PCA9685.cpp

00001 #include "PCA9685.h"
00002 #include "mbed.h"
00003 PCA9685::PCA9685(PinName sda, PinName scl, int addr) : i2c(sda, scl), _i2caddr(addr) {}
00004 
00005 void PCA9685::begin(void)
00006 {
00007     reset();
00008 }
00009 
00010 void PCA9685::frequencyI2C(int freq)
00011 {
00012     i2c.frequency(freq);
00013 }
00014 void PCA9685::write8(uint8_t address, uint8_t data)
00015 {
00016     char cmd[2];
00017     cmd[0] = address;
00018     cmd[1] = data;
00019     i2c.write(_i2caddr, cmd, 2);
00020 }
00021 
00022 char PCA9685::read8(char address)
00023 {
00024     i2c.write(_i2caddr, &address, 1);
00025     char rtn;
00026     i2c.read(_i2caddr, &rtn, 1);
00027     return rtn;
00028 }
00029 
00030 void PCA9685::reset(void)
00031 {
00032     write8(PCA9685_MODE1, 0x0);
00033 }
00034 void PCA9685::setPrescale(uint8_t prescale) {
00035     uint8_t oldmode = read8(PCA9685_MODE1);
00036     uint8_t newmode = (oldmode&0x7F) | 0x10; // sleep
00037     write8(PCA9685_MODE1, newmode); // go to sleep
00038     wait_ms(5);
00039     write8(PCA9685_PRESCALE, prescale); // set the prescaler
00040     write8(PCA9685_MODE1, oldmode);
00041     wait_ms(5);
00042     write8(PCA9685_MODE1, oldmode | 0xa1);
00043 }
00044 void PCA9685::setPWMFreq(float freq)
00045 {
00046     float prescaleval = 25000000;
00047     prescaleval /= 4096;
00048     prescaleval /= freq;
00049     uint8_t prescale = floor(prescaleval  + 0.5) - 1;
00050     setPrescale(prescale);
00051 }
00052 
00053 void PCA9685::setPWM(uint8_t num, uint16_t on, uint16_t off)
00054 {
00055     char cmd[5];
00056     cmd[0] = LED0_ON_L + 4 * num;
00057     cmd[1] = on;
00058     cmd[2] = on >> 8;
00059     cmd[3] = off;
00060     cmd[4] = off >> 8;
00061     i2c.write(_i2caddr, cmd, 5);
00062 }