How to use printf

[syedhashmiraza]

hey how to use printf in stm32f429i-disc1 board and my mcu is stm32f103cbt6

[STTwo-32]

Hello @syedhashmiraza and welcome to the ST Community :smiling_face_with_smiling_eyes:.

I suggest you to take a look at this article. It should be helpful.

Best Regards.

STTwo-32 

[syedhashmiraza]

hey how to use printf in stm32f429i-disc1 board and my mcu is stm32f103cbt6

[Andrew Neil]

as @STTwo-32 already said, see this article:

https://community.st.com/t5/stm32-mcus/how-to-redirect-the-printf-function-to-a-uart-for-debug-messages/ta-p/49865

And here's a 3rd-party article on the same:

https://shawnhymel.com/1873/ 

Tip:

Get the basic direct UART output working before adding the printf stuff. 

[Andrew Neil]

---

@syedhashmiraza wrote:

 in stm32f429i-disc1 board and my mcu is stm32f103cbt6

---

That doesn't make sense!

As its name suggests, the stm32f429i-disc1 board contains an stm32f429i microcontroller - not an stm32f103cbt6.

But, anyhow, the method to get printf working is the same irrespective of what microcontroller you use.

[syedhashmiraza]

iam using stm32f429i-disc1 microcontroller for debug reason how to use printf

[syedhashmiraza]

i treid this one but still printf is not working

[Tesla DeLorean]

Do you have USART output working? Via HAL_UART_Transmit()

Show code.

Plumb that into __io_putchar() or syscalls/_write()

[syedhashmiraza]

#include "main.h"

#include "cmsis_os.h"

#include "usb_host.h"

#include <stdio.h>

void SystemClock_Config(void);

static void MX_GPIO_Init(void);

static void MX_CRC_Init(void);

static void MX_DMA2D_Init(void);

static void MX_FMC_Init(void);

static void MX_I2C3_Init(void);

static void MX_LTDC_Init(void);

static void MX_SPI5_Init(void);

static void MX_TIM1_Init(void);

static void MX_USART1_UART_Init(void);

void StartDefaultTask(void const * argument);

#define PUTCHAR_PROTOTYPE int __io_putchar(int ch)

PUTCHAR_PROTOTYPE

{

HAL_UART_Transmit(&huart, (uint8_t *)&ch, 1, 0xFFFF);

return ch;

}

int main(void)

{

/* USER CODE BEGIN 1 */

/* USER CODE END 1 */

/* MCU Configuration--------------------------------------------------------*/

/* Reset of all peripherals, Initializes the Flash interface and the Systick. */

HAL_Init();

/* USER CODE BEGIN Init */

/* USER CODE END Init */

/* Configure the system clock */

SystemClock_Config();

/* USER CODE BEGIN SysInit */

/* USER CODE END SysInit */

/* Initialize all configured peripherals */

MX_GPIO_Init();

MX_CRC_Init();

MX_DMA2D_Init();

MX_FMC_Init();

MX_I2C3_Init();

MX_LTDC_Init();

MX_SPI5_Init();

MX_TIM1_Init();

MX_USART1_UART_Init();

/* USER CODE BEGIN 2 */

/* USER CODE END 2 */

/* USER CODE BEGIN RTOS_MUTEX */

/* add mutexes, ... */

/* USER CODE END RTOS_MUTEX */

/* USER CODE BEGIN RTOS_SEMAPHORES */

/* add semaphores, ... */

/* USER CODE END RTOS_SEMAPHORES */

/* USER CODE BEGIN RTOS_TIMERS */

/* start timers, add new ones, ... */

/* USER CODE END RTOS_TIMERS */

/* USER CODE BEGIN RTOS_QUEUES */

/* add queues, ... */

/* USER CODE END RTOS_QUEUES */

/* Create the thread(s) */

/* definition and creation of defaultTask */

osThreadDef(defaultTask, StartDefaultTask, osPriorityNormal, 0, 4096);

defaultTaskHandle = osThreadCreate(osThread(defaultTask), NULL);

/* USER CODE BEGIN RTOS_THREADS */

/* add threads, ... */

/* USER CODE END RTOS_THREADS */

while (1)

{

printf("Hello World\n\r");

HAL_Delay(1000);

}

/* Start scheduler */

osKernelStart();

/* We should never get here as control is now taken by the scheduler */

/* Infinite loop */

/* USER CODE BEGIN WHILE */

while (1)

{

/* USER CODE END WHILE */

/* USER CODE BEGIN 3 */

}

/* USER CODE END 3 */

}