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:
2013-06-16
Revision:
2:bb19e60cb933
Parent:
1:fb35e688f9f4
Child:
4:07dd82e3f934

File content as of revision 2:bb19e60cb933:

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

DigitalOut blinker (LED_BLUE);
DigitalOut cmpled (LED_GREEN);
DigitalOut cmp_en (PTD5);
AnalogIn cmp_lvl (PTB0);
ComparatorIn compi(PTC8, PTE30); // in+ = PTC8, in- = 12-bit DAC 

// Comparator callback functions
void cmp_rise_ISR(void)
{
    cmpled = 0;
}

void cmp_fall_ISR(void)
{
    cmpled = 1;
}



int main()
{
    cmp_en = 1;
    cmpled = 1;

    compi.rising(&cmp_rise_ISR);                // Set pointer to rising interrupt function
    compi.falling(&cmp_fall_ISR);               // Set pointer to falling interrupt function
    compi.treshold(0.3);                        // Set comparator threshold to 1V = 0.3 * 3.3V
    compi.int_en(1);                            // Enable comparator interrupts

    while(1)
    {
        printf("Light sensor : %7.5f Volt\n",cmp_lvl*3.3);
        blinker = 1;
        wait(1);
        blinker = 0;
        wait(0.2);
        if (compi.status() == 0x01)
        {
            printf("*** Treshold reached : %7.5f\n",cmp_lvl*3.3);
        }
    }
}