1.. _module-pw_sys_io_stm32cube: 2 3------------------- 4pw_sys_io_stm32cube 5------------------- 6 7``pw_sys_io_stm32cube`` implements the ``pw_sys_io`` facade over UART using 8the STM32Cube HAL to support an assortment of boards from STMicroelectronics. 9 10The UART baud rate is fixed at 115200 (8N1). 11 12Setup 13===== 14This module requires relatively minimal setup: 15 16 1. Write code against the ``pw_sys_io`` facade. 17 2. Specify the ``dir_pw_sys_io_backend`` GN global variable to point to this 18 backend. 19 3. Call ``pw_sys_io_Init()`` during init so the UART is properly initialized 20 and configured. 21 22For devices other than the STM32F429I-DISC1, this module will need to be 23configured to use the appropriate GPIO pins and USART peripheral. 24 25Module Configuration Options 26============================ 27The following configurations can be adjusted via compile-time configuration of 28this module, see the 29:ref:`module documentation <module-structure-compile-time-configuration>` for 30more details. 31 32.. c:macro:: PW_SYS_IO_STM32CUBE_USART_NUM 33 34 The USART peripheral number to use. (1 for USART1, 2 for USART2, etc.) 35 36.. c:macro:: PW_SYS_IO_STM32CUBE_GPIO_PORT 37 38 The port that the USART peripheral TX/RX pins are on. (e.g. to use A9/A10 39 pins for TX and RX, respectively, set this to A) 40 41.. c:macro:: PW_SYS_IO_STM32CUBE_GPIO_TX_PORT 42 43 The port for the USART peripheral TX pin, if different from 44 PW_SYS_IO_STM32CUBE_GPIO_PORT. 45 46.. c:macro:: PW_SYS_IO_STM32CUBE_GPIO_RX_PORT 47 48 The port for the USART peripheral RX pin, if different from 49 PW_SYS_IO_STM32CUBE_GPIO_PORT. 50 51.. c:macro:: PW_SYS_IO_STM32CUBE_GPIO_TX_PIN 52 53 The pin index to use for USART transmission within the port set by 54 ``PW_SYS_IO_STM32CUBE_GPIO_PORT``. 55 56.. c:macro:: PW_SYS_IO_STM32CUBE_GPIO_RX_PIN 57 58 The pin index to use for USART reception within the port set by 59 ``PW_SYS_IO_STM32CUBE_GPIO_PORT``. 60 61.. c:macro:: PW_SYS_IO_STM32CUBE_GPIO_AF 62 63 The alternate function index to use for USART reception within the port set by 64 ``PW_SYS_IO_STM32CUBE_GPIO_PORT``. 65 66.. c:macro:: PW_SYS_IO_STM32CUBE_USART_PREFIX 67 68 The peripheral name prefix (either UART or USART) for the peripheral selected 69 by ``PW_SYS_IO_STM32CUBE_USART_NUM``. Defaults to USART. 70 71Module usage 72============ 73After building an executable that utilizes this backend, flash the 74produced .elf binary to the development board. Then, using a serial 75communication terminal like minicom/screen (Linux/Mac) or TeraTerm (Windows), 76connect to the device at a baud rate of 115200 (8N1). If you're not using a 77STM32F429I-DISC1 development board, manually connect a USB-to-serial TTL adapter 78to pins ``PA9`` (MCU TX) and ``PA10`` (MCU RX), making sure to match logic 79levels (e.g. 3.3V versus 1.8V). 80 81Sample connection diagram 82------------------------- 83 84.. code-block:: text 85 86 --USB Serial--+ +-----STM32F429 MCU----- 87 | | 88 TX o--->o PA10/USART1_RX 89 | | 90 RX o<---o PA9/USART1_TX 91 | | 92 --------------+ +----------------------- 93