topic Re: Read string from uart in Kinetis Microcontrollers

Read string from uart

kanimozhiraju — Mon, 22 May 2017 05:04:35 GMT

Hi @ kerry,
with uart receive interrupt i try to read string and compare the string with constant string and process further.But i sent data from app and i received .I am not getting the data when i sent once i have to send 3 times to receive the printf statement .i will attach my code now

/* * File: receiving data from app * Purpose: Main * */

#include "common.h"#include "isr.h"

char data[10]="MEASR_TEMP;char testdata[10];char rec[10];uint8 s_flag=0;uint8 i=0;

void UART1_isr(void){ if (UART1_S1&UART_S1_RDRF_MASK) { while(i<10) { testdata[i] = UART1_D; i++; } // printf("%c",testdata); } strncpy(rec,testdata,10); if((strncmp(rec,data,10)==0)) { uint8 s_flag=1; }}

void main (void){ printf("kiosk implementation\n"); UART1_C2 |= UART_C2_RIE_MASK ; // UART1_D=testdata; enable_irq(47); while(1) { if(s_flag==1) { printf("spo2"); printf("level:\n"); } } }

Re: Read string from uart

kerryzhou — Mon, 22 May 2017 06:10:44 GMT

Hello kanimozhi Raju,

Thank you for your cooperation.

Your code is wrong, you can't write the UART1_isr like that.

Actually, after you enable the receive interrupt, then when the mcu received one byte, it will enter in the UART1_isr one times, the next byte data will caused the next ISR, you can't use the while() in the ISR, you must exit the interrupt handler to wait the next the byte coming.

I have modified your code like this:

#include "common.h"#include "isr.h"

char data[10]="MEASR_TEMP;
char testdata[10];
char rec[10];
uint8 s_flag=0;
volatile uint8 i=0;

void UART1_isr(void)
{
if (UART1_S1&UART_S1_RDRF_MASK)
{
testdata[i++] = UART1_D;
}

}

void main (void)
{
    printf("kiosk implementation\n");
    UART1_C2 |= UART_C2_RIE_MASK ;
    // UART1_D=testdata;
    enable_irq(47);
    while(1)
    {
      if(i>=10)
      {
        strncpy(rec,testdata,10);
        printf("spo2");
        printf("level:\n");
        i=0;
        s_flag=1;
       }

    }
}

Wish it helps you!

Have a great day,
Kerry

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Re: Read string from uart

kanimozhiraju — Mon, 22 May 2017 07:50:49 GMT

kerryzhou‌

I have tried tat code.when i give data,uart isr is not at all getting activated.

Re: Read string from uart

kanimozhiraju — Mon, 22 May 2017 08:24:24 GMT

I have tried tat code.when i give data,uart isr is not at all getting activated.

Re: Read string from uart

kerryzhou — Mon, 22 May 2017 09:00:09 GMT

Hi kanimozhi Raju,

I just simply modify your code, give you the process method.

Did your own code can enter receive uart isr before?

Have a great day,
Kerry