Not able to use UART1 in STM32MP135F-DK board

[SteMMo]

Hi all,

I own a STM32MP135F-DK board and  started to write a simple firmware on it based on RTX threads.

I'd like to use USART1 port as simple terminal interface with the board.

I chose USART1 cause it is present on CN8 connector (RX + TX) and cause the UART8 presents only TX pin.

The code I wrote is:

 

 

void MX_USART1_UART_Init(void)
{
	huart1.Instance = USART1;
	huart1.Init.BaudRate = 9600;
	huart1.Init.WordLength = UART_WORDLENGTH_8B;
	huart1.Init.StopBits = UART_STOPBITS_1;
	huart1.Init.Parity = UART_PARITY_NONE;
	huart1.Init.Mode = UART_MODE_TX_RX;
	huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
	huart1.Init.OverSampling = UART_OVERSAMPLING_16;
	if (HAL_UART_Init(&huart1) != HAL_OK)
	{
		ASSERT(false);
	}
}

 

 

and

 

 

	if (uartHandle->Instance == USART1)
	{
		/* USER CODE BEGIN USART1_MspInit 0 */

		/* USER CODE END USART1_MspInit 0 */
		/* USART1 clock enable */
		__HAL_RCC_USART1_CLK_ENABLE();

		__HAL_RCC_GPIOB_CLK_ENABLE();
		__HAL_RCC_GPIOC_CLK_ENABLE();
		/**USART1 GPIO Configuration
		PC2 ------> USART1_RTS
		PC0 ------> USART1_TX
		PB0 ------> USART1_RX
		*/
		GPIO_InitStruct.Pin = GPIO_PIN_0 | GPIO_PIN_2;
		GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
		GPIO_InitStruct.Pull = GPIO_NOPULL;
		GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
		HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

		GPIO_InitStruct.Pin = GPIO_PIN_0;
		GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
		GPIO_InitStruct.Pull = GPIO_NOPULL;
		GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
		GPIO_InitStruct.Alternate = GPIO_AF4_USART1;
		HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

		/* USART3 interrupt Init */
		GIC_SetPriority(USART1_IRQn, 0);
		GIC_EnableIRQ(USART1_IRQn);
		/* USER CODE BEGIN USART1_MspInit 1 */

		/* USER CODE END USART1_MspInit 1 */
	}

 

 

I'm wondering if this code is correct cause, connecting to the CN8 pins a 232-USB FTDI232 converter I see nothing on the terminal running on Windows.

If I comment out the GIC_EnableIRQ() lines the firmware continue to run (without any serial output): I see the firmware is alive cause a task that blinks red and blue LEDS.

If I leave the IRQ (and I transmit something) the LEDs task freeze and if I press pause IDE button I almost always land in the IRQ_EndOfInterrupt() function (or nearby - irqarmv7a.S), with irqn=70 (USART1_IRQn).

If I try with UART8 I  have the same behaviors but irqn=116 (UART8_IRQn).

Any idea, please?

 

 

[SteMMo]

Partial solutions:

UART8:

• removed the __HAL_RCC_GPIOx_ENABLE() macros
• added the UART8_IRQHandler() to overwrite the empty default function

This way I'm able to receive on Windows side the output. But on the CN8 connector there is not the UART8_RX pin.

UART1: applied the same changes. The UART1_IRQHandler() only receives FRAME_ERROR irq.

 

[SteMMo]

Following the UART8 way, I wrote some functions to handle the debug outputs toward UART8.

The source is:

 

/*
 * serial_dbg.c
 *
 * Created on: Sep 4, 2024
 *
 */

#include <stdio.h>
#include <stdarg.h>
#include "system.h"
#include "stm32mp13xx_it.h"
#include "serial_dbg.h"


#define DBGMSG_MAX_STRING_LENGTH		128


static UART_HandleTypeDef huartDbg;
static __IO ITStatus UartReady = RESET;



void serial_dbg_output(const char *format, ...)
{
	static va_list args;
	static uint32_t length;

	if (huartDbg.Instance == 0)	
		return;

	char Trace_Buffer[DBGMSG_MAX_STRING_LENGTH + 1];

	va_start(args, format); //lint !e718 !e727 !e746 !e530
	length = vsnprintf(Trace_Buffer, sizeof(Trace_Buffer), format, args);
	if (length > DBGMSG_MAX_STRING_LENGTH)
	{
		length = DBGMSG_MAX_STRING_LENGTH;
		Trace_Buffer[DBGMSG_MAX_STRING_LENGTH - 2] = '.';
		Trace_Buffer[DBGMSG_MAX_STRING_LENGTH - 1] = '.';
		Trace_Buffer[DBGMSG_MAX_STRING_LENGTH] = '\0';
	}
	va_end(args); //lint !e718 !e746

	if(HAL_UART_Transmit_IT(&huartDbg, (uint8_t*)Trace_Buffer, length)!= HAL_OK)
	{
	 Error_Handler();
	}

	while (UartReady != SET){}

	/* Reset transmission flag */
	UartReady = RESET;
}


/* UARTDbg init function */
static void MX_UARTDbg_Init(void)
{
	huartDbg.Instance = UART8;
	huartDbg.Init.BaudRate = 9600;
	huartDbg.Init.WordLength = UART_WORDLENGTH_8B;
	huartDbg.Init.StopBits = UART_STOPBITS_1;
	huartDbg.Init.Parity = UART_PARITY_NONE;
	huartDbg.Init.Mode = UART_MODE_TX_RX;
 huartDbg.Init.HwFlowCtl = UART_HWCONTROL_NONE;
 huartDbg.Init.OverSampling = UART_OVERSAMPLING_16;
 huartDbg.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
 huartDbg.Init.ClockPrescaler = UART_PRESCALER_DIV1;
 huartDbg.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
 if (HAL_UART_Init(&huartDbg) != HAL_OK)
 {
 Error_Handler();
 }

 if (HAL_UARTEx_SetTxFifoThreshold(&huartDbg, UART_TXFIFO_THRESHOLD_1_8) != HAL_OK)
 {
 Error_Handler();
 }

 if (HAL_UARTEx_SetRxFifoThreshold(&huartDbg, UART_RXFIFO_THRESHOLD_1_8) != HAL_OK)
 {
 Error_Handler();
 }

 if (HAL_UARTEx_DisableFifoMode(&huartDbg) != HAL_OK)
 {
 Error_Handler();
 }

}


/*
 */
void serial_dbg_init()
{
	char initMsg[] = "-- DEBUG STARTED --\r\n";

	MX_UARTDbg_Init();
	serial_dbg_output(initMsg);
}



void UART8_IRQHandler(void)
{
 HAL_UART_IRQHandler(&huartDbg);
}


void HAL_UART_TxCpltCallback(UART_HandleTypeDef *UartHandle)
{
 /* Set transmission flag: transfer complete */
 UartReady = SET;
}

 

The functions are callled within application_init() function, generating some debug outputs between some init functions.

Now it happens that, after the call to serial_dbg_init(), if I call a function that contains a task creation, for example

 

	Usb_App_Thread_Id = osThreadNew(usb_app_task, NULL, &Usb_App_Thread_Attributes);

 

the firmware hangs.

WhenI press pause button, I land in an infinite loop (while(1);) inside the CUndefHandler() function in the file RTX/Src/handlers.c, calld by Undef_Handler() in RTX/Src/irq_armv7a.S

Without the serial_dbg_init() call there are not problems.

Any idea?

[debugging]

Is this bare metal programming and the STM32MP13 or using Linux ?

[SteMMo]

It is a bare metal programming.

I've found the working UART1 configurations:

 

		GPIO_InitStruct.Pin = GPIO_PIN_0;
		GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
		GPIO_InitStruct.Pull = GPIO_NOPULL;
		GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
		GPIO_InitStruct.Alternate = GPIO_AF7_USART1;
		HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

		GPIO_InitStruct.Pin = GPIO_PIN_0;
		GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
		GPIO_InitStruct.Pull = GPIO_PULLUP;
		GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
		GPIO_InitStruct.Alternate = GPIO_AF4_USART1;
		HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

 

In general, whare I can find the possible pins configuration, including the alternate modes?

Thanks!

[PatrickF]

Hi @SteMMo ,

 

---

@SteMMo wrote:

In general, whare I can find the possible pins configuration, including the alternate modes?

---

 

Information is present in product Datasheet or in a more friendly way using STM32CubeMx.

Regards.