CD74HC4067.cpp

00001 //CD74HC4067 Library based on bildr code: "http://bildr.org/2011/02/cd74hc4067-arduino/"
00002 //Ported to mbed by Scott M. O'Hair
00003 
00004 #include "CD74HC4067.h"
00005 #include "mbed.h"
00006 
00007 
00008 CD74HC4067::CD74HC4067(PinName S1, PinName S2, PinName S3, PinName S4, PinName SIG) : _S0(S1), _S1(S2), _S2(S3), _S3(S4), _SIG(SIG)
00009 {
00010     //initialize port state to zero
00011     for (uint8_t i = 0; i < 15; i++) {
00012         portState[i] = 0.0;
00013     }
00014 
00015     //pull all pins low
00016     _S0 = 0;
00017     _S1 = 0;
00018     _S2 = 0;
00019     _S3 = 0;
00020 
00021 }
00022 
00023 void CD74HC4067::saveState(uint8_t port, float state)
00024 {
00025     this->portState[port] = state;
00026 }
00027 
00028 float CD74HC4067::readMux(uint8_t channel)
00029 {
00030     DigitalOut controlPin[] = {_S0, _S1, _S2, _S3};
00031 
00032     uint8_t muxChannel[16][4]= {
00033         {0,0,0,0}, //channel 0
00034         {1,0,0,0}, //channel 1
00035         {0,1,0,0}, //channel 2
00036         {1,1,0,0}, //channel 3
00037         {0,0,1,0}, //channel 4
00038         {1,0,1,0}, //channel 5
00039         {0,1,1,0}, //channel 6
00040         {1,1,1,0}, //channel 7
00041         {0,0,0,1}, //channel 8
00042         {1,0,0,1}, //channel 9
00043         {0,1,0,1}, //channel 10
00044         {1,1,0,1}, //channel 11
00045         {0,0,1,1}, //channel 12
00046         {1,0,1,1}, //channel 13
00047         {0,1,1,1}, //channel 14
00048         {1,1,1,1}  //channel 15
00049     };
00050 
00051     //loop through the 4 sig
00052     for(uint8_t i = 0; i < 4; i++) {
00053         controlPin[i] =  muxChannel[channel][i];
00054     }
00055 
00056     //read the value at the SIG pin
00057     float val = _SIG.read();
00058 
00059     //return the value
00060     return val;
00061 }