CCS/CC2640: UART readtimeout does not work properly

Tuan Vu Phan

Part Number: CC2640

Tool/software: Code Composer Studio

i have a simple code to read from Uart on CC2640 MCU sdk 2.20.00.49

in Main.c

UART_init();

 uartParams.readTimeout=100*1000 / Clock_tickPeriod;

UART_Params_init(&uartParams);

 uart_handle= UART_open( Board_UART0, &uartParams );

in task thread (the thread created by main.c)

uint8_t rxbuf;
int count_rx=0,read=0;
while(1)
{
read=UART_read(uart_handle,&rxbuf,1);
Log_info0("\r\n buffer ch");
while(read)
{
Log_info3("\r\n buffer ch is %c and %d and %d ",rxbuf,count_rx,read);
dbgUartRxBuf[count_rx]=rxbuf;
count_rx++;
read=UART_read(uart_handle,&rxbuf,1);
}
count_rx=0;
//do next tasks

I do expect that if there is no new coming in uart buffer after 100ms, program will escape from while(read) and do next task with data and I used terminal on PC to test and when sending "START" to MCU and I got

[32;1mINFO: [30;1m(system_task.c:350) [0m
buffer ch is S and 0 and 1

[32;1mINFO: [30;1m(system_task.c:350) [0m
buffer ch is T and 1 and 1
[32;1mINFO: [30;1m(system_task.c:350) [0m
buffer ch is A and 2 and 1
[32;1mINFO: [30;1m(system_task.c:350) [0m
buffer ch is R and 3 and 1
[32;1mINFO: [30;1m(system_task.c:350) [0m
buffer ch is T and 4 and 1

then I waited a moment (minute) and sent a "q" , I got

q[32;1mINFO: [30;1m(system_task.c:350) [0m
buffer ch is q and 5 and 1

it means that loop while (read) still not is escaped and also the uart_read did not return (if return, it should print a lot of "buffer ch is") while the readtimeout is set to a specific value, not forever.

what is my mistake?

over 7 years ago

0 IUsedToBeARealPerson (M-W) over 7 years ago

TI__Guru 58425 points

Hi Tuan,

Could you fill in on which SDK version you are using as there has been many updates to the UART driver over time?

0 Tuan Vu Phan over 7 years ago in reply to IUsedToBeARealPerson (M-W)

Prodigy 190 points

Thank m-w for reminder. I updated

0 IUsedToBeARealPerson (M-W) over 7 years ago in reply to Tuan Vu Phan

TI__Guru 58425 points

I tried this out myself on the same SDK running the following code:

    char        input = 'A';
    const char  echoPrompt[] = "Echoing characters:\r\n";
    UART_Handle uart;
    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.readTimeout=100*1000 / 10;

    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);
    }

The read times out as expected. I suggest you try out the simple test I performed and see if you can get that to work.

0 Tuan Vu Phan over 7 years ago in reply to IUsedToBeARealPerson (M-W)

Prodigy 190 points

Even though I cannot find out what wrong in my code, at least the example works as you said. thanks

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CCS/CC2640: UART readtimeout does not work properly