pw_sys_io_stm32cube#

pw_sys_io_stm32cube implements the pw_sys_io facade over UART using the STM32Cube HAL to support an assortment of boards from STMicroelectronics.

The UART baud rate is fixed at 115200 (8N1).

Setup#

This module requires relatively minimal setup:

  1. Write code against the pw_sys_io facade.

  2. Specify the dir_pw_sys_io_backend GN global variable to point to this backend.

  3. Call pw_sys_io_Init() during init so the UART is properly initialized and configured.

For devices other than the STM32F429I-DISC1, this module will need to be configured to use the appropriate GPIO pins and USART peripheral.

Module Configuration Options#

The following configurations can be adjusted via compile-time configuration of this module, see the module documentation for more details.

PW_SYS_IO_STM32CUBE_USART_NUM#

The USART peripheral number to use. (1 for USART1, 2 for USART2, etc.)

PW_SYS_IO_STM32CUBE_GPIO_PORT#

The port that the USART peripheral TX/RX pins are on. (e.g. to use A9/A10 pins for TX and RX, respectively, set this to A)

PW_SYS_IO_STM32CUBE_GPIO_TX_PORT#

The port for the USART peripheral TX pin, if different from PW_SYS_IO_STM32CUBE_GPIO_PORT.

PW_SYS_IO_STM32CUBE_GPIO_RX_PORT#

The port for the USART peripheral RX pin, if different from PW_SYS_IO_STM32CUBE_GPIO_PORT.

PW_SYS_IO_STM32CUBE_GPIO_TX_PIN#

The pin index to use for USART transmission within the port set by PW_SYS_IO_STM32CUBE_GPIO_PORT.

PW_SYS_IO_STM32CUBE_GPIO_RX_PIN#

The pin index to use for USART reception within the port set by PW_SYS_IO_STM32CUBE_GPIO_PORT.

PW_SYS_IO_STM32CUBE_GPIO_AF#

The alternate function index to use for USART reception within the port set by PW_SYS_IO_STM32CUBE_GPIO_PORT.

PW_SYS_IO_STM32CUBE_GPIO_REMAP#

Remap alternate function for USART reception (either ENABLE or DISABLE). It only applies to the stm32f1xx family.

PW_SYS_IO_STM32CUBE_USART_PREFIX#

The peripheral name prefix (either UART or USART) for the peripheral selected by PW_SYS_IO_STM32CUBE_USART_NUM. Defaults to USART.

Module usage#

After building an executable that utilizes this backend, flash the produced .elf binary to the development board. Then, using a serial communication terminal like minicom/screen (Linux/Mac) or TeraTerm (Windows), connect to the device at a baud rate of 115200 (8N1). If you’re not using a STM32F429I-DISC1 development board, manually connect a USB-to-serial TTL adapter to pins PA9 (MCU TX) and PA10 (MCU RX), making sure to match logic levels (e.g. 3.3V versus 1.8V).

Sample connection diagram#

--USB Serial--+    +-----STM32F429 MCU-----
              |    |
           TX o--->o PA10/USART1_RX
              |    |
           RX o<---o PA9/USART1_TX
              |    |
--------------+    +-----------------------
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