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STM32L4: Support more UARTs #41

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5cadb2f
Support more UARTs
xarantolus Mar 26, 2026
f0c1e65
Cleanup
xarantolus Mar 26, 2026
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98 changes: 63 additions & 35 deletions machine/arm/stm32l4xx/interface/uart.c
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Original file line number Diff line number Diff line change
Expand Up @@ -33,52 +33,80 @@ int write_debug_uart(const char *buf, int len) {
}

void HAL_UART_MspInit(UART_HandleTypeDef *huart) {
if (huart->Instance == LPUART1) {

RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_LPUART1;
PeriphClkInit.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_PCLK1;

if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK) {
return;
}

__HAL_RCC_LPUART1_CLK_ENABLE();
RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
GPIO_InitTypeDef GPIO_InitStruct = {0};
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;

if (huart->Instance == USART1) {
// TX: PA9 (AF7), RX: PA10 (AF7)
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USART1;
PeriphClkInit.Usart1ClockSelection = RCC_USART1CLKSOURCE_PCLK2;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK) return;
__HAL_RCC_USART1_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
GPIO_InitStruct.Alternate = GPIO_AF7_USART1;
GPIO_InitStruct.Pin = GPIO_PIN_9 | GPIO_PIN_10;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

} else if (huart->Instance == USART2) {
// TX: PA2 (AF7), RX: PA3 (AF7)
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USART2;
PeriphClkInit.Usart2ClockSelection = RCC_USART2CLKSOURCE_PCLK1;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK) return;
__HAL_RCC_USART2_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
GPIO_InitStruct.Alternate = GPIO_AF7_USART2;
GPIO_InitStruct.Pin = GPIO_PIN_2 | GPIO_PIN_3;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

} else if (huart->Instance == USART3) {
// TX: PC10 (AF7), RX: PC11 (AF7)
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USART3;
PeriphClkInit.Usart3ClockSelection = RCC_USART3CLKSOURCE_PCLK1;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK) return;
__HAL_RCC_USART3_CLK_ENABLE();
__HAL_RCC_GPIOC_CLK_ENABLE();
GPIO_InitStruct.Alternate = GPIO_AF7_USART3;
GPIO_InitStruct.Pin = GPIO_PIN_10 | GPIO_PIN_11;
HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

GPIO_InitTypeDef GPIO_InitStruct = {0};
GPIO_InitStruct.Pin = GPIO_PIN_6 | GPIO_PIN_7; // LPUART1_TX, LPUART1_RX
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
GPIO_InitStruct.Alternate = GPIO_AF8_LPUART1;
} else if (huart->Instance == UART4) {
// TX: PA0 (AF8), RX: PA1 (AF8)
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_UART4;
PeriphClkInit.Uart4ClockSelection = RCC_UART4CLKSOURCE_PCLK1;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK) return;
__HAL_RCC_UART4_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
GPIO_InitStruct.Alternate = GPIO_AF8_UART4;
GPIO_InitStruct.Pin = GPIO_PIN_0 | GPIO_PIN_1;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

HAL_PWREx_EnableVddIO2();
__HAL_RCC_GPIOG_CLK_ENABLE();
HAL_GPIO_Init(GPIOG, &GPIO_InitStruct);
} else if (huart->Instance == UART5) {

RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
// TX: PC12 (AF8), RX: PD2 (AF8)
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_UART5;
PeriphClkInit.Uart5ClockSelection = RCC_UART5CLKSOURCE_PCLK1;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK) {
return;
}

if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK) return;
__HAL_RCC_UART5_CLK_ENABLE();

// Enable GPIO clocks
HAL_PWREx_EnableVddIO2();
__HAL_RCC_GPIOC_CLK_ENABLE();
__HAL_RCC_GPIOD_CLK_ENABLE();

GPIO_InitTypeDef GPIO_InitStruct = {0};
GPIO_InitStruct.Pin = GPIO_PIN_12; // PC12 == UART5_TX
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
GPIO_InitStruct.Alternate = GPIO_AF8_UART5;
GPIO_InitStruct.Pin = GPIO_PIN_12;
HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
// PD2 == UART5_RX
GPIO_InitStruct.Pin = GPIO_PIN_2;
HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);

} else if (huart->Instance == LPUART1) {
// TX: PG7 (AF8), RX: PG8 (AF8)
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_LPUART1;
PeriphClkInit.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_PCLK1;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK) return;
__HAL_RCC_LPUART1_CLK_ENABLE();
HAL_PWREx_EnableVddIO2();
__HAL_RCC_GPIOG_CLK_ENABLE();
GPIO_InitStruct.Alternate = GPIO_AF8_LPUART1;
GPIO_InitStruct.Pin = GPIO_PIN_7 | GPIO_PIN_8;
HAL_GPIO_Init(GPIOG, &GPIO_InitStruct);
}
}
2 changes: 1 addition & 1 deletion options.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,7 @@ type = "Boolean"
[debug.uart]
name = "Debug UART"
description = "Select the UART peripheral to use for debug output."
type = { type = "String", allowed_values = ["LPUART1", "UART5"] }
type = { type = "String", allowed_values = ["USART1", "USART2", "USART3", "UART4", "UART5", "LPUART1"] }
default = "LPUART1"

[tuning]
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