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@2:bb19e60cb933, 2013-06-16 (annotated)

Committer:
frankvnk
Date:
Sun Jun 16 15:17:56 2013 +0000
Revision:
2:bb19e60cb933
Parent:
1:fb35e688f9f4
Child:
4:07dd82e3f934
added 12-bit DAC demo

Who changed what in which revision?

UserRevisionLine numberNew contents of line
frankvnk 2:bb19e60cb933 1 #include "ComparatorIn.h"
frankvnk 2:bb19e60cb933 2 #include "mbed.h"
frankvnk 2:bb19e60cb933 3
frankvnk 2:bb19e60cb933 4 DigitalOut blinker (LED_BLUE);
frankvnk 2:bb19e60cb933 5 DigitalOut cmpled (LED_GREEN);
frankvnk 2:bb19e60cb933 6 DigitalOut cmp_en (PTD5);
frankvnk 2:bb19e60cb933 7 AnalogIn cmp_lvl (PTB0);
frankvnk 2:bb19e60cb933 8 ComparatorIn compi(PTC8, PTE30); // in+ = PTC8, in- = 12-bit DAC
frankvnk 2:bb19e60cb933 9
frankvnk 2:bb19e60cb933 10 // Comparator callback functions
frankvnk 2:bb19e60cb933 11 void cmp_rise_ISR(void)
frankvnk 2:bb19e60cb933 12 {
frankvnk 2:bb19e60cb933 13 cmpled = 0;
frankvnk 2:bb19e60cb933 14 }
frankvnk 2:bb19e60cb933 15
frankvnk 2:bb19e60cb933 16 void cmp_fall_ISR(void)
frankvnk 2:bb19e60cb933 17 {
frankvnk 2:bb19e60cb933 18 cmpled = 1;
frankvnk 2:bb19e60cb933 19 }
frankvnk 2:bb19e60cb933 20
frankvnk 2:bb19e60cb933 21
frankvnk 2:bb19e60cb933 22
frankvnk 2:bb19e60cb933 23 int main()
frankvnk 2:bb19e60cb933 24 {
frankvnk 2:bb19e60cb933 25 cmp_en = 1;
frankvnk 2:bb19e60cb933 26 cmpled = 1;
frankvnk 2:bb19e60cb933 27
frankvnk 2:bb19e60cb933 28 compi.rising(&cmp_rise_ISR); // Set pointer to rising interrupt function
frankvnk 2:bb19e60cb933 29 compi.falling(&cmp_fall_ISR); // Set pointer to falling interrupt function
frankvnk 2:bb19e60cb933 30 compi.treshold(0.3); // Set comparator threshold to 1V = 0.3 * 3.3V
frankvnk 2:bb19e60cb933 31 compi.int_en(1); // Enable comparator interrupts
frankvnk 2:bb19e60cb933 32
frankvnk 2:bb19e60cb933 33 while(1)
frankvnk 2:bb19e60cb933 34 {
frankvnk 2:bb19e60cb933 35 printf("Light sensor : %7.5f Volt\n",cmp_lvl*3.3);
frankvnk 2:bb19e60cb933 36 blinker = 1;
frankvnk 2:bb19e60cb933 37 wait(1);
frankvnk 2:bb19e60cb933 38 blinker = 0;
frankvnk 2:bb19e60cb933 39 wait(0.2);
frankvnk 2:bb19e60cb933 40 if (compi.status() == 0x01)
frankvnk 2:bb19e60cb933 41 {
frankvnk 2:bb19e60cb933 42 printf("*** Treshold reached : %7.5f\n",cmp_lvl*3.3);
frankvnk 2:bb19e60cb933 43 }
frankvnk 2:bb19e60cb933 44 }
frankvnk 2:bb19e60cb933 45 }
frankvnk 2:bb19e60cb933 46
frankvnk 2:bb19e60cb933 47
frankvnk 2:bb19e60cb933 48