diff options
| -rw-r--r-- | ports/stm32/pyb_can.c | 31 |
1 files changed, 24 insertions, 7 deletions
diff --git a/ports/stm32/pyb_can.c b/ports/stm32/pyb_can.c index bdb0e9034..aa3312932 100644 --- a/ports/stm32/pyb_can.c +++ b/ports/stm32/pyb_can.c @@ -59,6 +59,16 @@ #define CAN_DEFAULT_BS1 (8) #define CAN_DEFAULT_BS2 (3) +#define CAN_MAXIMUM_NBRP (512) +#define CAN_MAXIMUM_NBS1 (256) +#define CAN_MAXIMUM_NBS2 (128) +// Minimum Nominal time segment for FDCAN is 2. +#define CAN_MINIMUM_TSEG (2) + +#define CAN_MAXIMUM_DBRP (32) +#define CAN_MAXIMUM_DBS1 (32) +#define CAN_MAXIMUM_DBS2 (16) + #define CAN_MODE_NORMAL FDCAN_MODE_NORMAL #define CAN_MODE_LOOPBACK FDCAN_MODE_EXTERNAL_LOOPBACK #define CAN_MODE_SILENT FDCAN_MODE_BUS_MONITORING @@ -97,6 +107,11 @@ extern const uint8_t DLCtoBytes[16]; #define CAN_DEFAULT_BS1 (6) #define CAN_DEFAULT_BS2 (8) +#define CAN_MAXIMUM_NBRP (1024) +#define CAN_MAXIMUM_NBS1 (16) +#define CAN_MAXIMUM_NBS2 (8) +#define CAN_MINIMUM_TSEG (1) + #define CAN_IT_FIFO0_FULL CAN_IT_FF0 #define CAN_IT_FIFO1_FULL CAN_IT_FF1 #define CAN_IT_FIFO0_OVRF CAN_IT_FOV0 @@ -178,13 +193,13 @@ STATIC uint32_t pyb_can_get_source_freq() { } STATIC void pyb_can_get_bit_timing(mp_uint_t baudrate, mp_uint_t sample_point, + uint32_t max_brp, uint32_t max_bs1, uint32_t max_bs2, uint32_t min_tseg, mp_int_t *bs1_out, mp_int_t *bs2_out, mp_int_t *prescaler_out) { uint32_t can_kern_clk = pyb_can_get_source_freq(); - - // The following max values work on all MCUs for classical CAN. - for (int brp = 1; brp < 512; brp++) { - for (int bs1 = 1; bs1 < 16; bs1++) { - for (int bs2 = 1; bs2 < 8; bs2++) { + // Calculate CAN bit timing. + for (uint32_t brp = 1; brp < max_brp; brp++) { + for (uint32_t bs1 = min_tseg; bs1 < max_bs1; bs1++) { + for (uint32_t bs2 = min_tseg; bs2 < max_bs2; bs2++) { if ((baudrate == (can_kern_clk / (brp * (1 + bs1 + bs2)))) && ((sample_point * 10) == (((1 + bs1) * 1000) / (1 + bs1 + bs2)))) { *bs1_out = bs1; @@ -229,9 +244,10 @@ STATIC mp_obj_t pyb_can_init_helper(pyb_can_obj_t *self, size_t n_args, const mp // set the CAN configuration values memset(&self->can, 0, sizeof(self->can)); - // Calculate CAN bit timing from baudrate if provided + // Calculate CAN nominal bit timing from baudrate if provided if (args[ARG_baudrate].u_int != 0) { pyb_can_get_bit_timing(args[ARG_baudrate].u_int, args[ARG_sample_point].u_int, + CAN_MAXIMUM_NBRP, CAN_MAXIMUM_NBS1, CAN_MAXIMUM_NBS2, CAN_MINIMUM_TSEG, &args[ARG_bs1].u_int, &args[ARG_bs2].u_int, &args[ARG_prescaler].u_int); } @@ -240,9 +256,10 @@ STATIC mp_obj_t pyb_can_init_helper(pyb_can_obj_t *self, size_t n_args, const mp if (args[ARG_brs_sample_point].u_int == 0) { args[ARG_brs_sample_point].u_int = args[ARG_sample_point].u_int; } - // Calculate BRS CAN bit timing from baudrate if provided + // Calculate CAN data bit timing from baudrate if provided if (args[ARG_brs_baudrate].u_int != 0) { pyb_can_get_bit_timing(args[ARG_brs_baudrate].u_int, args[ARG_brs_sample_point].u_int, + CAN_MAXIMUM_DBRP, CAN_MAXIMUM_DBS1, CAN_MAXIMUM_DBS2, 1, &args[ARG_brs_bs1].u_int, &args[ARG_brs_bs2].u_int, &args[ARG_brs_prescaler].u_int); } // Set BRS bit timings. |