.. currentmodule:: stm :mod:`stm` --- functionality specific to STM32 MCUs =================================================== .. module:: stm :synopsis: functionality specific to STM32 MCUs This module provides functionality specific to STM32 microcontrollers, including direct access to peripheral registers. Memory access ------------- The module exposes three objects used for raw memory access. .. data:: mem8 Read/write 8 bits of memory. .. data:: mem16 Read/write 16 bits of memory. .. data:: mem32 Read/write 32 bits of memory. Use subscript notation ``[...]`` to index these objects with the address of interest. These memory objects can be used in combination with the peripheral register constants to read and write registers of the MCU hardware peripherals, as well as all other areas of address space. Peripheral register constants ----------------------------- The module defines constants for registers which are generated from CMSIS header files, and the constants available depend on the microcontroller series that is being compiled for. Examples of some constants include: .. data:: GPIOA Base address of the GPIOA peripheral. .. data:: GPIOB Base address of the GPIOB peripheral. .. data:: GPIO_BSRR Offset of the GPIO bit set/reset register. .. data:: GPIO_IDR Offset of the GPIO input data register. .. data:: GPIO_ODR Offset of the GPIO output data register. Constants that are named after a peripheral, like ``GPIOA``, are the absolute address of that peripheral. Constants that have a prefix which is the name of a peripheral, like ``GPIO_BSRR``, are relative offsets of the register. Accessing peripheral registers requires adding the absolute base address of the peripheral and the relative register offset. For example ``GPIOA + GPIO_BSRR`` is the full, absolute address of the ``GPIOA->BSRR`` register. Example use: .. code-block:: python3 # set PA2 high stm.mem32[stm.GPIOA + stm.GPIO_BSRR] = 1 << 2 # read PA3 value = (stm.mem32[stm.GPIOA + stm.GPIO_IDR] >> 3) & 1 Functions specific to STM32WBxx MCUs ------------------------------------ These functions are available on STM32WBxx microcontrollers, and interact with the second CPU, the RF core. .. function:: rfcore_status() Returns the status of the second CPU as an integer (the first word of device info table). .. function:: rfcore_fw_version(id) Get the version of the firmware running on the second CPU. Pass in 0 for *id* to get the FUS version, and 1 to get the WS version. Returns a 5-tuple with the full version number. .. function:: rfcore_sys_hci(ogf, ocf, data, timeout_ms=0) Execute a HCI command on the SYS channel. The execution is synchronous. Returns a bytes object with the result of the SYS command. Functions specific to STM32WLxx MCUs ------------------------------------ These functions are available on STM32WLxx microcontrollers, and interact with the integrated "SUBGHZ" radio modem peripheral. .. function:: subghz_cs(level) Sets the internal SPI CS pin attached to the radio peripheral. The ``level`` argument is active-low: a truthy value means "CS pin high" and de-asserts the signal, a falsey value means "CS pin low" and asserts the signal. The internal-only SPI bus corresponding to this CS signal can be instantiated using :ref:`machine.SPI()` ``id`` value ``"SUBGHZ"``. .. function:: subghz_irq(handler) Sets the internal SUBGHZ radio interrupt handler to the provided function. The handler function is called as a "hard" interrupt in response to radio peripheral interrupts. See :ref:`isr_rules` for more information about interrupt handlers in MicroPython. Calling this function with the handler argument set to None disables the IRQ. Due to a hardware limitation, each time this IRQ fires MicroPython disables it before calling the handler. In order to receive another interrupt, Python code should call ``subghz_irq()`` to set the handler again. This has the side effect of re-enabling the IRQ. .. function:: subghz_is_busy() Return a ``bool`` corresponding to the internal "RFBUSYS" signal from the radio peripheral. Before sending a new command to the radio over SPI then this function should be polled until it returns ``False``, to confirm the busy signal is de-asserted.