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authorrobert-hh <robert@hammelrath.com>2021-06-18 17:12:44 +0200
committerDamien George <damien@micropython.org>2022-04-04 14:11:31 +1000
commit7a447e08b23f47fac6ebcbe5d60c4e1d0fe0d157 (patch)
treedaa938c7d64250c8fb7e10ea6b19e2bef480b300 /docs/mimxrt/quickref.rst
parent71344c15f4ef6efc62fbaeef830fa357ee30dce0 (diff)
docs: Add quickref and docs for mimxrt, including network.LAN docs.
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+.. _mimxrt_quickref:
+
+Quick reference for the i.MXRT family
+=====================================
+
+.. image:: img/teensy_4.1.jpg
+ :alt: Teensy 4.1 board
+ :width: 640px
+
+The Teensy 4.1 board.
+
+Below is a quick reference for i.MXRT-based boards. If it is your first time
+working with this board it may be useful to get an overview of the microcontroller:
+
+.. toctree::
+ :maxdepth: 1
+
+ general.rst
+ tutorial/intro.rst
+
+
+Installing MicroPython
+----------------------
+
+See the corresponding section of tutorial: :ref:`mimxrt_intro`. It also includes
+a troubleshooting subsection.
+
+General board control
+---------------------
+
+The MicroPython REPL is on the USB port, configured in VCP mode.
+Tab-completion is useful to find out what methods an object has.
+Paste mode (ctrl-E) is useful to paste a large slab of Python code into
+the REPL.
+
+The :mod:`machine` module::
+
+ import machine
+
+ machine.freq() # get the current frequency of the CPU
+
+Delay and timing
+----------------
+
+Use the :mod:`time <time>` module::
+
+ import time
+
+ time.sleep(1) # sleep for 1 second
+ time.sleep_ms(500) # sleep for 500 milliseconds
+ time.sleep_us(10) # sleep for 10 microseconds
+ start = time.ticks_ms() # get millisecond counter
+ delta = time.ticks_diff(time.ticks_ms(), start) # compute time difference
+
+Timers
+------
+
+The i.MXRT port has three hardware timers. Use the :ref:`machine.Timer <machine.Timer>` class
+with a timer ID from 0 to 2 (inclusive)::
+
+ from machine import Timer
+
+ tim0 = Timer(0)
+ tim0.init(period=5000, mode=Timer.ONE_SHOT, callback=lambda t:print(0))
+
+ tim1 = Timer(1)
+ tim1.init(period=2000, mode=Timer.PERIODIC, callback=lambda t:print(1))
+
+The period is in milliseconds.
+
+Virtual timers are not currently supported on this port.
+
+.. _mimxrt_Pins_and_GPIO:
+
+Pins and GPIO
+-------------
+
+Use the :ref:`machine.Pin <machine.Pin>` class::
+
+ from machine import Pin
+
+ p0 = Pin('D0', Pin.OUT) # create output pin on GPIO0
+ p0.on() # set pin to "on" (high) level
+ p0.off() # set pin to "off" (low) level
+ p0.value(1) # set pin to on/high
+
+ p2 = Pin('D2', Pin.IN) # create input pin on GPIO2
+ print(p2.value()) # get value, 0 or 1
+
+ p4 = Pin('D4', Pin.IN, Pin.PULL_UP) # enable internal pull-up resistor
+ p5 = Pin('D5', Pin.OUT, value=1) # set pin high on creation
+
+ p6 = Pin(pin.cpu.GPIO_B1_15, Pin.OUT) # Use the cpu pin name.
+
+Available Pins follow the ranges and labelling of the respective board, like:
+
+- 0-33 for Teensy 4.0,
+- 0-21 for the MIMXRT10xx-EVK board, or 'D0-Dxx', or 'A0-Ann',
+- 0-14 for the Olimex RT1010Py board, or 'D0'-'Dxx' and 'A0'-'Ann'
+- 'J3_xx', 'J4_xx', 'J5_xx' for the Seeed ARCH MIX board,
+
+or the pin names of the Pin.board or Pin.cpu classes.
+
+Notes:
+
+* The MIMXRT1xxx-EVK boards may have other on-board devices connected to these
+ pins, limiting it's use for input or output.
+* At the MIMXRT1010_EVK, pins D4, D5 and D9 of the Arduino connector are by
+ default not connected to the MCU. For details refer to the schematics.
+* At the MIMXRT1170_EVK board, the inner rows of the Arduino connectors are assigned as follows:
+ - D16 - D23: J9, odd pin numbers; D17 is by default not connected.
+ - D24 - D27: J26, odd pin numbers; J63-J66 have to be closed to enable these pins.
+ - D29 - D36: J25, odd pin numbers; D29 and D30 are by default not connected.
+
+There's a higher-level abstraction :ref:`machine.Signal <machine.Signal>`
+which can be used to invert a pin. Useful for illuminating active-low LEDs
+using ``on()`` or ``value(1)``.
+
+UART (serial bus)
+-----------------
+
+See :ref:`machine.UART <machine.UART>`. ::
+
+ from machine import UART
+
+ uart1 = UART(1, baudrate=115200)
+ uart1.write('hello') # write 5 bytes
+ uart1.read(5) # read up to 5 bytes
+
+The i.MXRT has up to eight hardware UARTs, but not every board exposes all
+TX and RX pins for users. The pin assignment of UARTs to pins is fixed.
+The UARTs are numbered 1..8. The rx/tx pins are assigned according to the
+tables below:
+
+================ =========== =========== =========== ===========
+Board / Pin UART0 UART1 UART2 UART3
+================ =========== =========== =========== ===========
+Teensy 4.0 - 0/1 7/8 14/15
+Teensy 4.1 - 0/1 7/8 14/15
+MIMXRT1010-EVK Debug USB D0/D1 D7/D6 -
+MIMXRT1015-EVK Debug USB D0/D1 D7/A1 -
+MIMXRT1020-EVK Debug USB D0/D1 D9/D6 D10/D13
+MIMXRT1050-EVK Debug USB D0/D1 D7/D6 D8/D9
+MIMXRT1050-EVKB Debug USB D0/D1 D7/D6 D8/D9
+MIMXRT1060-EVK Debug USB D0/D1 D7/D6 D8/D9
+MIMXRT1064-EVK Debug USB D0/D1 D7/D6 D8/D9
+MIMXRT1170-EVK Debug USB D0/D1 D12/D11 D10/D13
+Olimex RT1010Py - RxD/TxD D5/D6 -
+Seeed ARCH MIX - J3_19/J3_20 J4_16/J4_17 J4_06/J4_07
+================ =========== =========== =========== ===========
+
+================ =========== =========== ======= ======= =====
+Board / Pin UART4 UART5 UART6 UART7 UART8
+================ =========== =========== ======= ======= =====
+Teensy 4.0 16/17 21/20 25/24 28/29 -
+Teensy 4.1 16/17 21/20 25/24 28/29 34/35
+MIMXRT1010-EVK - - - - -
+MIMXRT1015-EVK - - - - -
+MIMXRT1020-EVK D15/D14 A1/A0 - - -
+MIMXRT1050-EVK A1/A0 - - - -
+MIMXRT1050-EVKB A1/A0 - - - -
+MIMXRT1060-EVK A1/A0 - - - -
+MIMXRT1064-EVK A1/A0 - - - -
+MIMXRT1170-EVK D15/D14 D25/D26 D33/D34 D35/D36 -
+Olimex RT1010Py - - - - -
+Seeed ARCH MIX J4_10/J4_11 J5_08/J5_12 - - -
+================ =========== =========== ======= ======= =====
+
+PWM (pulse width modulation)
+----------------------------
+
+The i.MXRT has up to four dedicated PWM modules with four FLEXPWM submodules each
+and up to four QTMR modules with four channels, which can be used to generate
+a PWM signal or signal pair.
+
+The PWM functions are provided by the :ref:`machine.PWM <machine.PWM>` class.
+It supports all basic methods listed for that class and a few additional methods for
+handling signal groups. ::
+
+ # Samples for Teensy
+ #
+
+ from machine import Pin, PWM
+
+ pwm2 = PWM(Pin(2)) # create PWM object from a pin
+ pwm2.freq() # get current frequency
+ pwm2.freq(1000) # set frequency
+ pwm2.duty_u16() # get current duty cycle, range 0-65535
+ pwm2.duty_u16(200) # set duty cycle, range 0-65535
+ pwm2.deinit() # turn off PWM on the pin
+ # create a complementary signal pair on Pin 2 and 3
+ pwm2 = PWM((2, 3), freq=2000, duty_ns=20000)
+
+ # Create a group of four synchronized signals.
+ # Start with Pin(4) at submodule 0, which creates the sync pulse.
+ pwm4 = PWM(Pin(4), freq=1000, align=PWM.HEAD)
+ # Pins 5, 6, and 9 are pins at the same module
+ pwm5 = PWM(Pin(5), freq=1000, duty_u16=10000, align=PWM.HEAD, sync=True)
+ pwm6 = PWM(Pin(6), freq=1000, duty_u16=20000, align=PWM.HEAD, sync=True)
+ pwm9 = PWM(Pin(9), freq=1000, duty_u16=30000, align=PWM.HEAD, sync=True)
+
+ pwm3 # show the PWM objects properties
+
+
+PWM Constructor
+```````````````
+
+.. class:: PWM(dest, freq, duty_u16, duty_ns, *, center, align, invert, sync, xor, deadtime)
+ :noindex:
+
+ Construct and return a new PWM object using the following parameters:
+
+ - *dest* is the entity on which the PWM is output, which is usually a
+ :ref:`machine.Pin <machine.Pin>` object, but a port may allow other values,
+ like integers or strings, which designate a Pin in the machine.PIN class.
+ *dest* is either a single object or a two element object tuple.
+ If the object tuple is specified, the two pins act in complementary
+ mode. These two pins must be the A/B channels of the same submodule.
+
+ PWM objects are either provided by a FLEXPWM module or a QTMR module.
+ The i.MXRT devices have either two or four FLEXPWM and QTMR modules.
+ Each FLEXPWM module has four submodules with three channels, each,
+ called A, B and X. Each QTMR module has four channels.
+ Each FLEXPWM submodule or QTMR channel may be set to different parameters.
+ Not every channel is routed to a board pin. Details are listed below.
+
+ Setting *freq* affects the three channels of the same FLEXPWM submodule.
+ Only one of *duty_u16* and *duty_ns* should be specified at a time.
+
+ Keyword arguments:
+
+ - *freq* should be an integer which sets the frequency in Hz for the
+ PWM cycle. The valid frequency range is 15 Hz resp. 18Hz resp. 24Hz up to > 1 MHz.
+ - *duty_u16* sets the duty cycle as a ratio ``duty_u16 / 65536``.
+ The duty cycle of a X channel can only be changed, if the A and B channel
+ of the respective submodule is not used. Otherwise the duty_16 value of the
+ X channel is 32768 (50%).
+ - *duty_ns* sets the pulse width in nanoseconds. The limitation for X channels
+ apply as well.
+ - *center*\=value. An integer sets the center of the pulse within the pulse period.
+ The range is 0-65535. The resulting pulse will last from center - duty_u16/2 to
+ center + duty_u16/2.
+ - *align*\=value. Shortcuts for the pulse center setting, causing the pulse either at
+ the center of the frame (value=0), the leading edge at the begin (value=1) or the
+ trailing edge at the end of a pulse period (value=2).
+ - *invert*\=True|False channel_mask. Setting a bit in the mask inverts the respective channel.
+ Bit 0 inverts the first specified channel, bit 2 the second. The default is 0.
+ - *sync*\=True|False. If a channel of a module's submodule 0 is already active, other
+ submodules of the same module can be forced to be synchronous to submodule 0. Their
+ pulse period start then at at same clock cycle. The default is False.
+ - *xor*\=0|1|2. If set to 1 or 2, the channel will output the XOR'd signal from channels
+ A or B. If set to 1 on channel A or B, both A and B will show the same signal. If set
+ to 2, A and B will show alternating signals. For details and an illustration, please
+ refer to the MCU's reference manual, chapter "Double Switching PWMs".
+ - *deadtime*\=time_ns. This setting affects complementary channels and defines a deadtime
+ between an edge of a first channel and the edge of the next channel, in which both
+ channels are set to low. That allows connected H-bridges to switch off one side
+ of a push-pull driver before switching on the other side.
+
+PWM Methods
+```````````
+
+The methods are identical to the generic :ref:`machine.PWM <machine.PWM>` class,
+with additional keyword arguments to the init() method, matchings those of the constructor.
+
+Each FLEX submodule or QTMR module may run at different frequencies. The PWM signal
+is created by dividing the pwm_clk signal by an integral factor, according to the formula::
+
+ f = pwm_clk / (2**n * m)
+
+with n being in the range of 0..7, and m in the range of 2..65536. pmw_clk is 125Mhz
+for MIMXRT1010/1015/1020, 150 MHz for MIMXRT1050/1060/1064 and 160MHz for MIMXRT1170.
+The lowest frequency is pwm_clk/2**23 (15, 18, 20Hz). The highest frequency with
+U16 resolution is pwm_clk/2**16 (1907, 2288, 2441 Hz), the highest frequency
+with 1 percent resolution is pwm_clk/100 (1.25, 1.5, 1.6 MHz). The highest achievable
+frequency is pwm_clk/3 for the A/B channels, and pwm_clk/2 for the X channels and QTMR
+signal.
+
+PWM Pin Assignment
+``````````````````
+
+Pins are specified in the same way as for the Pin class. The following tables show
+the assignment of the board Pins to PWM modules:
+
+=========== ========== ========== ====== ============== ======
+Pin/ MIMXRT 1010 1015 1020 1050/1060/1064 1170
+=========== ========== ========== ====== ============== ======
+D0 - Q1/1 F1/1/B - -
+D1 - Q1/0 F1/1/A - -
+D2 F1/3/B F1/3/A - F1/3/B -
+D3 F1/3/A F1/0/A F2/3/B F4/0/A F1/2/A
+D4 F1/3/A (*) Q1/2 Q2/1 F2/3/A Q4/2
+D5 F1/0/B (*) F1/0/B F2/3/A F1/3/A F1/2/B
+D6 - F1/2/B F2/0/A Q3/2 F1/0/A
+D7 - - F1/0/A Q3/3 -
+D8 F1/0/A F1/1/B F1/0/B F1/1/X Q4/3
+D9 F1/1/B (*) F1/2/A F2/0/B F1/0/X F1/0/B
+D10 F1/3/B - F2/2/B F1/0/B (*) F2/2/B
+D11 F1/2/A - F2/1/A F1/1/A (*) -
+D12 F1/2/B - F2/1/B F1/1/B (*) -
+D13 F1/3/A - F2/2/A F1/0/A (*) F2/2/A
+D14 F1/0/B - - F2/3/B -
+D15 F1/0/A - - F2/3/A -
+A0 - - F1/2/A - -
+A1 F1/3/X F1/3/B F1/2/B - -
+A2 F1/2/X F1/3/A F1/3/A - -
+A3 - F1/2/A F1/3/B - -
+A4 - - - Q3/1 -
+A5 - - - Q3/0 -
+D31 - - - - F1/2/B
+D32 - - - - F1/2/A
+D33 - - - - F1/1/B
+D34 - - - - F1/1/A
+D35 - - - - F1/0/B
+D36 - - - - F1/0/A
+=========== ========== ========== ====== ============== ======
+
+Pins denoted with (*) are by default not wired at the board.
+
+==== ========== ==== ==========
+Pin Teensy 4.0 Pin Teensy 4.1
+==== ========== ==== ==========
+0 F1/1/X 0 F1/1/X
+1 F1/0/X 1 F1/0/X
+2 F4/2/A 2 F4/2/A
+3 F4/2/B 3 F4/2/B
+4 F2/0/A 4 F2/0/A
+5 F2/1/A 5 F2/1/A
+6 F2/2/A 6 F2/2/A
+7 F1/3/B 7 F1/3/B
+8 F1/3/A 8 F1/3/A
+9 F2/2/B 9 F2/2/B
+10 Q1/0 10 Q1/0
+11 Q1/2 11 Q1/2
+12 Q1/1 12 Q1/1
+13 Q2/0 13 Q2/0
+14 Q3/2 14 Q3/2
+15 Q3/3 15 Q3/3
+18 Q3/1 18 Q3/1
+19 Q3/0 19 Q3/0
+22 F4/0/A 22 F4/0/A
+23 F4/1/A 23 F4/1/A
+24 F1/2/X 24 F1/2/X
+25 F1/3/X 25 F1/3/X
+28 F3/1/B 28 F3/1/B
+29 F3/1/A 29 F3/1/A
+33 F2/0/B 33 F2/0/B
+- - 36 F2/3/A
+- - 37 F2/3/B
+DAT1 F1/1/B 42 F1/1/B
+DAT0 F1/1/A 43 F1/1/A
+CLK F1/0/B 44 F1/0/B
+CMD F1/0/A 45 F1/0/A
+DAT2 F1/2/A 46 F1/2/A
+DAT3 F1/2/B 47 F1/2/B
+- - 48 F1/0/B
+- - 49 F1/2/A
+- - 50 F1/2/B
+- - 51 F3/3/B
+- - 52 F1/1/B
+- - 53 F1/1/A
+- - 54 F3/0/A
+==== ========== ==== ==========
+
+========= ==============
+Pin Seeed ARCH MIX
+========= ==============
+J3_04 Q4/3
+J3_10 Q1/3
+J3_12 Q2/3
+J3_13 Q3/3
+J3_16 Q3/0
+J3_17 Q3/1
+J3_19 F1/3/X
+J3_20 F1/2/X
+J4_08 F4/0/A
+J4_09 F4/1/A
+J4_16 Q3/2
+J4_17 Q3/3
+J5_32 Q1/0
+J5_28 Q1/1
+J5_29 Q1/2
+J5_30 Q2/0
+J5_04 Q2/1
+J5_05 Q2/3
+J5_06 F2/0/A
+J5_07 F2/0/B
+J5_08 F2/1/A
+J5_12 F2/1/B
+J5_13 F2/2/A
+J5_14 F2/2/B
+J5_23 F1/3/A
+J5_24 F1/3/B
+J5_25 F2/3/A
+J5_26 F2/3/B
+J5_42 Q3/0
+J5_43 Q3/1
+J5_50 F1/0/X
+LED_RED F2/3/A
+LED_GREEN F1/3/A
+LED_BLUE F1/3/B
+========= ==============
+
+========= ===============
+Pin Olimex RT1010PY
+========= ===============
+D0 -
+D1 F1/0/B
+D2 F1/0/A
+D3 F1/1/B
+D4 F1/1/A
+D5 F1/2/B
+D6 F1/2/A
+D7 F1/3/B
+D8 F1/3/A
+D9 -
+D10 F1/0/B
+D11 F1/0/A
+D12 F1/1/B
+D13 F1/1/A
+D14 -
+A0 -
+A1 F1/2/B
+A2 F1/2/A
+A3 F1/3/B
+A4 F1/3/A
+SDI F1/3/X
+SDO F1/2/X
+CS0 F1/1/X
+SCK F1/0/X
+========= ===============
+
+Legend:
+
+* Qm/n: QTMR module m, channel n
+* Fm/n/l: FLEXPWM module m, submodule n, channel l. The pulse at a X channel
+ is always aligned to the period start.
+
+Pins without a PWM signal are not listed. A signal may be available at more
+than one Pin. FlexPWM pins may also be pure CPU pin, not assigned to a board
+signal. In that case the PWM output is disabled. The PWM channel of a submodule
+0 may still be used as synchronization source for other channels of the same
+module, unless used by another peripheral.
+
+Submodule 0 pins for i.MX RT1011:
+
+================== =======
+Pin Channel
+================== =======
+Pin.cpu.GPIO_01 B
+Pin.cpu.GPIO_02 A
+Pin.cpu.GPIO_AD_12 X
+Pin.cpu.GPIO_SD_01 B
+Pin.cpu.GPIO_SD_02 A
+================== =======
+
+Submodule 0 pins for i.MX RT1021:
+
+===================== ==================
+Pin Module & Channel
+===================== ==================
+Pin.cpu.GPIO_AD_B1_06 FLEXPWM1 Channel A
+Pin.cpu.GPIO_AD_B1_07 FLEXPWM1 Channel B
+Pin.cpu.GPIO_EMC_26 FLEXPWM1 Channel A
+Pin.cpu.GPIO_EMC_27 FLEXPWM1 Channel B
+Pin.cpu.GPIO_AD_B0_14 FLEXPWM2 Channel A
+Pin.cpu.GPIO_AD_B0_15 FLEXPWM2 Channel B
+Pin.cpu.GPIO_EMC_10 FLEXPWM2 Channel X
+Pin.cpu.GPIO_EMC_38 FLEXPWM2 Channel A
+Pin.cpu.GPIO_EMC_39 FLEXPWM2 Channel B
+===================== ==================
+
+Submodule 0 pins for i.MX RT1052, i.MX RT1062 and i.MX RT1064:
+
+===================== ==================
+Pin Module & Channel
+===================== ==================
+Pin.cpu.GPIO_AD_B0_02 FLEXPWM1 Channel X
+Pin.cpu.GPIO_EMC_23 FLEXPWM1 Channel A
+Pin.cpu.GPIO_EMC_24 FLEXPWM1 Channel B
+Pin.cpu.GPIO_SD_B0_00 FLEXPWM1 Channel A
+Pin.cpu.GPIO_SD_B0_01 FLEXPWM1 Channel B
+Pin.cpu.GPIO_B0_06 FLEXPWM2 Channel A
+Pin.cpu.GPIO_B0_07 FLEXPWM2 Channel B
+Pin.cpu.GPIO_EMC_06 FLEXPWM2 Channel A
+Pin.cpu.GPIO_EMC_07 FLEXPWM2 Channel B
+Pin.cpu.GPIO_EMC_29 FLEXPWM3 Channel A
+Pin.cpu.GPIO_EMC_30 FLEXPWM3 Channel B
+Pin.cpu.GPIO_AD_B1_08 FLEXPWM4 Channel A
+Pin.cpu.GPIO_EMC_00 FLEXPWM4 Channel A
+Pin.cpu.GPIO_EMC_01 FLEXPWM4 Channel B
+===================== ==================
+
+Submodule 0 pins for i.MX RT1176
+
+====================== ======================
+Pin Module & Channel
+====================== ======================
+Pin.cpu.GPIO_EMC_B1_00 FLEXPWM4 Channel A (*)
+Pin.cpu.GPIO_EMC_B1_01 FLEXPWM4 Channel B (*)
+Pin.cpu.GPIO_EMC_B1_06 FLEXPWM2 Channel A (*)
+Pin.cpu.GPIO_EMC_B1_07 FLEXPWM2 Channel B (*)
+Pin.cpu.GPIO_EMC_B1_23 FLEXPWM1 Channel A (*)
+Pin.cpu.GPIO_EMC_B1_24 FLEXPWM1 Channel B (*)
+Pin.cpu.GPIO_EMC_B1_29 FLEXPWM3 Channel A (*)
+Pin.cpu.GPIO_EMC_B1_30 FLEXPWM3 Channel B (*)
+Pin.cpu.GPIO_AD_00 FLEXPWM1 Channel A
+Pin.cpu.GPIO_AD_01 FLEXPWM1 Channel B
+Pin.cpu.GPIO_AD_24 FLEXPWM2 Channel A
+Pin.cpu.GPIO_AD_25 FLEXPWM2 Channel B
+====================== ======================
+
+(*) Pin used for SDRAM
+
+ADC (analog to digital conversion)
+----------------------------------
+
+On the i.MXRT ADC functionality is available on Pins labeled 'Ann'.
+
+Use the :ref:`machine.ADC <machine.ADC>` class::
+
+ from machine import ADC
+
+ adc = ADC(Pin(32)) # create ADC object on ADC pin
+ adc.read_u16() # read value, 0-65536 across voltage range 0.0v - 3.3v
+
+The resolution of the ADC is 12 bit with 10 to 11 bit accuracy, irrespective of the
+value returned by read_u16(). If you need a higher resolution or better accuracy, use
+an external ADC.
+
+Software SPI bus
+----------------
+
+Software SPI (using bit-banging) works on all pins, and is accessed via the
+:ref:`machine.SoftSPI <machine.SoftSPI>` class. ::
+
+ from machine import Pin, SoftSPI
+
+ # construct a SoftSPI bus on the given pins
+ # polarity is the idle state of SCK
+ # phase=0 means sample on the first edge of SCK, phase=1 means the second
+ spi = SoftSPI(baudrate=100000, polarity=1, phase=0, sck=Pin(0), mosi=Pin(2), miso=Pin(4))
+
+ spi.init(baudrate=200000) # set the baudrate
+
+ spi.read(10) # read 10 bytes on MISO
+ spi.read(10, 0xff) # read 10 bytes while outputting 0xff on MOSI
+
+ buf = bytearray(50) # create a buffer
+ spi.readinto(buf) # read into the given buffer (reads 50 bytes in this case)
+ spi.readinto(buf, 0xff) # read into the given buffer and output 0xff on MOSI
+
+ spi.write(b'12345') # write 5 bytes on MOSI
+
+ buf = bytearray(4) # create a buffer
+ spi.write_readinto(b'1234', buf) # write to MOSI and read from MISO into the buffer
+ spi.write_readinto(buf, buf) # write buf to MOSI and read MISO back into buf
+
+The highest supported baud rate is 500000.
+
+Hardware SPI bus
+----------------
+
+There are up to four hardware SPI channels that allow faster transmission
+rates (up to 90Mhz). The SPI signals have fixed assignments to GPIO pins.
+It depends on the board design, which SPI's signals are exposed to the user, as
+detailed in the table below. The signal order in the table is: CS0, CS1, MOSI, MISO, CLK.
+
+================= ========================= ======================= ===============
+Board / Pin SPI0 SPI1 SPI2
+================= ========================= ======================= ===============
+Teensy 4.0 10/-/11/12/13 0/-/26/1/27 -
+Teensy 4.1 10/37/11/12/13 0/-/26/1/27 -/29/50/54/49
+MIXMXRT1010-EVK D10/D7/D11/D12/D13 - -
+MIXMXRT1015-EVK D10/-/D11/D12/D13 - -
+MIXMXRT1020-EVK D10/-/D11/D12/D13 A3/D0/A5/A4/A0 -
+MIXMXRT1050-EVK D10/-/D11/D12/D13 (*) - -
+MIXMXRT1050-EVKB D10/-/D11/D12/D13 (*) - -
+MIXMXRT1060-EVK D10/-/D11/D12/D13 (*) - -
+MIXMXRT1064-EVK D10/-/D11/D12/D13 (*) - -
+MIXMXRT1170-EVK D10/-/D11/D12/D13 D28/-/D25/D24/D26 -/-/D14/D15/D24
+Olimex RT1010Py - CS0/-/SDO/SDI/SCK SDCARD with CS1
+Seeed ARCH MIX J4_12/-/J4_14/J4_13/J4_15 J3_09/J3_05/J3_08_J3_11
+================= ========================= ======================= ===============
+
+Pins denoted with (*) are by default not wired at the board.
+
+Hardware SPI is accessed via the :ref:`machine.SPI <machine.SPI>` class and
+has the same methods as software SPI above::
+
+ from machine import SPI
+
+ spi = SPI(0, 10000000)
+ spi.write('Hello World')
+
+Notes:
+
+1. Even if the highest supported baud rate at the moment is 90 Mhz,
+ setting a baud rate will not always result in exactly that
+ frequency, especially at high baud rates.
+
+2. Sending at 90 MHz is possible, but in the tests receiving
+ only worked up to 60 MHz.
+
+Software I2C bus
+----------------
+
+Software I2C (using bit-banging) works on all output-capable pins, and is
+accessed via the :ref:`machine.SoftI2C <machine.SoftI2C>` class::
+
+ from machine import Pin, SoftI2C
+
+ i2c = SoftI2C(scl=Pin(5), sda=Pin(4), freq=100000)
+
+ i2c.scan() # scan for devices
+
+ i2c.readfrom(0x3a, 4) # read 4 bytes from device with address 0x3a
+ i2c.writeto(0x3a, '12') # write '12' to device with address 0x3a
+
+ buf = bytearray(10) # create a buffer with 10 bytes
+ i2c.writeto(0x3a, buf) # write the given buffer to the slave
+
+The highest supported freq is 400000.
+
+Hardware I2C bus
+----------------
+
+There are up to four hardware I2C channels that allow faster transmission rates
+and support the full I2C protocol. The I2C signals have fixed assignments to GPIO pins.
+It depends on the board design, which I2C's signals are exposed to the user, as
+detailed in the table below. The signal order in the table is: SDA, SCL.
+
+================= =========== =========== =========== ======= =======
+Board / Pin I2C 0 I2C 1 I2C 2 I2C 3 I2C 4
+================= =========== =========== =========== ======= =======
+Teensy 4.0 18/19 17/16 25/24 - -
+Teensy 4.1 18/19 17/16 25/24 - -
+MIXMXRT1010-EVK D14/D15 D0/D1 - - -
+MIXMXRT1015-EVK D14/D15 - - - -
+MIXMXRT1020-EVK D14/D15 A4/A5 D0/D1 - -
+MIXMXRT1050-EVK A4/A5 D1/D0 - - -
+MIXMXRT1050-EVKB A4/A5 D1/D0 - - -
+MIXMXRT1060-EVK A4/A5 D1/D0 - - -
+MIXMXRT1064-EVK A4/A5 D1/D0 - - -
+MIXMXRT1170-EVK D14/D15 D1/D0 A4/A5 D26/D25 D19/D18
+Olimex RT1010Py - SDA1/SCL1 SDA2/SCL2 - -
+Seeed ARCH MIX J3_17/J3_16 J4_06/J4_07 J5_05/J5_04 - -
+================= =========== =========== =========== ======= =======
+
+Hardware I2C is accessed via the :ref:`machine.I2C <machine.I2C>` class and
+has the same methods as software SPI above::
+
+ from machine import I2C
+
+ i2c = I2C(0, 400_000)
+ i2c.writeto(0x76, b"Hello World")
+
+I2S bus
+-------
+
+See :ref:`machine.I2S <machine.I2S>`. Example using a Teensy 4.1 board with a simple
+external Codec like UDA1334.::
+
+ from machine import I2S, Pin
+ i2s = I2S(2, sck=Pin(26), ws=Pin(27), sd=Pin(7),
+ mode=I2S.TX, bts=16,format=I2S.STEREO,
+ rate=44100,ibuf=40000)
+ i2s.write(buf) # write buffer of audio samples to I2S device
+
+
+Example for using I2S with a MIMXRT10xx_DEV board::
+
+ from machine import I2S, I2C, Pin
+ import wm8960
+
+ i2c=I2C(0)
+
+ wm=wm8960.WM8960(i2c, sample_rate=SAMPLE_RATE_IN_HZ,
+ adc_sync=wm8960.sync_dac,
+ swap=wm8960.swap_input)
+
+ i2s = I2S(1, sck=Pin("SCK_TX"), ws=Pin("WS_TX"), sd=Pin("SD_RX"),
+ mck=Pin("MCK),mode=I2S.RX, bts=16,format=I2S.MONO,
+ rate=32000,ibuf=10000)
+ i2s.readinto(buf) # fill buffer with audio samples from I2S device
+
+In this example, the input channels are swapped in the WM8960 driver, since the
+on-board microphone is connected to the right channel, but mono audio is taken
+from the left channel. Note, that the sck and ws pins are connected to the TX
+signals of the I2S bus. That is intentional, since at the MW8960 codec these
+signals are shared for RX and TX.
+
+Example using the Teensy audio shield::
+
+ from machine import I2C, I2S, Pin
+ from sgtl5000 import CODEC
+ i2s = I2S(1, sck=Pin(21), ws=Pin(20), sd=Pin(7), mck=Pin(23),
+ mode=I2S.TX, bits=16,rate=44100,format=I2S.STEREO,
+ ibuf=40000,
+ )
+
+ # configure the SGTL5000 codec
+ i2c = I2C(0, freq=400000)
+ codec = CODEC(0x0A, i2c)
+ codec.mute_dac(False)
+ codec.dac_volume(0.9, 0.9)
+ codec.headphone_select(0)
+ codec.mute_headphone(False)
+ codec.volume(0.7, 0.7)
+
+ i2s.write(buf) # write buffer of audio samples to I2S device
+
+The SGTL5000 codec used by the Teensy Audio shield uses the RX signals for both
+RX and TX. Note that the codec is initialized after the I2S device. That is
+essential since MCK is needed for its I2C operation and is provided by the I2S
+controller.
+
+MIMXRT boards may have 1 or 2 I2S buses available at the board connectors.
+On MIMXRT1010 devices the bus numbers are 1 and 3.
+
+Pin assignments for a few MIMXRT boards:
+
+=============== == ===== ======== ======= ======= ======== ======= =======
+Board ID MCK SCK_TX WS_TX SD_TX SCK_RX WS_RX SD_RX
+=============== == ===== ======== ======= ======= ======== ======= =======
+Teensy 4.0 1 23 26 27 7 21 20 8
+Teensy 4.0 2 33 4 3 2 - - 5
+Teensy 4.1 1 23 26 27 7 21 20 8
+Teensy 4.1 2 33 4 3 2 - - 5
+Seeed Arch MIX 1 J4_09 J4_14 J4_15 J14_13 J4_11 J4_10 J4_10
+Olimex RT1010Py 1 D8 D6 D7 D4 D1 D2 D3
+Olimex RT1010Py 3 - D10 D9 D11 - - -
+MIMXRT_DEV 1 "MCK" "SCK_TX" "WS_TX" "SD_TX" "SCK_RX" "WS_RX" "SD_RX"
+=============== == ===== ======== ======= ======= ======== ======= =======
+
+Symbolic pin names are provided for the MIMXRT_10xx_DEV boards.
+These are provided for the other boards as well.
+
+Real time clock (RTC)
+---------------------
+
+See :ref:`machine.RTC <machine.RTC>`::
+
+ from machine import RTC
+
+ rtc = RTC()
+ rtc.datetime((2017, 8, 23, 1, 12, 48, 0, 0)) # set a specific date and time
+ rtc.datetime() # get date and time
+ rtc.now() # return date and time in CPython format.
+
+The i.MXRT MCU supports battery backup of the RTC. By connecting a battery of
+1.5-3.6V, time and date are maintained in the absence of the main power. The
+current drawn from the battery is ~20µA, which is rather high. A CR2032 coin
+cell will last for about one year.
+
+SD card
+-------
+
+See :ref:`machine.SDCard <machine.SDCard>`::
+
+ import machine, os
+
+ sd = machine.SDCard()
+ fs = os.VfsFat(sd)
+ os.mount(fs, "/sd") # mount
+ os.listdir('/sd') # list directory contents
+ os.umount('/sd') # eject
+
+Note: The i.mx-rt 1011 and 1015 based boards do not support the ``machine.SDCard``
+class. For these, the SPI based driver ``sdcard.py`` from the MicroPython drivers
+can be used. When using it, you have to overdrive the CS pin of the SPI hardware
+module. Example::
+
+ import os, sdcard, machine
+
+ cs_pin = "D10"
+ spi = machine.SPI(0) # SPI0 with cs at Pin "D10" used for SDCARD
+ cs = machine.Pin(cs_pin, machine.Pin.OUT, value=1)
+ sd = sdcard.SDCard(spi, cs)
+ vfs = os.VfsFat(sd)
+ os.mount(vfs, "/sdcard")
+
+OneWire driver
+--------------
+
+The OneWire driver is implemented in software and works on all pins::
+
+ from machine import Pin
+ import onewire
+
+ ow = onewire.OneWire(Pin(12)) # create a OneWire bus on GPIO12
+ ow.scan() # return a list of devices on the bus
+ ow.reset() # reset the bus
+ ow.readbyte() # read a byte
+ ow.writebyte(0x12) # write a byte on the bus
+ ow.write('123') # write bytes on the bus
+ ow.select_rom(b'12345678') # select a specific device by its ROM code
+
+There is a specific driver for DS18S20 and DS18B20 devices::
+
+ import time, ds18x20
+ ds = ds18x20.DS18X20(ow)
+ roms = ds.scan()
+ ds.convert_temp()
+ time.sleep_ms(750)
+ for rom in roms:
+ print(ds.read_temp(rom))
+
+Be sure to put a 4.7k pull-up resistor on the data line. Note that
+the ``convert_temp()`` method must be called each time you want to
+sample the temperature.
+
+DHT driver
+----------
+
+The DHT driver is implemented in software and works on all pins::
+
+ import dht
+ import machine
+
+ d = dht.DHT11(machine.Pin(4))
+ d.measure()
+ d.temperature() # eg. 23 (°C)
+ d.humidity() # eg. 41 (% RH)
+
+ d = dht.DHT22(machine.Pin(4))
+ d.measure()
+ d.temperature() # eg. 23.6 (°C)
+ d.humidity() # eg. 41.3 (% RH)
+
+Be sure to have a 4.7k pull-up resistor on the data line. Some
+DHT modules may already have one.
+
+Ethernet driver
+---------------
+
+All MIMXRT boards except the MIMXRT1011 based boards and Teensy 4.0 support
+Ethernet. Example usage::
+
+ import network
+
+ lan = network.LAN(0)
+ lan.active(True)
+
+If there is a DHCP server in the LAN, the IP address is supplied by that server.
+Otherwise, the IP address can be set with lan.ifconfig(). The default address
+is 192.168.0.1.
+
+Teensy 4.1 does not have an Ethernet jack on the board, but PJRC offers an
+adapter for self-assembly. The Seeed ARCH MIX board has no PHY hardware on the
+board, however you can attach external PHY interfaces. By default, the firmware
+for Seeed Arch Mix uses the driver for a LAN8720 PHY. The MIMXRT1170_EVK is
+equipped with two Ethernet ports, which are addressed as LAN(0) for the 100M
+port and LAN(1) for the 1G port.
+
+For details of the network interface refer to the class :ref:`network.LAN <network.LAN>`.
+
+Transferring files
+------------------
+
+Files can be transferred to the i.MXRT devices for instance with the ``mpremote``
+tool or using an SD card. If Ethernet is available, you can also use ftp.
+See the MicroPython forum for the FTP server or other community-supported
+alternatives to transfer files to an i.MXRT board, like rshell or Thonny.