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@8:a5b18dfe684f, 2015-11-18 (annotated)

Committer:
icserny
Date:
Wed Nov 18 15:29:18 2015 +0000
Revision:
8:a5b18dfe684f
Parent:
7:a4f884972a0e 
First version

Who changed what in which revision?

UserRevisionLine numberNew contents of line
icserny 8:a5b18dfe684f 1 /** 05_comparator_demo
icserny 7:a4f884972a0e 2 * Simple program to demonstrate the basic functions
icserny 7:a4f884972a0e 3 * of the analog comparator of the FRDM-KL25Z board.
icserny 7:a4f884972a0e 4 *
icserny 7:a4f884972a0e 5 * Used library:
icserny 7:a4f884972a0e 6 * - ComparatorIn //https://developer.mbed.org/users/frankvnk/code/ComparatorIn/
icserny 7:a4f884972a0e 7 * written by Frank Vannieuwkerke
icserny 7:a4f884972a0e 8 *
icserny 7:a4f884972a0e 9 * Hardware requirements:
icserny 7:a4f884972a0e 10 * - FRDM-KL25 board
icserny 7:a4f884972a0e 11 * - CdS photoresistor pulled up by 10 k
icserny 7:a4f884972a0e 12 * - Connecect the midpoint of the divider to PTE29
icserny 7:a4f884972a0e 13 *
icserny 7:a4f884972a0e 14 * 10k CdS photoresistor
icserny 7:a4f884972a0e 15 * +3.3V --/\/\/\---+---/\/\/\---- GND
icserny 7:a4f884972a0e 16 * |
icserny 7:a4f884972a0e 17 * PTE29
icserny 7:a4f884972a0e 18 *
icserny 7:a4f884972a0e 19 */
frankvnk 2:bb19e60cb933 20
icserny 7:a4f884972a0e 21 #include "mbed.h"
icserny 7:a4f884972a0e 22 #include "ComparatorIn.h"
icserny 7:a4f884972a0e 23
icserny 7:a4f884972a0e 24 DigitalOut blinker (LED_BLUE); // blinking LED
icserny 7:a4f884972a0e 25 DigitalOut cmpled (LED_GREEN); // signing comparator status
icserny 7:a4f884972a0e 26 AnalogIn cmp_lvl (PTE29); // ADC input to check comparator input
icserny 7:a4f884972a0e 27 ComparatorIn compi(PTE29, PTE30); // in+ = PTE29, in- = 12-bit DAC
icserny 7:a4f884972a0e 28
icserny 7:a4f884972a0e 29 // Comparator interrupt callback functions
frankvnk 2:bb19e60cb933 30 void cmp_rise_ISR(void)
frankvnk 2:bb19e60cb933 31 {
icserny 7:a4f884972a0e 32 cmpled = 0; // LED ON at rising edge
frankvnk 2:bb19e60cb933 33 }
icserny 7:a4f884972a0e 34
frankvnk 2:bb19e60cb933 35 void cmp_fall_ISR(void)
frankvnk 2:bb19e60cb933 36 {
icserny 7:a4f884972a0e 37 cmpled = 1; // LED OFF at falling edge
frankvnk 2:bb19e60cb933 38 }
icserny 7:a4f884972a0e 39
icserny 7:a4f884972a0e 40
icserny 7:a4f884972a0e 41
frankvnk 2:bb19e60cb933 42 int main()
frankvnk 2:bb19e60cb933 43 {
icserny 7:a4f884972a0e 44 cmpled = 1; // LED OFF at the beginning
icserny 7:a4f884972a0e 45
icserny 7:a4f884972a0e 46 compi.rising(&cmp_rise_ISR); // Set pointer to rising interrupt function
icserny 7:a4f884972a0e 47 compi.falling(&cmp_fall_ISR); // Set pointer to falling interrupt function
icserny 7:a4f884972a0e 48 compi.treshold(0.3); // Set comparator threshold to 1V = 0.3 * 3.3V
icserny 7:a4f884972a0e 49
frankvnk 2:bb19e60cb933 50 while(1)
frankvnk 2:bb19e60cb933 51 {
frankvnk 2:bb19e60cb933 52 printf("Light sensor : %7.5f Volt\n",cmp_lvl*3.3);
icserny 7:a4f884972a0e 53 blinker = 1; // binking LED OFF
icserny 7:a4f884972a0e 54 wait(2); // wait for 2 sec
icserny 7:a4f884972a0e 55 blinker = 0; // blinking LED ON
frankvnk 2:bb19e60cb933 56 wait(0.2);
icserny 7:a4f884972a0e 57 if (compi.status() == 0x01) // poll comparator status
frankvnk 2:bb19e60cb933 58 {
frankvnk 2:bb19e60cb933 59 printf("*** Treshold reached : %7.5f\n",cmp_lvl*3.3);
frankvnk 2:bb19e60cb933 60 }
frankvnk 2:bb19e60cb933 61 }
frankvnk 2:bb19e60cb933 62 }
icserny 7:a4f884972a0e 63
icserny 7:a4f884972a0e 64