RTOS/CC3220: How to read UART in UART_MODE_CALLBACK ?

Raghunandana DS

Part Number: CC3220

Tool/software: TI-RTOS

Hi, I am trying access the UART read in UART_MODE_CALLBACK. Please find below code,

UART_Params uartParams;

    UART_init();
    UART_Params_init(&uartParams);
    uartParams.writeDataMode = UART_DATA_BINARY;
    uartParams.readDataMode = UART_DATA_BINARY;
    uartParams.readReturnMode = UART_RETURN_NEWLINE;//UART_RETURN_FULL;
    uartParams.readEcho = UART_ECHO_OFF;
    uartParams.readTimeout = UART_WAIT_FOREVER;
    uartParams.baudRate = 115200;
    uartParams.readCallback = &uart0ReadCallback;
    uartParams.readMode = UART_MODE_CALLBACK; //UART_MODE_BLOCKING for peripheral's

    uartHandle = UART_open(Board_UART0, &uartParams);

void uart0ReadCallback(UART_Handle handle, void *rxBuf, size_t size)
{
        UART_write(uartHandle, rxBuf, size);

}

The calback is not calling at any time. I tried for different modes like

UART_RETURN_FULL and UART_RETURN_NEWLINE

UART_MODE_CALLBACK and UART_MODE_BLOCKING

But the same will call the callback when I do like below

    UART_Params uartParams;

    UART_init();
    UART_Params_init(&uartParams);
    uartParams.writeDataMode = UART_DATA_BINARY;
    uartParams.readDataMode = UART_DATA_BINARY;
    uartParams.readReturnMode = UART_RETURN_NEWLINE;//UART_RETURN_FULL;
    uartParams.readEcho = UART_ECHO_OFF;
    uartParams.readTimeout = UART_WAIT_FOREVER;
    uartParams.baudRate = 115200;
    uartParams.readCallback = &uart0ReadCallback;
    uartParams.readMode = UART_MODE_CALLBACK; //UART_MODE_BLOCKING for peripheral's

    uartHandle = UART_open(Board_UART0, &uartParams);

    char input;
    while (1) {
          UART_read(uartHandle, &input, 1);
        }
}

So, the data is Receiving, why not in call back. Many threads regarding similar issues are not resolved my issues.

Thanks

Raghu

over 5 years ago

0 Vincent Rodriguez over 5 years ago

TI__Mastermind 28285 points

Raghu,

Please try calling UART_Read once, then waiting for the callback, so you aren't constantly calling UART_Read.

BR,
VInce

0 Raghunandana DS over 5 years ago in reply to Vincent Rodriguez

Mastermind 6385 points

Hi Vince,

I tried calling,

char input;

UART_read(uartHandle, &input, 128);

in the main thread after the successful init of UART0, no callback coming to "uart0ReadCallback"

Tried like below also

UART_Handle InitTerm(void)
{
    UART_Params uartParams;

    UART_init();
    UART_Params_init(&uartParams);
    uartParams.writeDataMode = UART_DATA_BINARY;
    uartParams.readDataMode = UART_DATA_BINARY;
    uartParams.readReturnMode = UART_RETURN_NEWLINE;//UART_RETURN_FULL;
    uartParams.readEcho = UART_ECHO_OFF;
    uartParams.readTimeout = UART_WAIT_FOREVER;
    uartParams.baudRate = 115200;
    uartParams.readCallback = &uart0ReadCallback;
    uartParams.readMode = UART_MODE_CALLBACK; //UART_MODE_BLOCKING for peripheral's

    uartHandle = UART_open(Board_UART0, &uartParams);

    char input;
          UART_read(uartHandle, &input, 128);//tried for size 1 also
}

void uart0ReadCallback(UART_Handle handle, void *rxBuf, size_t size)
{
        UART_write(uartHandle, rxBuf, size);
}

But no use

0 Vincent Rodriguez over 5 years ago in reply to Raghunandana DS

TI__Mastermind 28285 points

Looks like your issue is with the UART_RETURN_NEWLINE. What this means, is that the Callback or Blocking read will return only when it gets a new line character. What you want is UART_RETURN_FULL. This will return when the buffer is full. If you then use 1 as the buffer, any character you type will return in the call back. I would suggest looking at the UARTEcho example in the SDK for more info. Here is what i did to test.

/*
 * Copyright (c) 2015-2017, Texas Instruments Incorporated
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * *  Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * *  Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * *  Neither the name of Texas Instruments Incorporated nor the names of
 *    its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 *  ======== uartecho.c ========
 */
#include <stdint.h>
#include <stddef.h>

/* Driver Header files */
#include <ti/drivers/GPIO.h>
#include <ti/drivers/UART.h>

/* Example/Board Header files */
#include "Board.h"

UART_Handle uart;


void uart0ReadCallback(UART_Handle handle, void *rxBuf, size_t size)
{
    UART_write(uart, "\n\r", sizeof("\n\r"));
    UART_write(uart, rxBuf, size);
}
/*
 *  ======== mainThread ========
 */
void *mainThread(void *arg0)
{
    char        input;
    const char  echoPrompt[] = "Echoing characters:\r\n";
    UART_Params uartParams;

    /* Call driver init functions */
    GPIO_init();
    UART_init();

    /* Configure the LED pin */
    GPIO_setConfig(Board_GPIO_LED0, GPIO_CFG_OUT_STD | GPIO_CFG_OUT_LOW);

    /* Turn on user LED */
    GPIO_write(Board_GPIO_LED0, Board_GPIO_LED_ON);

    /* Create a UART with data processing off. */
    UART_Params_init(&uartParams);
    uartParams.writeDataMode = UART_DATA_BINARY;
    uartParams.readDataMode = UART_DATA_BINARY;
    uartParams.readReturnMode = UART_RETURN_FULL;
    uartParams.readEcho = UART_ECHO_OFF;
    uartParams.baudRate = 115200;
    uartParams.readCallback = &uart0ReadCallback;
    uartParams.readMode = UART_MODE_CALLBACK; //UART_MODE_BLOCKING for peripheral's

    uart = UART_open(Board_UART0, &uartParams);

    if (uart == NULL) {
        /* UART_open() failed */
        while (1);
    }

    UART_write(uart, echoPrompt, sizeof(echoPrompt));

    /* Loop forever echoing */
    while (1) {
        UART_read(uart, &input, 1);
       // UART_write(uart, &input, 1);
    }
}

0 Raghunandana DS over 5 years ago in reply to Vincent Rodriguez

Mastermind 6385 points

Hi Vince,
I tried as above, in your way SW is always looping to read UART0.
But I have other tasks to do after this, more I want UART1 also to enable. I don't think this solution will help. I want this to run on TI-RTOS project which is running 5 application tasks.
Thank you.

0 Vincent Rodriguez over 5 years ago in reply to Raghunandana DS

TI__Mastermind 28285 points

Place a semaphore pend after the read if it's not blocking, and post when you get into the interrupt handler. That way other tasks can run.

0 Raghunandana DS over 5 years ago in reply to Vincent Rodriguez

Mastermind 6385 points

Hi Vincent,

After Semaphore pend and Semaphore post cal, Now I am receiving Data which is coming to particular UART.

But after a while the receiving is stopped, but transmitting is happening(tested by prints for button press).

I mean after few characters received callback and Semaphore_pend are not calling (tested with break points on debug mode)

Please have look at my code:

 UART_Params uartParams;
UInt32 sleepTickCount;

Task_Struct task1Struct;
Char task1Stack[TASKSTACKSIZE];
Semaphore_Struct semStruct;
Semaphore_Handle semHandle;
UART_Handle uartHandle;

    /* Call driver init functions */
    UART_init();

    /* Create a UART with data processing off. */
    UART_Params_init(&uartParams);
    uartParams.writeDataMode = UART_DATA_BINARY;
    uartParams.readDataMode = UART_DATA_BINARY;
    uartParams.readReturnMode = UART_RETURN_NEWLINE;
    uartParams.readEcho = UART_ECHO_OFF;
    uartParams.baudRate = 115200;
    uartParams.readCallback = &uart0ReadCallback;
    uartParams.readMode = UART_MODE_CALLBACK;//UART_MODE_CALLBACK; //UART_MODE_BLOCKING for peripheral's

    uartHandle = UART_open(Board_UART0, &uartParams);

    if (uartHandle == NULL) {
        /* UART_open() failed */
        while (1);
    }

    /* Construct BIOS objects */
       Task_Params taskParams;
       Semaphore_Params semParams;

       /* Construct writer/reader Task threads */
       Task_Params_init(&taskParams);
       taskParams.stackSize = TASKSTACKSIZE;
       taskParams.stack = &task1Stack;
       taskParams.priority = 1;
       Task_construct(&task1Struct, (Task_FuncPtr)task1Fxn, &taskParams, NULL);

       /* Construct a Semaphore object to be use as a resource lock, inital count 1 */
       Semaphore_Params_init(&semParams);
       Semaphore_construct(&semStruct, 1, &semParams);

       /* Obtain instance handle */
       semHandle = Semaphore_handle(&semStruct);
       /* We want to sleep for 1000 microseconds */
       sleepTickCount = 1000 / Clock_tickPeriod;
.
.
.
.
.
.
.
.
.
.
void uart0ReadCallback(UART_Handle handle, void *rxBuf, size_t size)
{
    UART_write(uartHandle, rxBuf, size);
    Semaphore_post(semHandle);
}


Void task1Fxn(UArg arg0, UArg arg1)
{
    char        input;

    for (;;) {

        UART_read(uartHandle, &input, 1);

            /* Get access to resource */
        Semaphore_pend(semHandle, BIOS_WAIT_FOREVER);

        Task_sleep(sleepTickCount);
    }
}

Tried for different baud rates.

Thank you

0 Vincent Rodriguez over 5 years ago in reply to Raghunandana DS

TI__Mastermind 28285 points

Try removing the UART_Write from the callback and place it after the semaphore pend in your task1fxn.

Best Regards,
Vince

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RTOS/CC3220: How to read UART in UART_MODE_CALLBACK ?