uart-example

Hi Amit,
I have changed the settings to 115200bps. And COM5 port (specific port) is selected in hyperlink. And now

"Enter text:"  is not displayed.

whatever I typed in the keyboard displayed in hyperlink and led blinks at the time. But how can i know the text is transmitted and recieved through controller? and may i know the expected output format of the example?

Hello Mary

The uart_echo example sends back the same data. To be certain and to be able to modify the data, in the interrupt handler change the while loop to read the data and do a case conversion using subtraction of the difference of upper and lower case and then send the modified data back

Regards
Amit

Hi Amit,

The GPIO_DATA register have 0x00000010. Is any header files need to be changed.

Hi Amit,

Actually I need to measure frequency deviation of AC signal. For that initially I am working with pulse. Now I develop a code to check zero crossing of AC input. Here is my code.  I am giving input such that, the input goes to zero for every 0.02sec. And I am using TimerValueGet to get time period. But for every cycle the timer value varies (input fall to zero in 0.02 sec interval). Can you suggest what may be the error? Timer value mostly changes between 250000 to 310000. And one more thing, the value Time (Time=(TimeCount/320000);) mostly shows 0.0/1609.  Thank you so much for your help.

#include <stdbool.h>
#include <stdint.h>
#include "inc/hw_memmap.h"
#include "driverlib/adc.h"
#include "driverlib/gpio.h"
#include "driverlib/sysctl.h"
#include "driverlib/adc.h"
#include "inc/hw_types.h"
#include "driverlib/fpu.h"
#include "driverlib/debug.h"
#include "driverlib/timer.h"
#include "driverlib/uart.h"
#include "utils/uartstdio.h"

#define GPIO_PA0_U0RX           0x00000001
#define GPIO_PA1_U0TX           0x00000401

volatile unsigned long Old_Count;
volatile unsigned long New_Count=0;
int FallingEdges=0;
volatile unsigned long TimeCount;
float Ans;
float frequency;
float freq;
float Time;
float Time2,freq2,frequency2;
int Cycle=0;
int Time1,Temp1,Time3,freq1,Temp2,freq3,frequency1,Temp3,frequency3;

void
ConfigureUART(void)
{
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
    GPIOPinConfigure(GPIO_PA0_U0RX);
    GPIOPinConfigure(GPIO_PA1_U0TX);
    GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);
    UARTClockSourceSet(UART0_BASE, UART_CLOCK_PIOSC);
    UARTStdioConfig(0, 115200, 16000000);
}

main(void) {

    uint32_t pui32ADC0Value[0];

    SysCtlClockSet(SYSCTL_SYSDIV_10 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN| SYSCTL_XTAL_16MHZ);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_ADC0);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOE);
	SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0);
	SysCtlDelay(3);

	TimerDisable(TIMER0_BASE,TIMER_A);
	TimerConfigure(TIMER0_BASE, TIMER_CFG_PERIODIC_UP);
	TimerLoadSet(TIMER0_BASE, TIMER_A, 0x00FFFFFF);
	TimerEnable(TIMER0_BASE, TIMER_A);
    GPIOPinTypeADC(GPIO_PORTE_BASE, GPIO_PIN_5);

    ADCIntEnable(ADC0_BASE, 3);
    ADCSequenceDisable(ADC0_BASE, 3);
    ADCSequenceConfigure(ADC0_BASE, 3, ADC_TRIGGER_PROCESSOR, 0);
    ADCSequenceStepConfigure(ADC0_BASE, 3, 0,ADC_CTL_CH8 | ADC_CTL_IE | ADC_CTL_END);

    ConfigureUART();

    UARTprintf("\033[2JFrequency Measurement:-\n");
    ADCSequenceEnable(ADC0_BASE, 3);

    while (1) {
        ADCProcessorTrigger(ADC0_BASE, 3);
        while (!ADCIntStatus(ADC0_BASE, 3, false))
        {
        }

        ADCIntClear(ADC0_BASE, 3);
        ADCSequenceDataGet(ADC0_BASE, 3, pui32ADC0Value);
        Ans=(pui32ADC0Value[0]*3.3)/4095;
        UARTprintf("\npui32ADC0Value[0]:%d\n",pui32ADC0Value[0]);

        if (pui32ADC0Value[0]==0)
        {
        	Old_Count=New_Count;
        	New_Count=TimerValueGet(TIMER0_BASE, TIMER_A);
        	UARTprintf("\nCycles:%d\n",Cycle);
        	TimeCount=New_Count-Old_Count;
      	  Time=((float)TimeCount/320000);
      	  freq=1/Time;
      	  frequency=freq*50;
      	  //for float
      	  Time1=Time;
      	  Time2=Time*100000;
      	  Temp1=Time1*100000;
      	  Time3=Time2-Temp1;

      	freq1=freq;
      	freq2=freq*100000;
      	Temp2=freq1*100000;
      	freq3=freq2-Temp2;

      	frequency1=frequency;
      	frequency2=frequency*100000;
      	Temp3=frequency1*100000;
      	frequency3=frequency2-Temp3;

      	UARTprintf("\nAns:%d\n",Ans);
        UARTprintf("\nCycles:%d\n",Cycle);
      	UARTprintf("\nNew_Count:%d\n",New_Count);
      	UARTprintf("\nOld_Count:%d\n",Old_Count);
      	UARTprintf("\nTimeCount:%d\n",TimeCount);
      	UARTprintf("\nTime:%d\n",Time);
      	UARTprintf("\nTime:%d.%d\n",Time1,Time3);
      	UARTprintf("\nFrequency:%d.%d\n",freq1,freq3);
      	UARTprintf("\nFrequency:%d.%d\n",frequency1,frequency3);

        }

}
}

Hi Amit,

I tried that with "if (pui32ADC0Value<20)". Other values made more deviate in the measurement. And I got the measured frequency values for absolute 50Hz frequency input in terminal are:

Freq:49.45384
Freq:49.45109
Freq:41.91323
Freq:49.46454
Freq:49.24365
Freq:49.1525
Freq:49.23228
Freq:49.1795
Freq:49.23137
Freq:41.89633
Freq:49.1690
Freq:49.23683
Freq:49.1555
Freq:49.23804
Freq:49.924
Freq:49.45843
Freq:49.789
Freq:41.90565
Freq:49.1570

And I can't get the correct frequency. Why the timer value that much varies? What I need to change in the code to get the correct measure?