dengfeng li / Mbed 2 deprecated dac_subsystem

dac subsystem

Dependencies:   mbed MCP4725

DAC/DAC.cpp@1:8056d0c97ee2, 2014-04-01 (annotated)

Committer:
dzl5187
Date:
Tue Apr 01 04:47:27 2014 +0000
Revision:
1:8056d0c97ee2
Parent:
0:c7adfe979a5b 
first commit;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
dzl5187 0:c7adfe979a5b 1 #include "mbed.h"
dzl5187 0:c7adfe979a5b 2 #include "mcp4725.h"
dzl5187 0:c7adfe979a5b 3 #include "DAC.h"
dzl5187 0:c7adfe979a5b 4 #include "math.h"
dzl5187 0:c7adfe979a5b 5 #include "log.h"
dzl5187 0:c7adfe979a5b 6
dzl5187 0:c7adfe979a5b 7 #define PI 3.1415926
dzl5187 0:c7adfe979a5b 8 MCP4725 controller(p9, p10, MCP4725::Fast400kHz, DEVICE_ADDR_BIT);
dzl5187 0:c7adfe979a5b 9 Timer DAC_timer;
dzl5187 0:c7adfe979a5b 10
dzl5187 0:c7adfe979a5b 11 bool volatile DAC_running = false;
dzl5187 0:c7adfe979a5b 12 float p_range = 0;
dzl5187 0:c7adfe979a5b 13 enum FREQ p_freq = FREQ_10HZ;
dzl5187 0:c7adfe979a5b 14 enum FORM p_form = FORM_SQUARE;
dzl5187 0:c7adfe979a5b 15
dzl5187 0:c7adfe979a5b 16 void DAC_start(){
dzl5187 0:c7adfe979a5b 17 DAC_running = true;
dzl5187 0:c7adfe979a5b 18 }
dzl5187 0:c7adfe979a5b 19
dzl5187 0:c7adfe979a5b 20 void DAC_stop(){
dzl5187 0:c7adfe979a5b 21 DAC_running = false;
dzl5187 0:c7adfe979a5b 22 }
dzl5187 0:c7adfe979a5b 23 void DAC_set(float range, enum FREQ freq, enum FORM form){
dzl5187 0:c7adfe979a5b 24 p_range = range;
dzl5187 0:c7adfe979a5b 25 p_freq = freq;
dzl5187 0:c7adfe979a5b 26 p_form = form;
dzl5187 0:c7adfe979a5b 27 }
dzl5187 0:c7adfe979a5b 28
dzl5187 0:c7adfe979a5b 29 void DAC_generate(){
dzl5187 0:c7adfe979a5b 30 float Vout = 0;
dzl5187 0:c7adfe979a5b 31 int time_us = 0;
dzl5187 0:c7adfe979a5b 32 DAC_timer.start();
dzl5187 0:c7adfe979a5b 33 while( DAC_running ){
dzl5187 0:c7adfe979a5b 34 if( p_form == FORM_SQUARE ){
dzl5187 0:c7adfe979a5b 35 if( p_freq == FREQ_10HZ ){
dzl5187 0:c7adfe979a5b 36 //generate square wave at 10HZ
dzl5187 0:c7adfe979a5b 37 if( (int)time_us % 1000000 <= 500000){ // T = 100 ms
dzl5187 0:c7adfe979a5b 38 Vout = p_range;
dzl5187 0:c7adfe979a5b 39 }
dzl5187 0:c7adfe979a5b 40 else
dzl5187 0:c7adfe979a5b 41 Vout = 0;
dzl5187 0:c7adfe979a5b 42 }
dzl5187 0:c7adfe979a5b 43 else{
dzl5187 0:c7adfe979a5b 44 //generate square wave at 1HZ
dzl5187 0:c7adfe979a5b 45 if( (int)time_us % 1000000 <= 500000) //T = 1 s
dzl5187 0:c7adfe979a5b 46 Vout = p_range;
dzl5187 0:c7adfe979a5b 47 else
dzl5187 0:c7adfe979a5b 48 Vout = 0;
dzl5187 0:c7adfe979a5b 49 }
dzl5187 0:c7adfe979a5b 50 }
dzl5187 0:c7adfe979a5b 51 else if ( p_form == FORM_SIN){
dzl5187 0:c7adfe979a5b 52 if( p_freq == FREQ_10HZ ){
dzl5187 0:c7adfe979a5b 53 Vout = p_range / 2.0 * (sin( 2.0 * PI * 10.0 * time_us / 1000000.0) + 1);
dzl5187 0:c7adfe979a5b 54 }
dzl5187 0:c7adfe979a5b 55 else{
dzl5187 0:c7adfe979a5b 56 //generate sin wave at 1HZ
dzl5187 0:c7adfe979a5b 57 Vout = p_range / 2.0 * (sin( 2.0 * PI * 1.0 * time_us / 1000000.0) + 1);
dzl5187 0:c7adfe979a5b 58 }
dzl5187 0:c7adfe979a5b 59 }
dzl5187 0:c7adfe979a5b 60 wait_us(1000); //delay 1 ms
dzl5187 0:c7adfe979a5b 61 time_us += 1000;
dzl5187 0:c7adfe979a5b 62 controller.write(MCP4725::Normal, (0xFFF * (Vout/VDD_VOLTAGE) ), false);
dzl5187 0:c7adfe979a5b 63 }
dzl5187 0:c7adfe979a5b 64 DAC_timer.stop();
dzl5187 0:c7adfe979a5b 65 DAC_timer.reset();
dzl5187 0:c7adfe979a5b 66
dzl5187 0:c7adfe979a5b 67 }