Istvan Cserny / Mbed 2 deprecated 05_comparator_demo

Simple program to demonstrate the basic functions of the analog comparator of the FRDM-KL25Z board.

Dependencies:   ComparatorIn mbed

Fork of ComparatorIn_demo by Frank Vannieuwkerke

ComparatorIn demo

Simple program to demonstrate the basic functions of the analog comparator of the FRDM-KL25Z board.

The blue LED flashes after 2 sec delay. The green LED is driven by the interrupts of the Analog Comparator (LED ON at rising edge, LED OFF at falling edge).

The output of the Analog Comparatir is also tested by polling, the result is printed out at the standard output (UART0). The default speed and format (9600 bps, 8,N,1) are used.

Credits

This program is based on the ComparatorIn library and the ComparatorIn_demo program written by Frank Vannieuwkerke

Used library:

Hardware requirements:

  • FRDM-KL25 board
  • CdS photoresistor pulled up by 10 k

/media/uploads/icserny/05_comparator_demo.png

main.cpp

Committer:
frankvnk
Date:
2013-06-05
Revision:
0:e5deffde916d
Child:
1:fb35e688f9f4

File content as of revision 0:e5deffde916d:

#include "ComparatorIn.h"
#include "mbed.h"

DigitalOut myled(LED1); // Blue
DigitalOut cmpled(LED2); // Green
DigitalOut cmp_en (PTD5);
AnalogIn cmp_lvl (PTB0);
ComparatorIn compi(PTC8, NC); // light sensor comparator input

// Comparator callback function
void cmp_ISR(unsigned int cmp_ret)
{
    printf("\n%02X - Light sensor : %7.5f Volt - ",cmp_ret,cmp_lvl*3.3);
    if ((cmp_ret & CMP_SCR_CFR_MASK)==CMP_SCR_CFR_MASK)
    {
        printf("<INT=Rising edge on HSCMP0>\n");
    }
    if ((cmp_ret & CMP_SCR_CFF_MASK)==CMP_SCR_CFF_MASK)
    {
        printf("<INT=Falling edge on HSCMP0>\n ");
    }
}



int main()
{
    cmp_en = 1;

    compi._callbackISR(&cmp_ISR);               // Set comparator callback to cmp_ISR
    compi.treshold(0x20);                       // Set copmarator threshold to 1.03V = 20 * 3.3V / 64

    while(1)
    {
//        printf("InP : %02X - InM : %02X - DACCR : %02X\n",(CMP0->MUXCR & 0x38)>>3,(CMP0->MUXCR & 0x07),(CMP0->DACCR & 0x3f));
        printf("Light sensor : %7.5f Volt\n",cmp_lvl*3.3);
        myled = 1;
        wait(1);
        myled = 0;
        wait(0.2);
        if (compi.status() == 0x01)
        {
            cmpled = 0;
        }
        else
        {
            cmpled = 1;
        }
    }
}