, AF_FN_CAN, can_obj->can_id)) {
             return false;
         }
     }
@@ -169,22 +127,38 @@ STATIC bool can_init(pyb_can_obj_t *can_obj) {
     return true;
 }
 
-void can_init0(void) {
-    for (uint i = 0; i < MP_ARRAY_SIZE(MP_STATE_PORT(pyb_can_obj_all)); i++) {
-        MP_STATE_PORT(pyb_can_obj_all)[i] = NULL;
-    }
-}
-
-void can_deinit(void) {
-    for (int i = 0; i < MP_ARRAY_SIZE(MP_STATE_PORT(pyb_can_obj_all)); i++) {
-        pyb_can_obj_t *can_obj = MP_STATE_PORT(pyb_can_obj_all)[i];
-        if (can_obj != NULL) {
-            pyb_can_deinit(MP_OBJ_FROM_PTR(can_obj));
-        }
+void can_deinit(pyb_can_obj_t *self) {
+    self->is_enabled = false;
+    HAL_CAN_DeInit(&self->can);
+    if (self->can.Instance == CAN1) {
+        HAL_NVIC_DisableIRQ(CAN1_RX0_IRQn);
+        HAL_NVIC_DisableIRQ(CAN1_RX1_IRQn);
+        HAL_NVIC_DisableIRQ(CAN1_SCE_IRQn);
+        __HAL_RCC_CAN1_FORCE_RESET();
+        __HAL_RCC_CAN1_RELEASE_RESET();
+        __HAL_RCC_CAN1_CLK_DISABLE();
+    #if defined(CAN2)
+    } else if (self->can.Instance == CAN2) {
+        HAL_NVIC_DisableIRQ(CAN2_RX0_IRQn);
+        HAL_NVIC_DisableIRQ(CAN2_RX1_IRQn);
+        HAL_NVIC_DisableIRQ(CAN2_SCE_IRQn);
+        __HAL_RCC_CAN2_FORCE_RESET();
+        __HAL_RCC_CAN2_RELEASE_RESET();
+        __HAL_RCC_CAN2_CLK_DISABLE();
+    #endif
+    #if defined(CAN3)
+    } else if (self->can.Instance == CAN3) {
+        HAL_NVIC_DisableIRQ(CAN3_RX0_IRQn);
+        HAL_NVIC_DisableIRQ(CAN3_RX1_IRQn);
+        HAL_NVIC_DisableIRQ(CAN3_SCE_IRQn);
+        __HAL_RCC_CAN3_FORCE_RESET();
+        __HAL_RCC_CAN3_RELEASE_RESET();
+        __HAL_RCC_CAN3_CLK_DISABLE();
+    #endif
     }
 }
 
-STATIC void can_clearfilter(uint32_t f) {
+void can_clearfilter(uint32_t f, uint8_t bank) {
     CAN_FilterConfTypeDef filter;
 
     filter.FilterIdHigh         = 0;
@@ -196,12 +170,12 @@ STATIC void can_clearfilter(uint32_t f) {
     filter.FilterMode           = CAN_FILTERMODE_IDMASK;
     filter.FilterScale          = CAN_FILTERSCALE_16BIT;
     filter.FilterActivation     = DISABLE;
-    filter.BankNumber           = can2_start_bank;
+    filter.BankNumber           = bank;
 
     HAL_CAN_ConfigFilter(NULL, &filter);
 }
 
-STATIC int can_receive(CAN_TypeDef *can, int fifo, CanRxMsgTypeDef *msg, uint32_t timeout_ms) {
+int can_receive(CAN_TypeDef *can, int fifo, CanRxMsgTypeDef *msg, uint32_t timeout_ms) {
     volatile uint32_t *rfr;
     if (fifo == CAN_FIFO0) {
         rfr = &can->RF0R;
@@ -247,7 +221,7 @@ STATIC int can_receive(CAN_TypeDef *can, int fifo, CanRxMsgTypeDef *msg, uint32_
 }
 
 // We have our own version of CAN transmit so we can handle Timeout=0 correctly.
-STATIC HAL_StatusTypeDef CAN_Transmit(CAN_HandleTypeDef *hcan, uint32_t Timeout) {
+HAL_StatusTypeDef CAN_Transmit(CAN_HandleTypeDef *hcan, uint32_t Timeout) {
     uint32_t transmitmailbox;
     uint32_t tickstart;
     uint32_t rqcpflag;
@@ -336,704 +310,7 @@ STATIC HAL_StatusTypeDef CAN_Transmit(CAN_HandleTypeDef *hcan, uint32_t Timeout)
     }
 }
 
-/******************************************************************************/
-// MicroPython bindings
-
-STATIC void pyb_can_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
-    pyb_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
-    if (!self->is_enabled) {
-        mp_printf(print, "CAN(%u)", self->can_id);
-    } else {
-        qstr mode;
-        switch (self->can.Init.Mode) {
-            case CAN_MODE_NORMAL: mode = MP_QSTR_NORMAL; break;
-            case CAN_MODE_LOOPBACK: mode = MP_QSTR_LOOPBACK; break;
-            case CAN_MODE_SILENT: mode = MP_QSTR_SILENT; break;
-            case CAN_MODE_SILENT_LOOPBACK: default: mode = MP_QSTR_SILENT_LOOPBACK; break;
-        }
-        mp_printf(print, "CAN(%u, CAN.%q, extframe=%q, auto_restart=%q)",
-            self->can_id,
-            mode,
-            self->extframe ? MP_QSTR_True : MP_QSTR_False,
-            (self->can.Instance->MCR & CAN_MCR_ABOM) ? MP_QSTR_True : MP_QSTR_False);
-    }
-}
-
-// init(mode, extframe=False, prescaler=100, *, sjw=1, bs1=6, bs2=8)
-STATIC mp_obj_t pyb_can_init_helper(pyb_can_obj_t *self, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
-    enum { ARG_mode, ARG_extframe, ARG_prescaler, ARG_sjw, ARG_bs1, ARG_bs2, ARG_auto_restart };
-    static const mp_arg_t allowed_args[] = {
-        { MP_QSTR_mode,         MP_ARG_REQUIRED | MP_ARG_INT,   {.u_int  = CAN_MODE_NORMAL} },
-        { MP_QSTR_extframe,     MP_ARG_BOOL,                    {.u_bool = false} },
-        { MP_QSTR_prescaler,    MP_ARG_INT,                     {.u_int  = 100} },
-        { MP_QSTR_sjw,          MP_ARG_KW_ONLY | MP_ARG_INT,    {.u_int = 1} },
-        { MP_QSTR_bs1,          MP_ARG_KW_ONLY | MP_ARG_INT,    {.u_int = 6} },
-        { MP_QSTR_bs2,          MP_ARG_KW_ONLY | MP_ARG_INT,    {.u_int = 8} },
-        { MP_QSTR_auto_restart, MP_ARG_KW_ONLY | MP_ARG_BOOL,   {.u_bool = false} },
-    };
-
-    // parse args
-    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
-    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
-
-    self->extframe = args[ARG_extframe].u_bool;
-
-    // set the CAN configuration values
-    memset(&self->can, 0, sizeof(self->can));
-    CAN_InitTypeDef *init = &self->can.Init;
-    init->Mode = args[ARG_mode].u_int << 4; // shift-left so modes fit in a small-int
-    init->Prescaler = args[ARG_prescaler].u_int;
-    init->SJW = ((args[ARG_sjw].u_int - 1) & 3) << 24;
-    init->BS1 = ((args[ARG_bs1].u_int - 1) & 0xf) << 16;
-    init->BS2 = ((args[ARG_bs2].u_int - 1) & 7) << 20;
-    init->TTCM = DISABLE;
-    init->ABOM = args[ARG_auto_restart].u_bool ? ENABLE : DISABLE;
-    init->AWUM = DISABLE;
-    init->NART = DISABLE;
-    init->RFLM = DISABLE;
-    init->TXFP = DISABLE;
-
-    // init CAN (if it fails, it's because the port doesn't exist)
-    if (!can_init(self)) {
-        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "CAN(%d) doesn't exist", self->can_id));
-    }
-
-    return mp_const_none;
-}
-
-/// \classmethod \constructor(bus, ...)
-///
-/// Construct a CAN object on the given bus.  `bus` can be 1-2, or 'YA' or 'YB'.
-/// With no additional parameters, the CAN object is created but not
-/// initialised (it has the settings from the last initialisation of
-/// the bus, if any).  If extra arguments are given, the bus is initialised.
-/// See `init` for parameters of initialisation.
-///
-/// The physical pins of the CAN busses are:
-///
-///   - `CAN(1)` is on `YA`: `(RX, TX) = (Y3, Y4) = (PB8, PB9)`
-///   - `CAN(2)` is on `YB`: `(RX, TX) = (Y5, Y6) = (PB12, PB13)`
-STATIC mp_obj_t pyb_can_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
-    // check arguments
-    mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);
-
-    // work out port
-    mp_uint_t can_idx;
-    if (mp_obj_is_str(args[0])) {
-        const char *port = mp_obj_str_get_str(args[0]);
-        if (0) {
-        #ifdef MICROPY_HW_CAN1_NAME
-        } else if (strcmp(port, MICROPY_HW_CAN1_NAME) == 0) {
-            can_idx = PYB_CAN_1;
-        #endif
-        #ifdef MICROPY_HW_CAN2_NAME
-        } else if (strcmp(port, MICROPY_HW_CAN2_NAME) == 0) {
-            can_idx = PYB_CAN_2;
-        #endif
-        #ifdef MICROPY_HW_CAN3_NAME
-        } else if (strcmp(port, MICROPY_HW_CAN3_NAME) == 0) {
-            can_idx = PYB_CAN_3;
-        #endif
-        } else {
-            nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "CAN(%s) doesn't exist", port));
-        }
-    } else {
-        can_idx = mp_obj_get_int(args[0]);
-    }
-    if (can_idx < 1 || can_idx > MP_ARRAY_SIZE(MP_STATE_PORT(pyb_can_obj_all))) {
-        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "CAN(%d) doesn't exist", can_idx));
-    }
-
-    pyb_can_obj_t *self;
-    if (MP_STATE_PORT(pyb_can_obj_all)[can_idx - 1] == NULL) {
-        self = m_new_obj(pyb_can_obj_t);
-        self->base.type = &pyb_can_type;
-        self->can_id = can_idx;
-        self->is_enabled = false;
-        MP_STATE_PORT(pyb_can_obj_all)[can_idx - 1] = self;
-    } else {
-        self = MP_STATE_PORT(pyb_can_obj_all)[can_idx - 1];
-    }
-
-    if (!self->is_enabled || n_args > 1) {
-        if (self->is_enabled) {
-            // The caller is requesting a reconfiguration of the hardware
-            // this can only be done if the hardware is in init mode
-            pyb_can_deinit(MP_OBJ_FROM_PTR(self));
-        }
-
-        self->rxcallback0 = mp_const_none;
-        self->rxcallback1 = mp_const_none;
-        self->rx_state0 = RX_STATE_FIFO_EMPTY;
-        self->rx_state1 = RX_STATE_FIFO_EMPTY;
-
-        if (n_args > 1 || n_kw > 0) {
-            // start the peripheral
-            mp_map_t kw_args;
-            mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);
-            pyb_can_init_helper(self, n_args - 1, args + 1, &kw_args);
-        }
-    }
-
-    return MP_OBJ_FROM_PTR(self);
-}
-
-STATIC mp_obj_t pyb_can_init(size_t n_args, const mp_obj_t *args, mp_map_t *kw_args) {
-    return pyb_can_init_helper(MP_OBJ_TO_PTR(args[0]), n_args - 1, args + 1, kw_args);
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_can_init_obj, 1, pyb_can_init);
-
-/// \method deinit()
-/// Turn off the CAN bus.
-STATIC mp_obj_t pyb_can_deinit(mp_obj_t self_in) {
-    pyb_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
-    self->is_enabled = false;
-    HAL_CAN_DeInit(&self->can);
-    if (self->can.Instance == CAN1) {
-        HAL_NVIC_DisableIRQ(CAN1_RX0_IRQn);
-        HAL_NVIC_DisableIRQ(CAN1_RX1_IRQn);
-        HAL_NVIC_DisableIRQ(CAN1_SCE_IRQn);
-        __HAL_RCC_CAN1_FORCE_RESET();
-        __HAL_RCC_CAN1_RELEASE_RESET();
-        __HAL_RCC_CAN1_CLK_DISABLE();
-    #if defined(CAN2)
-    } else if (self->can.Instance == CAN2) {
-        HAL_NVIC_DisableIRQ(CAN2_RX0_IRQn);
-        HAL_NVIC_DisableIRQ(CAN2_RX1_IRQn);
-        HAL_NVIC_DisableIRQ(CAN2_SCE_IRQn);
-        __HAL_RCC_CAN2_FORCE_RESET();
-        __HAL_RCC_CAN2_RELEASE_RESET();
-        __HAL_RCC_CAN2_CLK_DISABLE();
-    #endif
-    #if defined(CAN3)
-    } else if (self->can.Instance == CAN3) {
-        HAL_NVIC_DisableIRQ(CAN3_RX0_IRQn);
-        HAL_NVIC_DisableIRQ(CAN3_RX1_IRQn);
-        HAL_NVIC_DisableIRQ(CAN3_SCE_IRQn);
-        __HAL_RCC_CAN3_FORCE_RESET();
-        __HAL_RCC_CAN3_RELEASE_RESET();
-        __HAL_RCC_CAN3_CLK_DISABLE();
-    #endif
-    }
-    return mp_const_none;
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_can_deinit_obj, pyb_can_deinit);
-
-// Force a software restart of the controller, to allow transmission after a bus error
-STATIC mp_obj_t pyb_can_restart(mp_obj_t self_in) {
-    pyb_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
-    if (!self->is_enabled) {
-        mp_raise_ValueError(NULL);
-    }
-    CAN_TypeDef *can = self->can.Instance;
-    can->MCR |= CAN_MCR_INRQ;
-    while ((can->MSR & CAN_MSR_INAK) == 0) {
-    }
-    can->MCR &= ~CAN_MCR_INRQ;
-    while ((can->MSR & CAN_MSR_INAK)) {
-    }
-    return mp_const_none;
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_can_restart_obj, pyb_can_restart);
-
-// Get the state of the controller
-STATIC mp_obj_t pyb_can_state(mp_obj_t self_in) {
-    pyb_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
-    mp_int_t state = CAN_STATE_STOPPED;
-    if (self->is_enabled) {
-        CAN_TypeDef *can = self->can.Instance;
-        if (can->ESR & CAN_ESR_BOFF) {
-            state = CAN_STATE_BUS_OFF;
-        } else if (can->ESR & CAN_ESR_EPVF) {
-            state = CAN_STATE_ERROR_PASSIVE;
-        } else if (can->ESR & CAN_ESR_EWGF) {
-            state = CAN_STATE_ERROR_WARNING;
-        } else {
-            state = CAN_STATE_ERROR_ACTIVE;
-        }
-    }
-    return MP_OBJ_NEW_SMALL_INT(state);
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_can_state_obj, pyb_can_state);
-
-// Get info about error states and TX/RX buffers
-STATIC mp_obj_t pyb_can_info(size_t n_args, const mp_obj_t *args) {
-    pyb_can_obj_t *self = MP_OBJ_TO_PTR(args[0]);
-    mp_obj_list_t *list;
-    if (n_args == 1) {
-        list = MP_OBJ_TO_PTR(mp_obj_new_list(8, NULL));
-    } else {
-        if (!mp_obj_is_type(args[1], &mp_type_list)) {
-            mp_raise_TypeError(NULL);
-        }
-        list = MP_OBJ_TO_PTR(args[1]);
-        if (list->len < 8) {
-            mp_raise_ValueError(NULL);
-        }
-    }
-    CAN_TypeDef *can = self->can.Instance;
-    uint32_t esr = can->ESR;
-    list->items[0] = MP_OBJ_NEW_SMALL_INT(esr >> CAN_ESR_TEC_Pos & 0xff);
-    list->items[1] = MP_OBJ_NEW_SMALL_INT(esr >> CAN_ESR_REC_Pos & 0xff);
-    list->items[2] = MP_OBJ_NEW_SMALL_INT(self->num_error_warning);
-    list->items[3] = MP_OBJ_NEW_SMALL_INT(self->num_error_passive);
-    list->items[4] = MP_OBJ_NEW_SMALL_INT(self->num_bus_off);
-    int n_tx_pending = 0x01121223 >> ((can->TSR >> CAN_TSR_TME_Pos & 7) << 2) & 0xf;
-    list->items[5] = MP_OBJ_NEW_SMALL_INT(n_tx_pending);
-    list->items[6] = MP_OBJ_NEW_SMALL_INT(can->RF0R >> CAN_RF0R_FMP0_Pos & 3);
-    list->items[7] = MP_OBJ_NEW_SMALL_INT(can->RF1R >> CAN_RF1R_FMP1_Pos & 3);
-    return MP_OBJ_FROM_PTR(list);
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_can_info_obj, 1, 2, pyb_can_info);
-
-/// \method any(fifo)
-/// Return `True` if any message waiting on the FIFO, else `False`.
-STATIC mp_obj_t pyb_can_any(mp_obj_t self_in, mp_obj_t fifo_in) {
-    pyb_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
-    mp_int_t fifo = mp_obj_get_int(fifo_in);
-    if (fifo == 0) {
-        if (__HAL_CAN_MSG_PENDING(&self->can, CAN_FIFO0) != 0) {
-            return mp_const_true;
-        }
-    } else {
-        if (__HAL_CAN_MSG_PENDING(&self->can, CAN_FIFO1) != 0) {
-            return mp_const_true;
-        }
-    }
-    return mp_const_false;
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_can_any_obj, pyb_can_any);
-
-/// \method send(send, addr, *, timeout=5000)
-/// Send a message on the bus:
-///
-///   - `send` is the data to send (an integer to send, or a buffer object).
-///   - `addr` is the address to send to
-///   - `timeout` is the timeout in milliseconds to wait for the send.
-///
-/// Return value: `None`.
-STATIC mp_obj_t pyb_can_send(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
-    enum { ARG_data, ARG_id, ARG_timeout, ARG_rtr };
-    static const mp_arg_t allowed_args[] = {
-        { MP_QSTR_data,    MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
-        { MP_QSTR_id,      MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
-        { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
-        { MP_QSTR_rtr,     MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = false} },
-    };
-
-    // parse args
-    pyb_can_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
-    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
-    mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
-
-    // get the buffer to send from
-    mp_buffer_info_t bufinfo;
-    uint8_t data[1];
-    pyb_buf_get_for_send(args[ARG_data].u_obj, &bufinfo, data);
-
-    if (bufinfo.len > 8) {
-        mp_raise_ValueError("CAN data field too long");
-    }
-
-    // send the data
-    CanTxMsgTypeDef tx_msg;
-    if (self->extframe) {
-        tx_msg.ExtId = args[ARG_id].u_int & 0x1FFFFFFF;
-        tx_msg.IDE = CAN_ID_EXT;
-    } else {
-        tx_msg.StdId = args[ARG_id].u_int & 0x7FF;
-        tx_msg.IDE = CAN_ID_STD;
-    }
-    if (args[ARG_rtr].u_bool == false) {
-        tx_msg.RTR = CAN_RTR_DATA;
-    } else  {
-        tx_msg.RTR = CAN_RTR_REMOTE;
-    }
-    tx_msg.DLC = bufinfo.len;
-    for (mp_uint_t i = 0; i < bufinfo.len; i++) {
-        tx_msg.Data[i] = ((byte*)bufinfo.buf)[i]; // Data is uint32_t but holds only 1 byte
-    }
-
-    self->can.pTxMsg = &tx_msg;
-    HAL_StatusTypeDef status = CAN_Transmit(&self->can, args[ARG_timeout].u_int);
-
-    if (status != HAL_OK) {
-        mp_hal_raise(status);
-    }
-
-    return mp_const_none;
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_can_send_obj, 1, pyb_can_send);
-
-/// \method recv(fifo, list=None, *, timeout=5000)
-///
-/// Receive data on the bus:
-///
-///   - `fifo` is an integer, which is the FIFO to receive on
-///   - `list` if not None is a list with at least 4 elements
-///   - `timeout` is the timeout in milliseconds to wait for the receive.
-///
-/// Return value: buffer of data bytes.
-STATIC mp_obj_t pyb_can_recv(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
-    enum { ARG_fifo, ARG_list, ARG_timeout };
-    static const mp_arg_t allowed_args[] = {
-        { MP_QSTR_fifo,    MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
-        { MP_QSTR_list,    MP_ARG_OBJ, {.u_rom_obj = MP_ROM_PTR(&mp_const_none_obj)} },
-        { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 5000} },
-    };
-
-    // parse args
-    pyb_can_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
-    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
-    mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
-
-    // receive the data
-    CanRxMsgTypeDef rx_msg;
-    int ret = can_receive(self->can.Instance, args[ARG_fifo].u_int, &rx_msg, args[ARG_timeout].u_int);
-    if (ret < 0) {
-        mp_raise_OSError(-ret);
-    }
-
-    // Manage the rx state machine
-    mp_int_t fifo = args[ARG_fifo].u_int;
-    if ((fifo == CAN_FIFO0 && self->rxcallback0 != mp_const_none) ||
-        (fifo == CAN_FIFO1 && self->rxcallback1 != mp_const_none)) {
-        byte *state = (fifo == CAN_FIFO0) ? &self->rx_state0 : &self->rx_state1;
-
-        switch (*state) {
-        case RX_STATE_FIFO_EMPTY:
-            break;
-        case RX_STATE_MESSAGE_PENDING:
-            if (__HAL_CAN_MSG_PENDING(&self->can, fifo) == 0) {
-                // Fifo is empty
-                __HAL_CAN_ENABLE_IT(&self->can, (fifo == CAN_FIFO0) ? CAN_IT_FMP0 : CAN_IT_FMP1);
-                *state = RX_STATE_FIFO_EMPTY;
-            }
-            break;
-        case RX_STATE_FIFO_FULL:
-            __HAL_CAN_ENABLE_IT(&self->can, (fifo == CAN_FIFO0) ? CAN_IT_FF0 : CAN_IT_FF1);
-            *state = RX_STATE_MESSAGE_PENDING;
-            break;
-        case RX_STATE_FIFO_OVERFLOW:
-            __HAL_CAN_ENABLE_IT(&self->can, (fifo == CAN_FIFO0) ? CAN_IT_FOV0 : CAN_IT_FOV1);
-            __HAL_CAN_ENABLE_IT(&self->can, (fifo == CAN_FIFO0) ? CAN_IT_FF0  : CAN_IT_FF1);
-            *state = RX_STATE_MESSAGE_PENDING;
-            break;
-        }
-    }
-
-    // Create the tuple, or get the list, that will hold the return values
-    // Also populate the fourth element, either a new bytes or reuse existing memoryview
-    mp_obj_t ret_obj = args[ARG_list].u_obj;
-    mp_obj_t *items;
-    if (ret_obj == mp_const_none) {
-        ret_obj = mp_obj_new_tuple(4, NULL);
-        items = ((mp_obj_tuple_t*)MP_OBJ_TO_PTR(ret_obj))->items;
-        items[3] = mp_obj_new_bytes(&rx_msg.Data[0], rx_msg.DLC);
-    } else {
-        // User should provide a list of length at least 4 to hold the values
-        if (!mp_obj_is_type(ret_obj, &mp_type_list)) {
-            mp_raise_TypeError(NULL);
-        }
-        mp_obj_list_t *list = MP_OBJ_TO_PTR(ret_obj);
-        if (list->len < 4) {
-            mp_raise_ValueError(NULL);
-        }
-        items = list->items;
-        // Fourth element must be a memoryview which we assume points to a
-        // byte-like array which is large enough, and then we resize it inplace
-        if (!mp_obj_is_type(items[3], &mp_type_memoryview)) {
-            mp_raise_TypeError(NULL);
-        }
-        mp_obj_array_t *mv = MP_OBJ_TO_PTR(items[3]);
-        if (!(mv->typecode == (MP_OBJ_ARRAY_TYPECODE_FLAG_RW | BYTEARRAY_TYPECODE)
-            || (mv->typecode | 0x20) == (MP_OBJ_ARRAY_TYPECODE_FLAG_RW | 'b'))) {
-            mp_raise_ValueError(NULL);
-        }
-        mv->len = rx_msg.DLC;
-        memcpy(mv->items, &rx_msg.Data[0], rx_msg.DLC);
-    }
-
-    // Populate the first 3 values of the tuple/list
-    if (rx_msg.IDE == CAN_ID_STD) {
-        items[0] = MP_OBJ_NEW_SMALL_INT(rx_msg.StdId);
-    } else {
-        items[0] = MP_OBJ_NEW_SMALL_INT(rx_msg.ExtId);
-    }
-    items[1] = rx_msg.RTR == CAN_RTR_REMOTE ? mp_const_true : mp_const_false;
-    items[2] = MP_OBJ_NEW_SMALL_INT(rx_msg.FMI);
-
-    // Return the result
-    return ret_obj;
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_can_recv_obj, 1, pyb_can_recv);
-
-/// \class method initfilterbanks
-///
-/// Set up the filterbanks. All filter will be disabled and set to their reset states.
-///
-///   - `banks` is an integer that sets how many filter banks that are reserved for CAN1.
-///     0  -> no filters assigned for CAN1
-///     28 -> all filters are assigned to CAN1
-///     CAN2 will get the rest of the 28 available.
-///
-/// Return value: none.
-STATIC mp_obj_t pyb_can_initfilterbanks(mp_obj_t self, mp_obj_t bank_in) {
-    can2_start_bank = mp_obj_get_int(bank_in);
-
-    for (int f = 0; f < 28; f++) {
-        can_clearfilter(f);
-    }
-
-    return mp_const_none;
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_can_initfilterbanks_fun_obj, pyb_can_initfilterbanks);
-STATIC MP_DEFINE_CONST_CLASSMETHOD_OBJ(pyb_can_initfilterbanks_obj, MP_ROM_PTR(&pyb_can_initfilterbanks_fun_obj));
-
-STATIC mp_obj_t pyb_can_clearfilter(mp_obj_t self_in, mp_obj_t bank_in) {
-    pyb_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
-    mp_int_t f = mp_obj_get_int(bank_in);
-    if (self->can_id == 2) {
-        f += can2_start_bank;
-    }
-    can_clearfilter(f);
-    return mp_const_none;
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_can_clearfilter_obj, pyb_can_clearfilter);
-
-/// Configures a filterbank
-/// Return value: `None`.
-#define EXTENDED_ID_TO_16BIT_FILTER(id) (((id & 0xC00000) >> 13) | ((id & 0x38000) >> 15)) | 8
-STATIC mp_obj_t pyb_can_setfilter(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
-    enum { ARG_bank, ARG_mode, ARG_fifo, ARG_params, ARG_rtr };
-    static const mp_arg_t allowed_args[] = {
-        { MP_QSTR_bank,     MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
-        { MP_QSTR_mode,     MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
-        { MP_QSTR_fifo,     MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = CAN_FILTER_FIFO0} },
-        { MP_QSTR_params,   MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
-        { MP_QSTR_rtr,      MP_ARG_KW_ONLY  | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
-    };
-
-    // parse args
-    pyb_can_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
-    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
-    mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
-
-    size_t len;
-    size_t rtr_len;
-    mp_uint_t rtr_masks[4] = {0, 0, 0, 0};
-    mp_obj_t *rtr_flags;
-    mp_obj_t *params;
-    mp_obj_get_array(args[ARG_params].u_obj, &len, &params);
-    if (args[ARG_rtr].u_obj != MP_OBJ_NULL){
-        mp_obj_get_array(args[ARG_rtr].u_obj, &rtr_len, &rtr_flags);
-    }
-
-    CAN_FilterConfTypeDef filter;
-    if (args[ARG_mode].u_int == MASK16 || args[ARG_mode].u_int == LIST16) {
-        if (len != 4) {
-            goto error;
-        }
-        filter.FilterScale = CAN_FILTERSCALE_16BIT;
-        if (self->extframe) {
-            if (args[ARG_rtr].u_obj != MP_OBJ_NULL) {
-                if (args[ARG_mode].u_int == MASK16) {
-                    rtr_masks[0] = mp_obj_get_int(rtr_flags[0]) ? 0x02 : 0;
-                    rtr_masks[1] = 0x02;
-                    rtr_masks[2] = mp_obj_get_int(rtr_flags[1]) ? 0x02 : 0;
-                    rtr_masks[3] = 0x02;
-                } else {  // LIST16
-                    rtr_masks[0] = mp_obj_get_int(rtr_flags[0]) ? 0x02 : 0;
-                    rtr_masks[1] = mp_obj_get_int(rtr_flags[1]) ? 0x02 : 0;
-                    rtr_masks[2] = mp_obj_get_int(rtr_flags[2]) ? 0x02 : 0;
-                    rtr_masks[3] = mp_obj_get_int(rtr_flags[3]) ? 0x02 : 0;
-                }
-            }
-            filter.FilterIdLow      = EXTENDED_ID_TO_16BIT_FILTER(mp_obj_get_int(params[0])) | rtr_masks[0]; // id1
-            filter.FilterMaskIdLow  = EXTENDED_ID_TO_16BIT_FILTER(mp_obj_get_int(params[1])) | rtr_masks[1]; // mask1
-            filter.FilterIdHigh     = EXTENDED_ID_TO_16BIT_FILTER(mp_obj_get_int(params[2])) | rtr_masks[2]; // id2
-            filter.FilterMaskIdHigh = EXTENDED_ID_TO_16BIT_FILTER(mp_obj_get_int(params[3])) | rtr_masks[3]; // mask2
-        } else { // Basic frames
-            if (args[ARG_rtr].u_obj != MP_OBJ_NULL) {
-                if (args[ARG_mode].u_int == MASK16) {
-                    rtr_masks[0] = mp_obj_get_int(rtr_flags[0]) ? 0x10 : 0;
-                    rtr_masks[1] = 0x10;
-                    rtr_masks[2] = mp_obj_get_int(rtr_flags[1]) ? 0x10 : 0;
-                    rtr_masks[3] = 0x10;
-                } else {  // LIST16
-                    rtr_masks[0] = mp_obj_get_int(rtr_flags[0]) ? 0x10 : 0;
-                    rtr_masks[1] = mp_obj_get_int(rtr_flags[1]) ? 0x10 : 0;
-                    rtr_masks[2] = mp_obj_get_int(rtr_flags[2]) ? 0x10 : 0;
-                    rtr_masks[3] = mp_obj_get_int(rtr_flags[3]) ? 0x10 : 0;
-                }
-            }
-            filter.FilterIdLow      = (mp_obj_get_int(params[0]) << 5) | rtr_masks[0]; // id1
-            filter.FilterMaskIdLow  = (mp_obj_get_int(params[1]) << 5) | rtr_masks[1]; // mask1
-            filter.FilterIdHigh     = (mp_obj_get_int(params[2]) << 5) | rtr_masks[2]; // id2
-            filter.FilterMaskIdHigh = (mp_obj_get_int(params[3]) << 5) | rtr_masks[3]; // mask2
-        }
-        if (args[ARG_mode].u_int == MASK16) {
-            filter.FilterMode  = CAN_FILTERMODE_IDMASK;
-        }
-        if (args[ARG_mode].u_int == LIST16) {
-            filter.FilterMode  = CAN_FILTERMODE_IDLIST;
-        }
-    }
-    else if (args[ARG_mode].u_int == MASK32 || args[ARG_mode].u_int == LIST32) {
-        if (len != 2) {
-            goto error;
-        }
-        filter.FilterScale = CAN_FILTERSCALE_32BIT;
-        if (args[ARG_rtr].u_obj != MP_OBJ_NULL) {
-            if (args[ARG_mode].u_int == MASK32) {
-                rtr_masks[0] = mp_obj_get_int(rtr_flags[0]) ? 0x02 : 0;
-                rtr_masks[1] = 0x02;
-            } else {  // LIST32
-                rtr_masks[0] = mp_obj_get_int(rtr_flags[0]) ? 0x02 : 0;
-                rtr_masks[1] = mp_obj_get_int(rtr_flags[1]) ? 0x02 : 0;
-            }
-        }
-        filter.FilterIdHigh     = (mp_obj_get_int(params[0]) & 0x1FFFE000)  >> 13;
-        filter.FilterIdLow      = (((mp_obj_get_int(params[0]) & 0x00001FFF) << 3) | 4) | rtr_masks[0];
-        filter.FilterMaskIdHigh = (mp_obj_get_int(params[1]) & 0x1FFFE000 ) >> 13;
-        filter.FilterMaskIdLow  = (((mp_obj_get_int(params[1]) & 0x00001FFF) << 3) | 4) | rtr_masks[1];
-        if (args[ARG_mode].u_int == MASK32) {
-            filter.FilterMode  = CAN_FILTERMODE_IDMASK;
-        }
-        if (args[ARG_mode].u_int == LIST32) {
-            filter.FilterMode  = CAN_FILTERMODE_IDLIST;
-        }
-    } else {
-        goto error;
-    }
-
-    filter.FilterFIFOAssignment = args[ARG_fifo].u_int;
-    filter.FilterNumber = args[ARG_bank].u_int;
-    if (self->can_id == 1) {
-        if (filter.FilterNumber >= can2_start_bank) {
-            goto error;
-        }
-    } else if (self->can_id == 2) {
-        filter.FilterNumber = filter.FilterNumber + can2_start_bank;
-        if (filter.FilterNumber > 27) {
-            goto error;
-        }
-    } else {
-        if (filter.FilterNumber > 13) { // CAN3 is independant and has its own 14 filters.
-            goto error;
-        }
-    }
-    filter.FilterActivation = ENABLE;
-    filter.BankNumber = can2_start_bank;
-    HAL_CAN_ConfigFilter(&self->can, &filter);
-
-    return mp_const_none;
-
-error:
-    mp_raise_ValueError("CAN filter parameter error");
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_can_setfilter_obj, 1, pyb_can_setfilter);
-
-STATIC mp_obj_t pyb_can_rxcallback(mp_obj_t self_in, mp_obj_t fifo_in, mp_obj_t callback_in) {
-    pyb_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
-    mp_int_t fifo = mp_obj_get_int(fifo_in);
-    mp_obj_t *callback;
-
-    callback = (fifo == 0) ? &self->rxcallback0 : &self->rxcallback1;
-    if (callback_in == mp_const_none) {
-        __HAL_CAN_DISABLE_IT(&self->can, (fifo == 0) ? CAN_IT_FMP0 : CAN_IT_FMP1);
-        __HAL_CAN_DISABLE_IT(&self->can, (fifo == 0) ? CAN_IT_FF0 : CAN_IT_FF1);
-        __HAL_CAN_DISABLE_IT(&self->can, (fifo == 0) ? CAN_IT_FOV0 : CAN_IT_FOV1);
-        __HAL_CAN_CLEAR_FLAG(&self->can, (fifo == CAN_FIFO0) ? CAN_FLAG_FF0 : CAN_FLAG_FF1);
-        __HAL_CAN_CLEAR_FLAG(&self->can, (fifo == CAN_FIFO0) ? CAN_FLAG_FOV0 : CAN_FLAG_FOV1);
-        *callback = mp_const_none;
-    } else if (*callback != mp_const_none) {
-        // Rx call backs has already been initialized
-        // only the callback function should be changed
-        *callback = callback_in;
-    } else if (mp_obj_is_callable(callback_in)) {
-        *callback = callback_in;
-        uint32_t irq = 0;
-        if (self->can_id == PYB_CAN_1) {
-            irq = (fifo == 0) ? CAN1_RX0_IRQn : CAN1_RX1_IRQn;
-        #if defined(CAN2)
-        } else if (self->can_id == PYB_CAN_2) {
-            irq = (fifo == 0) ? CAN2_RX0_IRQn : CAN2_RX1_IRQn;
-        #endif
-        #if defined(CAN3)
-        } else {
-            irq = (fifo == 0) ? CAN3_RX0_IRQn : CAN3_RX1_IRQn;
-        #endif
-        }
-        NVIC_SetPriority(irq, IRQ_PRI_CAN);
-        HAL_NVIC_EnableIRQ(irq);
-        __HAL_CAN_ENABLE_IT(&self->can, (fifo == 0) ? CAN_IT_FMP0 : CAN_IT_FMP1);
-        __HAL_CAN_ENABLE_IT(&self->can, (fifo == 0) ? CAN_IT_FF0  : CAN_IT_FF1);
-        __HAL_CAN_ENABLE_IT(&self->can, (fifo == 0) ? CAN_IT_FOV0 : CAN_IT_FOV1);
-    }
-    return mp_const_none;
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_3(pyb_can_rxcallback_obj, pyb_can_rxcallback);
-
-STATIC const mp_rom_map_elem_t pyb_can_locals_dict_table[] = {
-    // instance methods
-    { MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&pyb_can_init_obj) },
-    { MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&pyb_can_deinit_obj) },
-    { MP_ROM_QSTR(MP_QSTR_restart), MP_ROM_PTR(&pyb_can_restart_obj) },
-    { MP_ROM_QSTR(MP_QSTR_state), MP_ROM_PTR(&pyb_can_state_obj) },
-    { MP_ROM_QSTR(MP_QSTR_info), MP_ROM_PTR(&pyb_can_info_obj) },
-    { MP_ROM_QSTR(MP_QSTR_any), MP_ROM_PTR(&pyb_can_any_obj) },
-    { MP_ROM_QSTR(MP_QSTR_send), MP_ROM_PTR(&pyb_can_send_obj) },
-    { MP_ROM_QSTR(MP_QSTR_recv), MP_ROM_PTR(&pyb_can_recv_obj) },
-    { MP_ROM_QSTR(MP_QSTR_initfilterbanks), MP_ROM_PTR(&pyb_can_initfilterbanks_obj) },
-    { MP_ROM_QSTR(MP_QSTR_setfilter), MP_ROM_PTR(&pyb_can_setfilter_obj) },
-    { MP_ROM_QSTR(MP_QSTR_clearfilter), MP_ROM_PTR(&pyb_can_clearfilter_obj) },
-    { MP_ROM_QSTR(MP_QSTR_rxcallback), MP_ROM_PTR(&pyb_can_rxcallback_obj) },
-
-    // class constants
-    // Note: we use the ST constants >> 4 so they fit in a small-int.  The
-    // right-shift is undone when the constants are used in the init function.
-    { MP_ROM_QSTR(MP_QSTR_NORMAL), MP_ROM_INT(CAN_MODE_NORMAL >> 4) },
-    { MP_ROM_QSTR(MP_QSTR_LOOPBACK), MP_ROM_INT(CAN_MODE_LOOPBACK >> 4) },
-    { MP_ROM_QSTR(MP_QSTR_SILENT), MP_ROM_INT(CAN_MODE_SILENT >> 4) },
-    { MP_ROM_QSTR(MP_QSTR_SILENT_LOOPBACK), MP_ROM_INT(CAN_MODE_SILENT_LOOPBACK >> 4) },
-    { MP_ROM_QSTR(MP_QSTR_MASK16), MP_ROM_INT(MASK16) },
-    { MP_ROM_QSTR(MP_QSTR_LIST16), MP_ROM_INT(LIST16) },
-    { MP_ROM_QSTR(MP_QSTR_MASK32), MP_ROM_INT(MASK32) },
-    { MP_ROM_QSTR(MP_QSTR_LIST32), MP_ROM_INT(LIST32) },
-
-    // values for CAN.state()
-    { MP_ROM_QSTR(MP_QSTR_STOPPED), MP_ROM_INT(CAN_STATE_STOPPED) },
-    { MP_ROM_QSTR(MP_QSTR_ERROR_ACTIVE), MP_ROM_INT(CAN_STATE_ERROR_ACTIVE) },
-    { MP_ROM_QSTR(MP_QSTR_ERROR_WARNING), MP_ROM_INT(CAN_STATE_ERROR_WARNING) },
-    { MP_ROM_QSTR(MP_QSTR_ERROR_PASSIVE), MP_ROM_INT(CAN_STATE_ERROR_PASSIVE) },
-    { MP_ROM_QSTR(MP_QSTR_BUS_OFF), MP_ROM_INT(CAN_STATE_BUS_OFF) },
-};
-
-STATIC MP_DEFINE_CONST_DICT(pyb_can_locals_dict, pyb_can_locals_dict_table);
-
-mp_uint_t can_ioctl(mp_obj_t self_in, mp_uint_t request, uintptr_t arg, int *errcode) {
-    pyb_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
-    mp_uint_t ret;
-    if (request == MP_STREAM_POLL) {
-        uintptr_t flags = arg;
-        ret = 0;
-        if ((flags & MP_STREAM_POLL_RD)
-            && ((__HAL_CAN_MSG_PENDING(&self->can, CAN_FIFO0) != 0)
-                || (__HAL_CAN_MSG_PENDING(&self->can, CAN_FIFO1) != 0))) {
-            ret |= MP_STREAM_POLL_RD;
-        }
-        if ((flags & MP_STREAM_POLL_WR) && (self->can.Instance->TSR & CAN_TSR_TME)) {
-            ret |= MP_STREAM_POLL_WR;
-        }
-    } else {
-        *errcode = MP_EINVAL;
-        ret = -1;
-    }
-    return ret;
-}
-
-void can_rx_irq_handler(uint can_id, uint fifo_id) {
+STATIC void can_rx_irq_handler(uint can_id, uint fifo_id) {
     mp_obj_t callback;
     pyb_can_obj_t *self;
     mp_obj_t irq_reason = MP_OBJ_NEW_SMALL_INT(0);
@@ -1072,25 +349,10 @@ void can_rx_irq_handler(uint can_id, uint fifo_id) {
             break;
     }
 
-    if (callback != mp_const_none) {
-        mp_sched_lock();
-        gc_lock();
-        nlr_buf_t nlr;
-        if (nlr_push(&nlr) == 0) {
-            mp_call_function_2(callback, MP_OBJ_FROM_PTR(self), irq_reason);
-            nlr_pop();
-        } else {
-            // Uncaught exception; disable the callback so it doesn't run again.
-            pyb_can_rxcallback(MP_OBJ_FROM_PTR(self), MP_OBJ_NEW_SMALL_INT(fifo_id), mp_const_none);
-            printf("uncaught exception in CAN(%u) rx interrupt handler\n", self->can_id);
-            mp_obj_print_exception(&mp_plat_print, MP_OBJ_FROM_PTR(nlr.ret_val));
-        }
-        gc_unlock();
-        mp_sched_unlock();
-    }
+    pyb_can_handle_callback(self, fifo_id, callback, irq_reason);
 }
 
-void can_sce_irq_handler(uint can_id) {
+STATIC void can_sce_irq_handler(uint can_id) {
     pyb_can_obj_t *self = MP_STATE_PORT(pyb_can_obj_all)[can_id - 1];
     if (self) {
         self->can.Instance->MSR = CAN_MSR_ERRI;
@@ -1105,20 +367,64 @@ void can_sce_irq_handler(uint can_id) {
     }
 }
 
-STATIC const mp_stream_p_t can_stream_p = {
-    //.read = can_read, // is read sensible for CAN?
-    //.write = can_write, // is write sensible for CAN?
-    .ioctl = can_ioctl,
-    .is_text = false,
-};
+#if defined(MICROPY_HW_CAN1_TX)
+void CAN1_RX0_IRQHandler(void) {
+    IRQ_ENTER(CAN1_RX0_IRQn);
+    can_rx_irq_handler(PYB_CAN_1, CAN_FIFO0);
+    IRQ_EXIT(CAN1_RX0_IRQn);
+}
 
-const mp_obj_type_t pyb_can_type = {
-    { &mp_type_type },
-    .name = MP_QSTR_CAN,
-    .print = pyb_can_print,
-    .make_new = pyb_can_make_new,
-    .protocol = &can_stream_p,
-    .locals_dict = (mp_obj_dict_t*)&pyb_can_locals_dict,
-};
+void CAN1_RX1_IRQHandler(void) {
+    IRQ_ENTER(CAN1_RX1_IRQn);
+    can_rx_irq_handler(PYB_CAN_1, CAN_FIFO1);
+    IRQ_EXIT(CAN1_RX1_IRQn);
+}
+
+void CAN1_SCE_IRQHandler(void) {
+    IRQ_ENTER(CAN1_SCE_IRQn);
+    can_sce_irq_handler(PYB_CAN_1);
+    IRQ_EXIT(CAN1_SCE_IRQn);
+}
+#endif
+
+#if defined(MICROPY_HW_CAN2_TX)
+void CAN2_RX0_IRQHandler(void) {
+    IRQ_ENTER(CAN2_RX0_IRQn);
+    can_rx_irq_handler(PYB_CAN_2, CAN_FIFO0);
+    IRQ_EXIT(CAN2_RX0_IRQn);
+}
+
+void CAN2_RX1_IRQHandler(void) {
+    IRQ_ENTER(CAN2_RX1_IRQn);
+    can_rx_irq_handler(PYB_CAN_2, CAN_FIFO1);
+    IRQ_EXIT(CAN2_RX1_IRQn);
+}
+
+void CAN2_SCE_IRQHandler(void) {
+    IRQ_ENTER(CAN2_SCE_IRQn);
+    can_sce_irq_handler(PYB_CAN_2);
+    IRQ_EXIT(CAN2_SCE_IRQn);
+}
+#endif
+
+#if defined(MICROPY_HW_CAN3_TX)
+void CAN3_RX0_IRQHandler(void) {
+    IRQ_ENTER(CAN3_RX0_IRQn);
+    can_rx_irq_handler(PYB_CAN_3, CAN_FIFO0);
+    IRQ_EXIT(CAN3_RX0_IRQn);
+}
+
+void CAN3_RX1_IRQHandler(void) {
+    IRQ_ENTER(CAN3_RX1_IRQn);
+    can_rx_irq_handler(PYB_CAN_3, CAN_FIFO1);
+    IRQ_EXIT(CAN3_RX1_IRQn);
+}
+
+void CAN3_SCE_IRQHandler(void) {
+    IRQ_ENTER(CAN3_SCE_IRQn);
+    can_sce_irq_handler(PYB_CAN_3);
+    IRQ_EXIT(CAN3_SCE_IRQn);
+}
+#endif
 
 #endif // MICROPY_HW_ENABLE_CAN
diff --git a/ports/stm32/can.h b/ports/stm32/can.h
index ade77acf7..777da7e45 100644
--- a/ports/stm32/can.h
+++ b/ports/stm32/can.h
@@ -26,15 +26,58 @@
 #ifndef MICROPY_INCLUDED_STM32_CAN_H
 #define MICROPY_INCLUDED_STM32_CAN_H
 
+#include "py/obj.h"
+
 #define PYB_CAN_1 (1)
 #define PYB_CAN_2 (2)
 #define PYB_CAN_3 (3)
 
+#define MASK16 (0)
+#define LIST16 (1)
+#define MASK32 (2)
+#define LIST32 (3)
+
+enum {
+    CAN_STATE_STOPPED,
+    CAN_STATE_ERROR_ACTIVE,
+    CAN_STATE_ERROR_WARNING,
+    CAN_STATE_ERROR_PASSIVE,
+    CAN_STATE_BUS_OFF,
+};
+
+typedef enum _rx_state_t {
+    RX_STATE_FIFO_EMPTY = 0,
+    RX_STATE_MESSAGE_PENDING,
+    RX_STATE_FIFO_FULL,
+    RX_STATE_FIFO_OVERFLOW,
+} rx_state_t;
+
+typedef struct _pyb_can_obj_t {
+    mp_obj_base_t base;
+    mp_obj_t rxcallback0;
+    mp_obj_t rxcallback1;
+    mp_uint_t can_id : 8;
+    bool is_enabled : 1;
+    bool extframe : 1;
+    byte rx_state0;
+    byte rx_state1;
+    uint16_t num_error_warning;
+    uint16_t num_error_passive;
+    uint16_t num_bus_off;
+    CAN_HandleTypeDef can;
+} pyb_can_obj_t;
+
 extern const mp_obj_type_t pyb_can_type;
 
 void can_init0(void);
-void can_deinit(void);
-void can_rx_irq_handler(uint can_id, uint fifo_id);
-void can_sce_irq_handler(uint can_id);
+void can_deinit_all(void);
+bool can_init(pyb_can_obj_t *can_obj, uint32_t mode, uint32_t prescaler, uint32_t sjw, uint32_t bs1, uint32_t bs2, bool auto_restart);
+void can_deinit(pyb_can_obj_t *self);
+
+void can_clearfilter(uint32_t f, uint8_t bank);
+int can_receive(CAN_TypeDef *can, int fifo, CanRxMsgTypeDef *msg, uint32_t timeout_ms);
+HAL_StatusTypeDef CAN_Transmit(CAN_HandleTypeDef *hcan, uint32_t Timeout);
+
+void pyb_can_handle_callback(pyb_can_obj_t *self, uint fifo_id, mp_obj_t callback, mp_obj_t irq_reason);
 
 #endif // MICROPY_INCLUDED_STM32_CAN_H
diff --git a/ports/stm32/main.c b/ports/stm32/main.c
index 14ea4e644..93beb0fd7 100644
--- a/ports/stm32/main.c
+++ b/ports/stm32/main.c
@@ -731,7 +731,7 @@ soft_reset_exit:
     timer_deinit();
     uart_deinit_all();
     #if MICROPY_HW_ENABLE_CAN
-    can_deinit();
+    can_deinit_all();
     #endif
     machine_deinit();
 
diff --git a/ports/stm32/pyb_can.c b/ports/stm32/pyb_can.c
new file mode 100644
index 000000000..7aa6dad08
--- /dev/null
+++ b/ports/stm32/pyb_can.c
@@ -0,0 +1,697 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2014-2018 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include "py/objarray.h"
+#include "py/runtime.h"
+#include "py/gc.h"
+#include "py/binary.h"
+#include "py/stream.h"
+#include "py/mperrno.h"
+#include "py/mphal.h"
+#include "bufhelper.h"
+#include "can.h"
+#include "irq.h"
+
+#if MICROPY_HW_ENABLE_CAN
+
+STATIC uint8_t can2_start_bank = 14;
+
+STATIC void pyb_can_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
+    pyb_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    if (!self->is_enabled) {
+        mp_printf(print, "CAN(%u)", self->can_id);
+    } else {
+        qstr mode;
+        switch (self->can.Init.Mode) {
+            case CAN_MODE_NORMAL: mode = MP_QSTR_NORMAL; break;
+            case CAN_MODE_LOOPBACK: mode = MP_QSTR_LOOPBACK; break;
+            case CAN_MODE_SILENT: mode = MP_QSTR_SILENT; break;
+            case CAN_MODE_SILENT_LOOPBACK: default: mode = MP_QSTR_SILENT_LOOPBACK; break;
+        }
+        mp_printf(print, "CAN(%u, CAN.%q, extframe=%q, auto_restart=%q)",
+            self->can_id,
+            mode,
+            self->extframe ? MP_QSTR_True : MP_QSTR_False,
+            (self->can.Instance->MCR & CAN_MCR_ABOM) ? MP_QSTR_True : MP_QSTR_False);
+    }
+}
+
+// init(mode, extframe=False, prescaler=100, *, sjw=1, bs1=6, bs2=8)
+STATIC mp_obj_t pyb_can_init_helper(pyb_can_obj_t *self, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    enum { ARG_mode, ARG_extframe, ARG_prescaler, ARG_sjw, ARG_bs1, ARG_bs2, ARG_auto_restart };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_mode,         MP_ARG_REQUIRED | MP_ARG_INT,   {.u_int  = CAN_MODE_NORMAL} },
+        { MP_QSTR_extframe,     MP_ARG_BOOL,                    {.u_bool = false} },
+        { MP_QSTR_prescaler,    MP_ARG_INT,                     {.u_int  = 100} },
+        { MP_QSTR_sjw,          MP_ARG_KW_ONLY | MP_ARG_INT,    {.u_int = 1} },
+        { MP_QSTR_bs1,          MP_ARG_KW_ONLY | MP_ARG_INT,    {.u_int = 6} },
+        { MP_QSTR_bs2,          MP_ARG_KW_ONLY | MP_ARG_INT,    {.u_int = 8} },
+        { MP_QSTR_auto_restart, MP_ARG_KW_ONLY | MP_ARG_BOOL,   {.u_bool = false} },
+    };
+
+    // parse args
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    self->extframe = args[ARG_extframe].u_bool;
+
+    // set the CAN configuration values
+    memset(&self->can, 0, sizeof(self->can));
+
+    // init CAN (if it fails, it's because the port doesn't exist)
+    if (!can_init(self, args[ARG_mode].u_int, args[ARG_prescaler].u_int, args[ARG_sjw].u_int,
+        args[ARG_bs1].u_int, args[ARG_bs2].u_int, args[ARG_auto_restart].u_bool)) {
+        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "CAN(%d) doesn't exist", self->can_id));
+    }
+
+    return mp_const_none;
+}
+
+// CAN(bus, ...)
+STATIC mp_obj_t pyb_can_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
+    // check arguments
+    mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);
+
+    // work out port
+    mp_uint_t can_idx;
+    if (mp_obj_is_str(args[0])) {
+        const char *port = mp_obj_str_get_str(args[0]);
+        if (0) {
+        #ifdef MICROPY_HW_CAN1_NAME
+        } else if (strcmp(port, MICROPY_HW_CAN1_NAME) == 0) {
+            can_idx = PYB_CAN_1;
+        #endif
+        #ifdef MICROPY_HW_CAN2_NAME
+        } else if (strcmp(port, MICROPY_HW_CAN2_NAME) == 0) {
+            can_idx = PYB_CAN_2;
+        #endif
+        #ifdef MICROPY_HW_CAN3_NAME
+        } else if (strcmp(port, MICROPY_HW_CAN3_NAME) == 0) {
+            can_idx = PYB_CAN_3;
+        #endif
+        } else {
+            nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "CAN(%s) doesn't exist", port));
+        }
+    } else {
+        can_idx = mp_obj_get_int(args[0]);
+    }
+    if (can_idx < 1 || can_idx > MP_ARRAY_SIZE(MP_STATE_PORT(pyb_can_obj_all))) {
+        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "CAN(%d) doesn't exist", can_idx));
+    }
+
+    pyb_can_obj_t *self;
+    if (MP_STATE_PORT(pyb_can_obj_all)[can_idx - 1] == NULL) {
+        self = m_new_obj(pyb_can_obj_t);
+        self->base.type = &pyb_can_type;
+        self->can_id = can_idx;
+        self->is_enabled = false;
+        MP_STATE_PORT(pyb_can_obj_all)[can_idx - 1] = self;
+    } else {
+        self = MP_STATE_PORT(pyb_can_obj_all)[can_idx - 1];
+    }
+
+    if (!self->is_enabled || n_args > 1) {
+        if (self->is_enabled) {
+            // The caller is requesting a reconfiguration of the hardware
+            // this can only be done if the hardware is in init mode
+            can_deinit(self);
+        }
+
+        self->rxcallback0 = mp_const_none;
+        self->rxcallback1 = mp_const_none;
+        self->rx_state0 = RX_STATE_FIFO_EMPTY;
+        self->rx_state1 = RX_STATE_FIFO_EMPTY;
+
+        if (n_args > 1 || n_kw > 0) {
+            // start the peripheral
+            mp_map_t kw_args;
+            mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);
+            pyb_can_init_helper(self, n_args - 1, args + 1, &kw_args);
+        }
+    }
+
+    return MP_OBJ_FROM_PTR(self);
+}
+
+STATIC mp_obj_t pyb_can_init(size_t n_args, const mp_obj_t *args, mp_map_t *kw_args) {
+    return pyb_can_init_helper(MP_OBJ_TO_PTR(args[0]), n_args - 1, args + 1, kw_args);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_can_init_obj, 1, pyb_can_init);
+
+// deinit()
+STATIC mp_obj_t pyb_can_deinit(mp_obj_t self_in) {
+    pyb_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    can_deinit(self);
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_can_deinit_obj, pyb_can_deinit);
+
+// Force a software restart of the controller, to allow transmission after a bus error
+STATIC mp_obj_t pyb_can_restart(mp_obj_t self_in) {
+    pyb_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    if (!self->is_enabled) {
+        mp_raise_ValueError(NULL);
+    }
+    CAN_TypeDef *can = self->can.Instance;
+    can->MCR |= CAN_MCR_INRQ;
+    while ((can->MSR & CAN_MSR_INAK) == 0) {
+    }
+    can->MCR &= ~CAN_MCR_INRQ;
+    while ((can->MSR & CAN_MSR_INAK)) {
+    }
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_can_restart_obj, pyb_can_restart);
+
+// Get the state of the controller
+STATIC mp_obj_t pyb_can_state(mp_obj_t self_in) {
+    pyb_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_int_t state = CAN_STATE_STOPPED;
+    if (self->is_enabled) {
+        CAN_TypeDef *can = self->can.Instance;
+        if (can->ESR & CAN_ESR_BOFF) {
+            state = CAN_STATE_BUS_OFF;
+        } else if (can->ESR & CAN_ESR_EPVF) {
+            state = CAN_STATE_ERROR_PASSIVE;
+        } else if (can->ESR & CAN_ESR_EWGF) {
+            state = CAN_STATE_ERROR_WARNING;
+        } else {
+            state = CAN_STATE_ERROR_ACTIVE;
+        }
+    }
+    return MP_OBJ_NEW_SMALL_INT(state);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_can_state_obj, pyb_can_state);
+
+// Get info about error states and TX/RX buffers
+STATIC mp_obj_t pyb_can_info(size_t n_args, const mp_obj_t *args) {
+    pyb_can_obj_t *self = MP_OBJ_TO_PTR(args[0]);
+    mp_obj_list_t *list;
+    if (n_args == 1) {
+        list = MP_OBJ_TO_PTR(mp_obj_new_list(8, NULL));
+    } else {
+        if (!mp_obj_is_type(args[1], &mp_type_list)) {
+            mp_raise_TypeError(NULL);
+        }
+        list = MP_OBJ_TO_PTR(args[1]);
+        if (list->len < 8) {
+            mp_raise_ValueError(NULL);
+        }
+    }
+    CAN_TypeDef *can = self->can.Instance;
+    uint32_t esr = can->ESR;
+    list->items[0] = MP_OBJ_NEW_SMALL_INT(esr >> CAN_ESR_TEC_Pos & 0xff);
+    list->items[1] = MP_OBJ_NEW_SMALL_INT(esr >> CAN_ESR_REC_Pos & 0xff);
+    list->items[2] = MP_OBJ_NEW_SMALL_INT(self->num_error_warning);
+    list->items[3] = MP_OBJ_NEW_SMALL_INT(self->num_error_passive);
+    list->items[4] = MP_OBJ_NEW_SMALL_INT(self->num_bus_off);
+    int n_tx_pending = 0x01121223 >> ((can->TSR >> CAN_TSR_TME_Pos & 7) << 2) & 0xf;
+    list->items[5] = MP_OBJ_NEW_SMALL_INT(n_tx_pending);
+    list->items[6] = MP_OBJ_NEW_SMALL_INT(can->RF0R >> CAN_RF0R_FMP0_Pos & 3);
+    list->items[7] = MP_OBJ_NEW_SMALL_INT(can->RF1R >> CAN_RF1R_FMP1_Pos & 3);
+    return MP_OBJ_FROM_PTR(list);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_can_info_obj, 1, 2, pyb_can_info);
+
+// any(fifo) - return `True` if any message waiting on the FIFO, else `False`
+STATIC mp_obj_t pyb_can_any(mp_obj_t self_in, mp_obj_t fifo_in) {
+    pyb_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_int_t fifo = mp_obj_get_int(fifo_in);
+    if (fifo == 0) {
+        if (__HAL_CAN_MSG_PENDING(&self->can, CAN_FIFO0) != 0) {
+            return mp_const_true;
+        }
+    } else {
+        if (__HAL_CAN_MSG_PENDING(&self->can, CAN_FIFO1) != 0) {
+            return mp_const_true;
+        }
+    }
+    return mp_const_false;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_can_any_obj, pyb_can_any);
+
+// send(send, addr, *, timeout=5000)
+STATIC mp_obj_t pyb_can_send(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    enum { ARG_data, ARG_id, ARG_timeout, ARG_rtr };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_data,    MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
+        { MP_QSTR_id,      MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
+        { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
+        { MP_QSTR_rtr,     MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = false} },
+    };
+
+    // parse args
+    pyb_can_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    // get the buffer to send from
+    mp_buffer_info_t bufinfo;
+    uint8_t data[1];
+    pyb_buf_get_for_send(args[ARG_data].u_obj, &bufinfo, data);
+
+    if (bufinfo.len > 8) {
+        mp_raise_ValueError("CAN data field too long");
+    }
+
+    // send the data
+    CanTxMsgTypeDef tx_msg;
+    if (self->extframe) {
+        tx_msg.ExtId = args[ARG_id].u_int & 0x1FFFFFFF;
+        tx_msg.IDE = CAN_ID_EXT;
+    } else {
+        tx_msg.StdId = args[ARG_id].u_int & 0x7FF;
+        tx_msg.IDE = CAN_ID_STD;
+    }
+    if (args[ARG_rtr].u_bool == false) {
+        tx_msg.RTR = CAN_RTR_DATA;
+    } else  {
+        tx_msg.RTR = CAN_RTR_REMOTE;
+    }
+    tx_msg.DLC = bufinfo.len;
+    for (mp_uint_t i = 0; i < bufinfo.len; i++) {
+        tx_msg.Data[i] = ((byte*)bufinfo.buf)[i]; // Data is uint32_t but holds only 1 byte
+    }
+
+    self->can.pTxMsg = &tx_msg;
+    HAL_StatusTypeDef status = CAN_Transmit(&self->can, args[ARG_timeout].u_int);
+
+    if (status != HAL_OK) {
+        mp_hal_raise(status);
+    }
+
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_can_send_obj, 1, pyb_can_send);
+
+// recv(fifo, list=None, *, timeout=5000)
+STATIC mp_obj_t pyb_can_recv(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    enum { ARG_fifo, ARG_list, ARG_timeout };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_fifo,    MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
+        { MP_QSTR_list,    MP_ARG_OBJ, {.u_rom_obj = MP_ROM_PTR(&mp_const_none_obj)} },
+        { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 5000} },
+    };
+
+    // parse args
+    pyb_can_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    // receive the data
+    CanRxMsgTypeDef rx_msg;
+    int ret = can_receive(self->can.Instance, args[ARG_fifo].u_int, &rx_msg, args[ARG_timeout].u_int);
+    if (ret < 0) {
+        mp_raise_OSError(-ret);
+    }
+
+    // Manage the rx state machine
+    mp_int_t fifo = args[ARG_fifo].u_int;
+    if ((fifo == CAN_FIFO0 && self->rxcallback0 != mp_const_none) ||
+        (fifo == CAN_FIFO1 && self->rxcallback1 != mp_const_none)) {
+        byte *state = (fifo == CAN_FIFO0) ? &self->rx_state0 : &self->rx_state1;
+
+        switch (*state) {
+        case RX_STATE_FIFO_EMPTY:
+            break;
+        case RX_STATE_MESSAGE_PENDING:
+            if (__HAL_CAN_MSG_PENDING(&self->can, fifo) == 0) {
+                // Fifo is empty
+                __HAL_CAN_ENABLE_IT(&self->can, (fifo == CAN_FIFO0) ? CAN_IT_FMP0 : CAN_IT_FMP1);
+                *state = RX_STATE_FIFO_EMPTY;
+            }
+            break;
+        case RX_STATE_FIFO_FULL:
+            __HAL_CAN_ENABLE_IT(&self->can, (fifo == CAN_FIFO0) ? CAN_IT_FF0 : CAN_IT_FF1);
+            *state = RX_STATE_MESSAGE_PENDING;
+            break;
+        case RX_STATE_FIFO_OVERFLOW:
+            __HAL_CAN_ENABLE_IT(&self->can, (fifo == CAN_FIFO0) ? CAN_IT_FOV0 : CAN_IT_FOV1);
+            __HAL_CAN_ENABLE_IT(&self->can, (fifo == CAN_FIFO0) ? CAN_IT_FF0  : CAN_IT_FF1);
+            *state = RX_STATE_MESSAGE_PENDING;
+            break;
+        }
+    }
+
+    // Create the tuple, or get the list, that will hold the return values
+    // Also populate the fourth element, either a new bytes or reuse existing memoryview
+    mp_obj_t ret_obj = args[ARG_list].u_obj;
+    mp_obj_t *items;
+    if (ret_obj == mp_const_none) {
+        ret_obj = mp_obj_new_tuple(4, NULL);
+        items = ((mp_obj_tuple_t*)MP_OBJ_TO_PTR(ret_obj))->items;
+        items[3] = mp_obj_new_bytes(&rx_msg.Data[0], rx_msg.DLC);
+    } else {
+        // User should provide a list of length at least 4 to hold the values
+        if (!mp_obj_is_type(ret_obj, &mp_type_list)) {
+            mp_raise_TypeError(NULL);
+        }
+        mp_obj_list_t *list = MP_OBJ_TO_PTR(ret_obj);
+        if (list->len < 4) {
+            mp_raise_ValueError(NULL);
+        }
+        items = list->items;
+        // Fourth element must be a memoryview which we assume points to a
+        // byte-like array which is large enough, and then we resize it inplace
+        if (!mp_obj_is_type(items[3], &mp_type_memoryview)) {
+            mp_raise_TypeError(NULL);
+        }
+        mp_obj_array_t *mv = MP_OBJ_TO_PTR(items[3]);
+        if (!(mv->typecode == (MP_OBJ_ARRAY_TYPECODE_FLAG_RW | BYTEARRAY_TYPECODE)
+            || (mv->typecode | 0x20) == (MP_OBJ_ARRAY_TYPECODE_FLAG_RW | 'b'))) {
+            mp_raise_ValueError(NULL);
+        }
+        mv->len = rx_msg.DLC;
+        memcpy(mv->items, &rx_msg.Data[0], rx_msg.DLC);
+    }
+
+    // Populate the first 3 values of the tuple/list
+    if (rx_msg.IDE == CAN_ID_STD) {
+        items[0] = MP_OBJ_NEW_SMALL_INT(rx_msg.StdId);
+    } else {
+        items[0] = MP_OBJ_NEW_SMALL_INT(rx_msg.ExtId);
+    }
+    items[1] = rx_msg.RTR == CAN_RTR_REMOTE ? mp_const_true : mp_const_false;
+    items[2] = MP_OBJ_NEW_SMALL_INT(rx_msg.FMI);
+
+    // Return the result
+    return ret_obj;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_can_recv_obj, 1, pyb_can_recv);
+
+// initfilterbanks(n)
+STATIC mp_obj_t pyb_can_initfilterbanks(mp_obj_t self, mp_obj_t bank_in) {
+    can2_start_bank = mp_obj_get_int(bank_in);
+
+    for (int f = 0; f < 28; f++) {
+        can_clearfilter(f, can2_start_bank);
+    }
+
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_can_initfilterbanks_fun_obj, pyb_can_initfilterbanks);
+STATIC MP_DEFINE_CONST_CLASSMETHOD_OBJ(pyb_can_initfilterbanks_obj, MP_ROM_PTR(&pyb_can_initfilterbanks_fun_obj));
+
+STATIC mp_obj_t pyb_can_clearfilter(mp_obj_t self_in, mp_obj_t bank_in) {
+    pyb_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_int_t f = mp_obj_get_int(bank_in);
+    if (self->can_id == 2) {
+        f += can2_start_bank;
+    }
+    can_clearfilter(f, can2_start_bank);
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_can_clearfilter_obj, pyb_can_clearfilter);
+
+// setfilter(bank, mode, fifo, params, *, rtr)
+#define EXTENDED_ID_TO_16BIT_FILTER(id) (((id & 0xC00000) >> 13) | ((id & 0x38000) >> 15)) | 8
+STATIC mp_obj_t pyb_can_setfilter(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    enum { ARG_bank, ARG_mode, ARG_fifo, ARG_params, ARG_rtr };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_bank,     MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
+        { MP_QSTR_mode,     MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
+        { MP_QSTR_fifo,     MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = CAN_FILTER_FIFO0} },
+        { MP_QSTR_params,   MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
+        { MP_QSTR_rtr,      MP_ARG_KW_ONLY  | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
+    };
+
+    // parse args
+    pyb_can_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    size_t len;
+    size_t rtr_len;
+    mp_uint_t rtr_masks[4] = {0, 0, 0, 0};
+    mp_obj_t *rtr_flags;
+    mp_obj_t *params;
+    mp_obj_get_array(args[ARG_params].u_obj, &len, &params);
+    if (args[ARG_rtr].u_obj != MP_OBJ_NULL){
+        mp_obj_get_array(args[ARG_rtr].u_obj, &rtr_len, &rtr_flags);
+    }
+
+    CAN_FilterConfTypeDef filter;
+    if (args[ARG_mode].u_int == MASK16 || args[ARG_mode].u_int == LIST16) {
+        if (len != 4) {
+            goto error;
+        }
+        filter.FilterScale = CAN_FILTERSCALE_16BIT;
+        if (self->extframe) {
+            if (args[ARG_rtr].u_obj != MP_OBJ_NULL) {
+                if (args[ARG_mode].u_int == MASK16) {
+                    rtr_masks[0] = mp_obj_get_int(rtr_flags[0]) ? 0x02 : 0;
+                    rtr_masks[1] = 0x02;
+                    rtr_masks[2] = mp_obj_get_int(rtr_flags[1]) ? 0x02 : 0;
+                    rtr_masks[3] = 0x02;
+                } else {  // LIST16
+                    rtr_masks[0] = mp_obj_get_int(rtr_flags[0]) ? 0x02 : 0;
+                    rtr_masks[1] = mp_obj_get_int(rtr_flags[1]) ? 0x02 : 0;
+                    rtr_masks[2] = mp_obj_get_int(rtr_flags[2]) ? 0x02 : 0;
+                    rtr_masks[3] = mp_obj_get_int(rtr_flags[3]) ? 0x02 : 0;
+                }
+            }
+            filter.FilterIdLow      = EXTENDED_ID_TO_16BIT_FILTER(mp_obj_get_int(params[0])) | rtr_masks[0]; // id1
+            filter.FilterMaskIdLow  = EXTENDED_ID_TO_16BIT_FILTER(mp_obj_get_int(params[1])) | rtr_masks[1]; // mask1
+            filter.FilterIdHigh     = EXTENDED_ID_TO_16BIT_FILTER(mp_obj_get_int(params[2])) | rtr_masks[2]; // id2
+            filter.FilterMaskIdHigh = EXTENDED_ID_TO_16BIT_FILTER(mp_obj_get_int(params[3])) | rtr_masks[3]; // mask2
+        } else { // Basic frames
+            if (args[ARG_rtr].u_obj != MP_OBJ_NULL) {
+                if (args[ARG_mode].u_int == MASK16) {
+                    rtr_masks[0] = mp_obj_get_int(rtr_flags[0]) ? 0x10 : 0;
+                    rtr_masks[1] = 0x10;
+                    rtr_masks[2] = mp_obj_get_int(rtr_flags[1]) ? 0x10 : 0;
+                    rtr_masks[3] = 0x10;
+                } else {  // LIST16
+                    rtr_masks[0] = mp_obj_get_int(rtr_flags[0]) ? 0x10 : 0;
+                    rtr_masks[1] = mp_obj_get_int(rtr_flags[1]) ? 0x10 : 0;
+                    rtr_masks[2] = mp_obj_get_int(rtr_flags[2]) ? 0x10 : 0;
+                    rtr_masks[3] = mp_obj_get_int(rtr_flags[3]) ? 0x10 : 0;
+                }
+            }
+            filter.FilterIdLow      = (mp_obj_get_int(params[0]) << 5) | rtr_masks[0]; // id1
+            filter.FilterMaskIdLow  = (mp_obj_get_int(params[1]) << 5) | rtr_masks[1]; // mask1
+            filter.FilterIdHigh     = (mp_obj_get_int(params[2]) << 5) | rtr_masks[2]; // id2
+            filter.FilterMaskIdHigh = (mp_obj_get_int(params[3]) << 5) | rtr_masks[3]; // mask2
+        }
+        if (args[ARG_mode].u_int == MASK16) {
+            filter.FilterMode  = CAN_FILTERMODE_IDMASK;
+        }
+        if (args[ARG_mode].u_int == LIST16) {
+            filter.FilterMode  = CAN_FILTERMODE_IDLIST;
+        }
+    }
+    else if (args[ARG_mode].u_int == MASK32 || args[ARG_mode].u_int == LIST32) {
+        if (len != 2) {
+            goto error;
+        }
+        filter.FilterScale = CAN_FILTERSCALE_32BIT;
+        if (args[ARG_rtr].u_obj != MP_OBJ_NULL) {
+            if (args[ARG_mode].u_int == MASK32) {
+                rtr_masks[0] = mp_obj_get_int(rtr_flags[0]) ? 0x02 : 0;
+                rtr_masks[1] = 0x02;
+            } else {  // LIST32
+                rtr_masks[0] = mp_obj_get_int(rtr_flags[0]) ? 0x02 : 0;
+                rtr_masks[1] = mp_obj_get_int(rtr_flags[1]) ? 0x02 : 0;
+            }
+        }
+        filter.FilterIdHigh     = (mp_obj_get_int(params[0]) & 0x1FFFE000)  >> 13;
+        filter.FilterIdLow      = (((mp_obj_get_int(params[0]) & 0x00001FFF) << 3) | 4) | rtr_masks[0];
+        filter.FilterMaskIdHigh = (mp_obj_get_int(params[1]) & 0x1FFFE000 ) >> 13;
+        filter.FilterMaskIdLow  = (((mp_obj_get_int(params[1]) & 0x00001FFF) << 3) | 4) | rtr_masks[1];
+        if (args[ARG_mode].u_int == MASK32) {
+            filter.FilterMode  = CAN_FILTERMODE_IDMASK;
+        }
+        if (args[ARG_mode].u_int == LIST32) {
+            filter.FilterMode  = CAN_FILTERMODE_IDLIST;
+        }
+    } else {
+        goto error;
+    }
+
+    filter.FilterFIFOAssignment = args[ARG_fifo].u_int;
+    filter.FilterNumber = args[ARG_bank].u_int;
+    if (self->can_id == 1) {
+        if (filter.FilterNumber >= can2_start_bank) {
+            goto error;
+        }
+    } else if (self->can_id == 2) {
+        filter.FilterNumber = filter.FilterNumber + can2_start_bank;
+        if (filter.FilterNumber > 27) {
+            goto error;
+        }
+    } else {
+        if (filter.FilterNumber > 13) { // CAN3 is independant and has its own 14 filters.
+            goto error;
+        }
+    }
+    filter.FilterActivation = ENABLE;
+    filter.BankNumber = can2_start_bank;
+    HAL_CAN_ConfigFilter(&self->can, &filter);
+
+    return mp_const_none;
+
+error:
+    mp_raise_ValueError("CAN filter parameter error");
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_can_setfilter_obj, 1, pyb_can_setfilter);
+
+STATIC mp_obj_t pyb_can_rxcallback(mp_obj_t self_in, mp_obj_t fifo_in, mp_obj_t callback_in) {
+    pyb_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_int_t fifo = mp_obj_get_int(fifo_in);
+    mp_obj_t *callback;
+
+    callback = (fifo == 0) ? &self->rxcallback0 : &self->rxcallback1;
+    if (callback_in == mp_const_none) {
+        __HAL_CAN_DISABLE_IT(&self->can, (fifo == 0) ? CAN_IT_FMP0 : CAN_IT_FMP1);
+        __HAL_CAN_DISABLE_IT(&self->can, (fifo == 0) ? CAN_IT_FF0 : CAN_IT_FF1);
+        __HAL_CAN_DISABLE_IT(&self->can, (fifo == 0) ? CAN_IT_FOV0 : CAN_IT_FOV1);
+        __HAL_CAN_CLEAR_FLAG(&self->can, (fifo == CAN_FIFO0) ? CAN_FLAG_FF0 : CAN_FLAG_FF1);
+        __HAL_CAN_CLEAR_FLAG(&self->can, (fifo == CAN_FIFO0) ? CAN_FLAG_FOV0 : CAN_FLAG_FOV1);
+        *callback = mp_const_none;
+    } else if (*callback != mp_const_none) {
+        // Rx call backs has already been initialized
+        // only the callback function should be changed
+        *callback = callback_in;
+    } else if (mp_obj_is_callable(callback_in)) {
+        *callback = callback_in;
+        uint32_t irq = 0;
+        if (self->can_id == PYB_CAN_1) {
+            irq = (fifo == 0) ? CAN1_RX0_IRQn : CAN1_RX1_IRQn;
+        #if defined(CAN2)
+        } else if (self->can_id == PYB_CAN_2) {
+            irq = (fifo == 0) ? CAN2_RX0_IRQn : CAN2_RX1_IRQn;
+        #endif
+        #if defined(CAN3)
+        } else {
+            irq = (fifo == 0) ? CAN3_RX0_IRQn : CAN3_RX1_IRQn;
+        #endif
+        }
+        NVIC_SetPriority(irq, IRQ_PRI_CAN);
+        HAL_NVIC_EnableIRQ(irq);
+        __HAL_CAN_ENABLE_IT(&self->can, (fifo == 0) ? CAN_IT_FMP0 : CAN_IT_FMP1);
+        __HAL_CAN_ENABLE_IT(&self->can, (fifo == 0) ? CAN_IT_FF0  : CAN_IT_FF1);
+        __HAL_CAN_ENABLE_IT(&self->can, (fifo == 0) ? CAN_IT_FOV0 : CAN_IT_FOV1);
+    }
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_3(pyb_can_rxcallback_obj, pyb_can_rxcallback);
+
+STATIC const mp_rom_map_elem_t pyb_can_locals_dict_table[] = {
+    // instance methods
+    { MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&pyb_can_init_obj) },
+    { MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&pyb_can_deinit_obj) },
+    { MP_ROM_QSTR(MP_QSTR_restart), MP_ROM_PTR(&pyb_can_restart_obj) },
+    { MP_ROM_QSTR(MP_QSTR_state), MP_ROM_PTR(&pyb_can_state_obj) },
+    { MP_ROM_QSTR(MP_QSTR_info), MP_ROM_PTR(&pyb_can_info_obj) },
+    { MP_ROM_QSTR(MP_QSTR_any), MP_ROM_PTR(&pyb_can_any_obj) },
+    { MP_ROM_QSTR(MP_QSTR_send), MP_ROM_PTR(&pyb_can_send_obj) },
+    { MP_ROM_QSTR(MP_QSTR_recv), MP_ROM_PTR(&pyb_can_recv_obj) },
+    { MP_ROM_QSTR(MP_QSTR_initfilterbanks), MP_ROM_PTR(&pyb_can_initfilterbanks_obj) },
+    { MP_ROM_QSTR(MP_QSTR_setfilter), MP_ROM_PTR(&pyb_can_setfilter_obj) },
+    { MP_ROM_QSTR(MP_QSTR_clearfilter), MP_ROM_PTR(&pyb_can_clearfilter_obj) },
+    { MP_ROM_QSTR(MP_QSTR_rxcallback), MP_ROM_PTR(&pyb_can_rxcallback_obj) },
+
+    // class constants
+    // Note: we use the ST constants >> 4 so they fit in a small-int.  The
+    // right-shift is undone when the constants are used in the init function.
+    { MP_ROM_QSTR(MP_QSTR_NORMAL), MP_ROM_INT(CAN_MODE_NORMAL >> 4) },
+    { MP_ROM_QSTR(MP_QSTR_LOOPBACK), MP_ROM_INT(CAN_MODE_LOOPBACK >> 4) },
+    { MP_ROM_QSTR(MP_QSTR_SILENT), MP_ROM_INT(CAN_MODE_SILENT >> 4) },
+    { MP_ROM_QSTR(MP_QSTR_SILENT_LOOPBACK), MP_ROM_INT(CAN_MODE_SILENT_LOOPBACK >> 4) },
+    { MP_ROM_QSTR(MP_QSTR_MASK16), MP_ROM_INT(MASK16) },
+    { MP_ROM_QSTR(MP_QSTR_LIST16), MP_ROM_INT(LIST16) },
+    { MP_ROM_QSTR(MP_QSTR_MASK32), MP_ROM_INT(MASK32) },
+    { MP_ROM_QSTR(MP_QSTR_LIST32), MP_ROM_INT(LIST32) },
+
+    // values for CAN.state()
+    { MP_ROM_QSTR(MP_QSTR_STOPPED), MP_ROM_INT(CAN_STATE_STOPPED) },
+    { MP_ROM_QSTR(MP_QSTR_ERROR_ACTIVE), MP_ROM_INT(CAN_STATE_ERROR_ACTIVE) },
+    { MP_ROM_QSTR(MP_QSTR_ERROR_WARNING), MP_ROM_INT(CAN_STATE_ERROR_WARNING) },
+    { MP_ROM_QSTR(MP_QSTR_ERROR_PASSIVE), MP_ROM_INT(CAN_STATE_ERROR_PASSIVE) },
+    { MP_ROM_QSTR(MP_QSTR_BUS_OFF), MP_ROM_INT(CAN_STATE_BUS_OFF) },
+};
+STATIC MP_DEFINE_CONST_DICT(pyb_can_locals_dict, pyb_can_locals_dict_table);
+
+STATIC mp_uint_t can_ioctl(mp_obj_t self_in, mp_uint_t request, uintptr_t arg, int *errcode) {
+    pyb_can_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_uint_t ret;
+    if (request == MP_STREAM_POLL) {
+        uintptr_t flags = arg;
+        ret = 0;
+        if ((flags & MP_STREAM_POLL_RD)
+            && ((__HAL_CAN_MSG_PENDING(&self->can, CAN_FIFO0) != 0)
+                || (__HAL_CAN_MSG_PENDING(&self->can, CAN_FIFO1) != 0))) {
+            ret |= MP_STREAM_POLL_RD;
+        }
+        if ((flags & MP_STREAM_POLL_WR) && (self->can.Instance->TSR & CAN_TSR_TME)) {
+            ret |= MP_STREAM_POLL_WR;
+        }
+    } else {
+        *errcode = MP_EINVAL;
+        ret = -1;
+    }
+    return ret;
+}
+
+void pyb_can_handle_callback(pyb_can_obj_t *self, uint fifo_id, mp_obj_t callback, mp_obj_t irq_reason) {
+    if (callback != mp_const_none) {
+        mp_sched_lock();
+        gc_lock();
+        nlr_buf_t nlr;
+        if (nlr_push(&nlr) == 0) {
+            mp_call_function_2(callback, MP_OBJ_FROM_PTR(self), irq_reason);
+            nlr_pop();
+        } else {
+            // Uncaught exception; disable the callback so it doesn't run again.
+            pyb_can_rxcallback(MP_OBJ_FROM_PTR(self), MP_OBJ_NEW_SMALL_INT(fifo_id), mp_const_none);
+            printf("uncaught exception in CAN(%u) rx interrupt handler\n", self->can_id);
+            mp_obj_print_exception(&mp_plat_print, MP_OBJ_FROM_PTR(nlr.ret_val));
+        }
+        gc_unlock();
+        mp_sched_unlock();
+    }
+}
+
+STATIC const mp_stream_p_t can_stream_p = {
+    //.read = can_read, // is read sensible for CAN?
+    //.write = can_write, // is write sensible for CAN?
+    .ioctl = can_ioctl,
+    .is_text = false,
+};
+
+const mp_obj_type_t pyb_can_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_CAN,
+    .print = pyb_can_print,
+    .make_new = pyb_can_make_new,
+    .protocol = &can_stream_p,
+    .locals_dict = (mp_obj_dict_t*)&pyb_can_locals_dict,
+};
+
+#endif // MICROPY_HW_ENABLE_CAN
diff --git a/ports/stm32/stm32_it.c b/ports/stm32/stm32_it.c
index 9f5a886f3..3a4709d9f 100644
--- a/ports/stm32/stm32_it.c
+++ b/ports/stm32/stm32_it.c
@@ -79,7 +79,6 @@
 #include "timer.h"
 #include "uart.h"
 #include "storage.h"
-#include "can.h"
 #include "dma.h"
 #include "i2c.h"
 #include "usb.h"
@@ -792,66 +791,6 @@ void UART10_IRQHandler(void) {
 
 #endif
 
-#if defined(MICROPY_HW_CAN1_TX)
-void CAN1_RX0_IRQHandler(void) {
-    IRQ_ENTER(CAN1_RX0_IRQn);
-    can_rx_irq_handler(PYB_CAN_1, CAN_FIFO0);
-    IRQ_EXIT(CAN1_RX0_IRQn);
-}
-
-void CAN1_RX1_IRQHandler(void) {
-    IRQ_ENTER(CAN1_RX1_IRQn);
-    can_rx_irq_handler(PYB_CAN_1, CAN_FIFO1);
-    IRQ_EXIT(CAN1_RX1_IRQn);
-}
-
-void CAN1_SCE_IRQHandler(void) {
-    IRQ_ENTER(CAN1_SCE_IRQn);
-    can_sce_irq_handler(PYB_CAN_1);
-    IRQ_EXIT(CAN1_SCE_IRQn);
-}
-#endif
-
-#if defined(MICROPY_HW_CAN2_TX)
-void CAN2_RX0_IRQHandler(void) {
-    IRQ_ENTER(CAN2_RX0_IRQn);
-    can_rx_irq_handler(PYB_CAN_2, CAN_FIFO0);
-    IRQ_EXIT(CAN2_RX0_IRQn);
-}
-
-void CAN2_RX1_IRQHandler(void) {
-    IRQ_ENTER(CAN2_RX1_IRQn);
-    can_rx_irq_handler(PYB_CAN_2, CAN_FIFO1);
-    IRQ_EXIT(CAN2_RX1_IRQn);
-}
-
-void CAN2_SCE_IRQHandler(void) {
-    IRQ_ENTER(CAN2_SCE_IRQn);
-    can_sce_irq_handler(PYB_CAN_2);
-    IRQ_EXIT(CAN2_SCE_IRQn);
-}
-#endif
-
-#if defined(MICROPY_HW_CAN3_TX)
-void CAN3_RX0_IRQHandler(void) {
-    IRQ_ENTER(CAN3_RX0_IRQn);
-    can_rx_irq_handler(PYB_CAN_3, CAN_FIFO0);
-    IRQ_EXIT(CAN3_RX0_IRQn);
-}
-
-void CAN3_RX1_IRQHandler(void) {
-    IRQ_ENTER(CAN3_RX1_IRQn);
-    can_rx_irq_handler(PYB_CAN_3, CAN_FIFO1);
-    IRQ_EXIT(CAN3_RX1_IRQn);
-}
-
-void CAN3_SCE_IRQHandler(void) {
-    IRQ_ENTER(CAN3_SCE_IRQn);
-    can_sce_irq_handler(PYB_CAN_3);
-    IRQ_EXIT(CAN3_SCE_IRQn);
-}
-#endif
-
 #if MICROPY_PY_PYB_LEGACY
 
 #if defined(MICROPY_HW_I2C1_SCL)