101 lines
3.1 KiB
Markdown
101 lines
3.1 KiB
Markdown
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# The RP2 port
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This is a port of MicroPython to the Raspberry Pi RP2 series of microcontrollers.
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Currently supported features are:
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- REPL over USB VCP, and optionally over UART (on GP0/GP1).
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- Filesystem on the internal flash, using littlefs2.
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- Support for native code generation and inline assembler.
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- `utime` module with sleep, time and ticks functions.
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- `uos` module with VFS support.
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- `machine` module with the following classes: `Pin`, `ADC`, `PWM`, `I2C`, `SPI`,
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`SoftI2C`, `SoftSPI`, `Timer`, `UART`, `WDT`.
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- `rp2` module with programmable IO (PIO) support.
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See the `examples/rp2/` directory for some example code.
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## Building
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The MicroPython cross-compiler must be built first, which will be used to
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pre-compile (freeze) built-in Python code. This cross-compiler is built and
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run on the host machine using:
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$ make -C mpy-cross
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This command should be executed from the root directory of this repository.
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All other commands below should be executed from the ports/rp2/ directory.
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Building of the RP2 firmware is done entirely using CMake, although a simple
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Makefile is also provided as a convenience. To build the firmware run (from
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this directory):
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$ make clean
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$ make
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You can also build the standard CMake way. The final firmware is found in
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the top-level of the CMake build directory (`build` by default) and is
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called `firmware.uf2`.
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## Deploying firmware to the device
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Firmware can be deployed to the device by putting it into bootloader mode
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(hold down BOOTSEL while powering on or resetting) and then copying
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`firmware.uf2` to the USB mass storage device that appears.
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If MicroPython is already installed then the bootloader can be entered by
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executing `import machine; machine.bootloader()` at the REPL.
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## Sample code
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The following samples can be easily run on the board by entering paste mode
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with Ctrl-E at the REPL, then cut-and-pasting the sample code to the REPL, then
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executing the code with Ctrl-D.
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### Blinky
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This blinks the on-board LED on the Pico board at 1.25Hz, using a Timer object
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with a callback.
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```python
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from machine import Pin, Timer
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led = Pin(25, Pin.OUT)
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tim = Timer()
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def tick(timer):
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global led
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led.toggle()
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tim.init(freq=2.5, mode=Timer.PERIODIC, callback=tick)
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```
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### PIO blinky
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This blinks the on-board LED on the Pico board at 1Hz, using a PIO peripheral and
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PIO assembler to directly toggle the LED at the required rate.
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```python
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from machine import Pin
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import rp2
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@rp2.asm_pio(set_init=rp2.PIO.OUT_LOW)
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def blink_1hz():
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# Turn on the LED and delay, taking 1000 cycles.
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set(pins, 1)
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set(x, 31) [6]
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label("delay_high")
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nop() [29]
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jmp(x_dec, "delay_high")
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# Turn off the LED and delay, taking 1000 cycles.
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set(pins, 0)
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set(x, 31) [6]
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label("delay_low")
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nop() [29]
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jmp(x_dec, "delay_low")
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# Create StateMachine(0) with the blink_1hz program, outputting on Pin(25).
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sm = rp2.StateMachine(0, blink_1hz, freq=2000, set_base=Pin(25))
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sm.active(1)
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```
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See the `examples/rp2/` directory for further example code.
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