UART RX problem. TM4C123G.

Hello Gytis,

The issue is here. Since there are no characters it does not enter the while loop.

while(UARTCharsAvail(UART0_BASE))

Regards

Amit

Thank you for your answer Amit! I try this way, but still not working...

while(1) {

     while(UARTCharsAvail(UART0_BASE))
     {
        while(UARTCharGet(UART0_BASE)!=0x44) // 0x44 equal to D.
        {
        }

        readvalue = UARTCharGet(UART0_BASE);
        if(readvalue==0)
        {
        GPIOPinWrite(GPIO_PORTF_BASE, RED_LED|BLUE_LED|GREEN_LED, BLUE_LED);
        SysCtlDelay(1000000);
        GPIOPinWrite(GPIO_PORTF_BASE, RED_LED|BLUE_LED|GREEN_LED, 0x00);
        }
        else
        {
        GPIOPinWrite(GPIO_PORTF_BASE, RED_LED|BLUE_LED|GREEN_LED, RED_LED);
        SysCtlDelay(1000000);
        GPIOPinWrite(GPIO_PORTF_BASE, RED_LED|BLUE_LED|GREEN_LED, 0x00);
        }
    }
}
}

But if i write this way, microcontroller led turn on pressed every button even D (which is 0x44).. so it seems that  is not while loop problem.

while(1) {

     while(UARTCharsAvail(UART0_BASE))
     {
        while(UARTCharGet(UART0_BASE)!=0x44) // 0x44 equal to D.
        {
            GPIOPinWrite(GPIO_PORTF_BASE, RED_LED|BLUE_LED|GREEN_LED, BLUE_LED);
            SysCtlDelay(1000000);
            GPIOPinWrite(GPIO_PORTF_BASE, RED_LED|BLUE_LED|GREEN_LED, 0x00);
        }
    }
}

Hello Gytis,

UARTCharGet returns the 32-bit value of the DR register. This includes the Error Flag. It is possible one of the Error flags is being set. You would need to check which error flag in bits 11:8 is being set.

Regards

Amit

Yes, thank you! now it try with UART interrupt.

One more question.

#include <stdint.h>
#include <stdbool.h>
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "inc/tm4c123gh6pm.h"
#include "driverlib/debug.h"
#include "driverlib/sysctl.h"
#include "driverlib/gpio.h"
#include "driverlib/pin_map.h"
#include "inc/hw_gpio.h"
#include "driverlib/uart.h"
#include "utils/uartstdio.h"
#include "inc/hw_ints.h"
#include "driverlib/interrupt.h"

void UARTIntHandler(void)
{
    uint32_t ui32Status;
    ui32Status = UARTIntStatus(UART0_BASE, true); //get interrupt status
    UARTIntClear(UART0_BASE, ui32Status); //clear the asserted interrupts

    while(UARTCharsAvail(UART0_BASE)) //loop while there are chars
    {


        if(UARTCharGet(UART0_BASE)==0x44) // 0x44 equal to D.
        {
            GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_2, GPIO_PIN_2);
            SysCtlDelay(100000);
            GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_2, 0x00);
        }
    }

}
int main(void) {

    SysCtlClockSet(SYSCTL_SYSDIV_4 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_16MHZ);

    SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
    GPIOPinConfigure(GPIO_PA0_U0RX);
    GPIOPinConfigure(GPIO_PA1_U0TX);

    GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF); //enable GPIO port for LED
    GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_2); //enable pin for LED PF2

    UARTConfigSetExpClk(UART0_BASE, SysCtlClockGet(), 115200,
    (UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE | UART_CONFIG_PAR_NONE));

    UARTStdioConfig(0, 115200, 16000000);

    IntMasterEnable(); //enable processor interrupts
    IntEnable(INT_UART0); //enable the UART interrupt
    UARTIntEnable(UART0_BASE, UART_INT_RX | UART_INT_RT); //only enable RX and TX interrupts

    UARTprintf("Welcome to the Tiva C Series TM4C123G LaunchPad!\n");

    while (1)
    {
    }
}

uart interrupt work nice until I add these two marked lines..

writting error's:

">#10234-D</a>  unresolved symbols remain    lab12

#10010 errors encountered during linking; "lab12.out" not built    lab12     

unresolved symbol UARTStdioConfig, first referenced in ./main.obj    lab12             C/C++ Problem

unresolved symbol UARTprintf, first referenced in ./main.obj    lab12             C/C++ Problem

How I could solve these error's?

Hello Gytis

Please add the uartsdio.c to the project

Regards

Amit

#include <stdint.h>
#include <stdbool.h>
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/gpio.h"
#include "driverlib/pin_map.h"
#include "driverlib/sysctl.h"
#include "driverlib/uart.h"
#include "inc/hw_ints.h"
#include "driverlib/interrupt.h"
#include "utils/uartstdio.h"

 static char g_cInput[6];
 static char g_string[6] = "hello";

void UARTIntHandler(void)
{
    uint32_t ui32Status;
    ui32Status = UARTIntStatus(UART0_BASE, true); //get interrupt status
    UARTIntClear(UART0_BASE, ui32Status); //clear the asserted interrupts

        while(UARTPeek('\r') != -1)
        {
            UARTgets(g_cInput,sizeof(g_cInput));
        }

        if(g_cInput == g_string)
        {
            GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_2, GPIO_PIN_2); //blink LED
            SysCtlDelay(SysCtlClockGet() / (1000 * 3)); //delay ~1 msec
            GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_2, 0);
        }
}

int main(void) {

    SysCtlClockSet(SYSCTL_SYSDIV_4 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_16MHZ);

    SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);

    GPIOPinConfigure(GPIO_PA0_U0RX);
    GPIOPinConfigure(GPIO_PA1_U0TX);
    GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);

    UARTConfigSetExpClk(UART0_BASE, SysCtlClockGet(), 115200,
        (UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE | UART_CONFIG_PAR_NONE));

    IntMasterEnable();
    IntEnable(INT_UART0);
    UARTIntEnable(UART0_BASE, UART_INT_RX | UART_INT_RT);

    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);
    GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_2);


    UARTStdioConfig(0, 115200, 16000000);

    UARTprintf("Welcome to the Tiva C Series TM4C123G LaunchPad!\n");


    while (1)
    {
        //if (UARTCharsAvail(UART0_BASE)) UARTCharPut(UART0_BASE, UARTCharGet(UART0_BASE));
    }

}

Something with this code is wrong.. It's don't work currectly.. I writting word "hello" and enter button to microcontroller with putty program.

Gytis,

Were you sucessfull in running the second part of lab12 with the added interupt code?  I am having trouble gettting this to run.  It immediately goes to the interupt fault loop.  I would appreciate any ideas on how to determine what is causing this.

Chip

Hi Chip,

      Provide your code so others can review it, including startup file.

      Also it would be much better if you make a new post regarding your question.

-kel

Hello Gytis,

Please remove the second UART Coniguration UARTStdioConfig(0, 115200, 16000000); The code has already configured UART based on the System Clock Frequency and the second configuration is changing the Baud Rate incorrectly.

Regards,

Amit

Kel,

I added a new post with my code here: http://e2e.ti.com/support/microcontrollers/tiva_arm/f/908/t/331057.aspx

Thanks,

Chip