PCA9532.cpp

00001 /*
00002 PCA9532
00003 (c) 2009, cstyles
00004 */
00005 
00006 #include "PCA9532.h"
00007 #include "mbed.h"
00008 
00009 /*
00010  Constructor, pin names for I2C and the I2C addrss of the device
00011  */
00012 
00013 
00014 PCA9532::PCA9532(PinName scl, PinName sda, int addr) 
00015   : _i2c(scl, sda) {    
00016 
00017   _addr = addr;
00018   
00019 }
00020 
00021 
00022 
00023 
00024 
00025 /*
00026  force the LEDs on or off according to thier corresponding bits
00027  in the vector
00028  */
00029 
00030 void PCA9532::write (int leds) {
00031 
00032     // cycle through the array
00033     for (int i=0; i < 16; i++) {
00034 
00035         // if the ith bit is '1'
00036         if (leds & (0x1 << i)) {
00037             _rmw(i,PCA9532_MODE_SET);
00038         }
00039 
00040         else {
00041             _rmw(i,PCA9532_MODE_CLEAR);
00042         }    
00043     }
00044 }
00045 
00046 
00047 
00048 /*
00049  this is one hot encoding for the LED array
00050  any bit set will have it's corresponding LED switched on
00051  */
00052 
00053 void PCA9532::set (int leds) {
00054     for (int i=0; i < 16; i++) {
00055         if (leds & (0x1 << i)) {
00056             _rmw(i,PCA9532_MODE_SET);
00057         }
00058     }
00059 }
00060 
00061 
00062 void PCA9532::clear (int leds) {
00063     for (int i=0; i < 16; i++) {
00064         if (leds & (0x1 << i)) {
00065             _rmw(i,PCA9532_MODE_CLEAR);
00066         }
00067     }
00068 }
00069 
00070 
00071 void PCA9532::pwm0 (int leds) {
00072     for (int i=0; i < 16; i++) {
00073         if (leds & (0x1 << i)) {
00074             _rmw(i,PCA9532_MODE_PWM0);
00075         }
00076     }
00077 }
00078 
00079 
00080 void PCA9532::pwm1 (int leds) {
00081     for (int i=0; i < 16; i++) {
00082         if (leds & (0x1 << i)) {
00083             _rmw(i,PCA9532_MODE_PWM1);
00084         }
00085     }
00086 }
00087 
00088 
00089 void PCA9532::duty0 (float d) {
00090 
00091 char duty = 0;
00092 
00093 if (d > 1.0) { duty = 255; }
00094 else if ( d < 0.0 ) { duty = 0; }
00095 else { duty = 256 * d; }
00096 
00097 _write(PCA9532_REG_PWM0,duty);
00098    
00099 }
00100 
00101 
00102 void PCA9532::duty1 (float d) {
00103 
00104 char duty = 0;
00105 
00106 if (d > 1.0) { duty = 255; }
00107 else if ( d < 0.0 ) { duty = 0; }
00108 else { duty = 256 * d; }
00109 
00110 _write(PCA9532_REG_PWM1,duty);
00111    
00112 }
00113 
00114 
00115 
00116 
00117 
00118 
00119 
00120 /*
00121  led is in the range 0-15
00122  mode is inthe range 0-3
00123  */
00124 
00125 void PCA9532::_rmw(int led, int mode) {
00126 
00127    int reg = 0;
00128    int offset = (led % 4);
00129 
00130    // makesure mode is within bounds
00131    if ( (mode < 0) || (mode > 3) ) {
00132        return;
00133    }
00134 
00135 
00136     // determine which register this is, 
00137     if (led < 4) {
00138         reg = PCA9532_REG_LS0;}
00139 
00140     else if ( (led > 3) && (led < 8) ) {
00141         reg = PCA9532_REG_LS1;}
00142 
00143     else if ( (led > 7) && (led < 12) ) {
00144         reg = PCA9532_REG_LS2;}
00145 
00146     else if ( (led > 11) && (led < 16) ) {
00147         reg = PCA9532_REG_LS3;}
00148         
00149     else { return; }
00150 
00151     // read the current status of the register
00152     char regval = _read(reg);
00153     
00154     // clear the two bit slice at the calculated offset
00155     regval &= ~(0x3 << (2 * offset));
00156     
00157     // now OR in the mode, shifted by 2 8 offset
00158     regval |= (mode << (2 * offset));
00159     
00160     // write this back
00161     
00162     _write(reg,regval);
00163     
00164     return;
00165 }
00166 
00167 
00168 void PCA9532::_write(int reg, int data) {
00169     char args[2];
00170     args[0] = reg;
00171     args[1] = data;
00172     _i2c.write(_addr,args,2);
00173 }
00174 
00175 
00176 int PCA9532::_read(int reg) {
00177     char args[2];
00178     args[0] = reg;
00179     _i2c.write(_addr,args,2);
00180     return(args[1]);
00181 }
00182 
00183 
00184 
00185 
00186