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STM32L0/4 Enable use of LPUART in stop mode #5941

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Merged
merged 2 commits into from
Feb 12, 2018
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STM32L0/4 Enable use of LPUART in stop mode #5941

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01660ff
STM32L0/4: Always try to select LSE if LPUART and baudrate <= 9600
Jan 25, 2018
7881e68
STM32L0: Enable stop mode operation for the LPUART
Jan 25, 2018
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54 changes: 32 additions & 22 deletions targets/TARGET_STM/serial_api.c
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Original file line number Diff line number Diff line change
Expand Up @@ -369,32 +369,30 @@ void serial_baud(serial_t *obj, int baudrate)
struct serial_s *obj_s = SERIAL_S(obj);

obj_s->baudrate = baudrate;
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@bcostm bcostm Jan 31, 2018 •
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Not related to this PR, but maybe put back the previous baudrate if the init_uart function has returned a FAIL ?

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We could but it still doesn't really notify you that the operation has failed. You would have to check wat the actual baudrate is after te operation to verify it succeeded.

if (init_uart(obj) != HAL_OK) {

#if defined(LPUART1_BASE)
/* Note that LPUART clock source must be in the range [3 x baud rate, 4096 x baud rate], check Ref Manual */
if (obj_s->uart == LPUART_1) {
/* Try to change LPUART clock source */
RCC_PeriphCLKInitTypeDef PeriphClkInitStruct = {0};
if (baudrate == 9600) {
PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_LPUART1;
PeriphClkInitStruct.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_LSE;
HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct);
if (init_uart(obj) == HAL_OK){
return;
}
}
else {
PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_LPUART1;
PeriphClkInitStruct.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_SYSCLK;
HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct);
if (init_uart(obj) == HAL_OK){
return;
}
}
if (obj_s->uart == LPUART_1) {
/* If baudrate is lower than 9600 try to change to LSE */
RCC_PeriphCLKInitTypeDef PeriphClkInitStruct = {0};
if (baudrate <= 9600 && __HAL_RCC_GET_FLAG(RCC_FLAG_LSERDY)) {
PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_LPUART1;
PeriphClkInitStruct.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_LSE;
HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct);
} else {
PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_LPUART1;
PeriphClkInitStruct.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_PCLK1;
HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct);
}
if (init_uart(obj) == HAL_OK) {
return;
}
/* Change LPUART clock source and try again */
PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_LPUART1;
PeriphClkInitStruct.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_SYSCLK;
HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct);
}
#endif /* LPUART1_BASE */

if (init_uart(obj) != HAL_OK) {
debug("Cannot initialize UART with baud rate %u\n", baudrate);
}
}
Expand Down Expand Up @@ -527,6 +525,18 @@ HAL_StatusTypeDef init_uart(serial_t *obj)
huart->Init.Mode = UART_MODE_TX_RX;
}

#if defined(LPUART1_BASE)
if (huart->Instance == LPUART1) {
if (obj_s->baudrate <= 9600) {
HAL_UARTEx_EnableClockStopMode(huart);
HAL_UARTEx_EnableStopMode(huart);
} else {
HAL_UARTEx_DisableClockStopMode(huart);
HAL_UARTEx_DisableStopMode(huart);
}
}
#endif

return HAL_UART_Init(huart);
}

Expand Down