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STM32: add lpuart_clock_source config #7326

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merged 2 commits into from Jun 30, 2018
Merged

STM32: add lpuart_clock_source config #7326

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9be8541
STM32: add lpuart_clock_source config
bcostm Jun 20, 2018
0c417ab
astyle
bcostm Jun 29, 2018
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35 changes: 27 additions & 8 deletions targets/TARGET_STM/serial_api.c
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Expand Up @@ -32,6 +32,11 @@

#include "serial_api_hal.h"

// Possible choices of the LPUART_CLOCK_SOURCE configuration set in json file
#define USE_LPUART_CLK_LSE 0x01
#define USE_LPUART_CLK_PCLK1 0x02
#define USE_LPUART_CLK_HSI 0x04

int stdio_uart_inited = 0; // used in platform/mbed_board.c and platform/mbed_retarget.cpp
serial_t stdio_uart;

Expand Down Expand Up @@ -367,29 +372,43 @@ void serial_baud(serial_t *obj, int baudrate)
struct serial_s *obj_s = SERIAL_S(obj);

obj_s->baudrate = baudrate;

#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) {
/* If baudrate is lower than 9600 try to change to LSE */
RCC_PeriphCLKInitTypeDef PeriphClkInitStruct = {0};
PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_LPUART1;
#if ((MBED_CONF_TARGET_LPUART_CLOCK_SOURCE) & USE_LPUART_CLK_LSE)
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;
}
}
#endif
#if ((MBED_CONF_TARGET_LPUART_CLOCK_SOURCE) & USE_LPUART_CLK_PCLK1)
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;
#endif
#if ((MBED_CONF_TARGET_LPUART_CLOCK_SOURCE) & USE_LPUART_CLK_HSI)
if (__HAL_RCC_GET_FLAG(RCC_FLAG_HSIRDY)) {
PeriphClkInitStruct.Lpuart1ClockSelection = RCC_LPUART1CLKSOURCE_HSI;
HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct);
if (init_uart(obj) == HAL_OK) {
return;
}
}
#endif
// Last chance using SYSCLK
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
4 changes: 4 additions & 0 deletions targets/targets.json
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Expand Up @@ -730,6 +730,10 @@
"help": "Define if a Low Speed External xtal (LSE) is available on the board (0 = No, 1 = Yes). If Yes, the LSE will be used to clock the RTC, LPUART, ... otherwise the Low Speed Internal clock (LSI) will be used",
"value": "1"
},
"lpuart_clock_source": {
"help": "Define the LPUART clock source. Mask values: USE_LPUART_CLK_LSE, USE_LPUART_CLK_PCLK1, USE_LPUART_CLK_HSI",
"value": "USE_LPUART_CLK_LSE|USE_LPUART_CLK_PCLK1"
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Should this also list USE_LPUART_CLK_HSI?

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I did it on purpose to not change the actual behavior. If the HSI is added here then it has also to be added in the system clock source selection. And it is not the case for all the boards... That's why I didn't add it here...

},
"stdio_uart_tx": {
"help": "default TX STDIO pins is defined in PinNames.h file, but it can be overridden"
},
Expand Down