printf to serial through a queue

[zamek42]

Posted on October 30, 2016 at 10:11

Hi All,

I would like to use a queue to send printf outputs to a serial port. When I try to send something into the queue, its freezes after 3rd character. Here is the queue init code:

static struct {
osMessageQId receive_queue;
osMessageQId transmit_queue;
}console;
void console_init(void) {
if (!console_stream)
return;
osMessageQDef(transmit_queue,CONSOLE_BUFFER_SIZE, sizeof(uint8_t));
console.transmit_queue = osMessageCreate(osMessageQ(transmit_queue), NULL);
osMessageQDef(receive_queue, CONSOLE_BUFFER_SIZE, sizeof(uint8_t));
console.receive_queue = osMessageCreate(osMessageQ(receive_queue), NULL);
}

here is the putchar code:

PUTCHAR_PROTOTYPE
{
osMessagePut(console.transmit_queue, ch, 100);
return ch;
}

and here is the serial task code:

void console_task_func(void) {
if (!console_stream)
return;
osEvent ev;
for(;;) {
ev = osMessageGet(console.transmit_queue, 100);
if (ev.status==osEventMessage)
HAL_UART_Transmit(console_stream, (uint8_t *)&ev.value, (uint16_t)1, 10U);
}
}

I there any specialities if I want to use it from printf? thx Zamek #queue #printf

[rchrdlyon1]

Posted on November 03, 2016 at 13:34

A couple of things:

You can capture the printf output by implementing ''int _write(int fd, char *ptr, int len)''. Use a mail queue instead of a message queue, it's more efficient. Some example code I use with the STM32F407. printf output is captured an transferred to a diagnostic task using a mail queue. The task transmits the output to a serial port. Not much code, but effective. I'm sure you can improve it. --------------------------------------------------------------------------------

/* maximum permissible length of the mail data */

#define DIAG_MAIL_SIZE 255 /* definition of diagnostic serial mail type */ struct DIAG_MAIL {     /* an array for holding the data (normally a string) */     char data[DIAG_MAIL_SIZE];     /* the length of the data (normally the length a string) */     uint8_t length; }; --------------------------------------------------------------------------------

void MX_FREERTOS_Init(void) {

  .....     /* USER CODE BEGIN RTOS_QUEUES */   /* DiagSend mail queue */   osMailQDef(DiagSend, 8, struct DIAG_MAIL);   DiagSendHandle = osMailCreate(osMailQ(DiagSend), NULL);   /* USER CODE END RTOS_QUEUES */     ......   } ---------------------------------------------------------------------------------

/* global function to redirect printf */

int _write(int fd, char *ptr, int len) {     int result = 0;     if ((fd == STDOUT_FILENO) && (ptr != NULL) && (len > 0))     {         struct DIAG_MAIL* ptr_mail = osMailAlloc(DiagSendHandle, 0);         if (ptr_mail != NULL)         {             /* if necessary truncate the data length */             if (len > DIAG_MAIL_SIZE)             {                 len = DIAG_MAIL_SIZE;             };             /* copy data into the mail message */             arm_copy_q7((q7_t*) ptr, (q7_t*) ptr_mail->data, len);             ptr_mail->length = len;             /* put the mail into the queue */             osMailPut(DiagSendHandle, ptr_mail);             /* return the actual number of bytes placed in mail queue */             result = len;         };     };     return result; } ------------------------------------------------------------------------------

/* diagnostic serial task function */

void DiagSerTask(void const* argument) {     /* task loop */     while (1)     {         /* wait for an incoming mail */         osEvent evt = osMailGet(DiagSendHandle, osWaitForever);         if (evt.status == osEventMail)         {             /* save pointer to mail */             struct DIAG_MAIL* ptr_mail = evt.value.p;             /* transmit over serial port */             HAL_UART_Transmit_IT(&huart2, (uint8_t*) ptr_mail->data,                     ptr_mail->length);             /* wait for notification of transmission completion */             ulTaskNotifyTake(pdTRUE, portMAX_DELAY);             /* free mail */             osMailFree(DiagSendHandle, ptr_mail);         };     }; } /* serial transmit callback */ void HAL_UART_TxCpltCallback(UART_HandleTypeDef *ptr_huart) {     if (ptr_huart->Instance == USART2)     {         BaseType_t xHigherPriorityTaskWoken = pdFALSE;         /* notify task that the serial transmission is completed */         vTaskNotifyGiveFromISR(DiagSerHandle, &xHigherPriorityTaskWoken);         /* ensure return to highest priority unblocked */         portYIELD_FROM_ISR(xHigherPriorityTaskWoken);     }; } --------------------------------------------------------------------------- stmcube was used to setup USART2. use google to find out more about the printf/_write functions, etc ...

[zamek42]

Posted on November 14, 2016 at 09:25 Hi Richard, Thx a lot, it seems to be good for me:)