Martin Cottrell / MicroBitPCA9685

microbit fork

Dependents:   demoMicroBit_PCA9685

Fork of PCA9685PWM by Paolo Sanna

PCA9685.cpp@0:c7f4744deec3, 2015-07-22 (annotated)

Committer:
dreamworker
Date:
Wed Jul 22 08:06:28 2015 +0000
Revision:
0:c7f4744deec3
Library for 16-channel, 12-bit PWM Fm+ I?C-bus LED controller PCA9685 of NXP.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
dreamworker 0:c7f4744deec3 1 #include "PCA9685.h"
dreamworker 0:c7f4744deec3 2 #include "mbed.h"
dreamworker 0:c7f4744deec3 3 PCA9685::PCA9685(PinName sda, PinName scl, int addr) : i2c(sda, scl), _i2caddr(addr) {}
dreamworker 0:c7f4744deec3 4
dreamworker 0:c7f4744deec3 5 void PCA9685::begin(void)
dreamworker 0:c7f4744deec3 6 {
dreamworker 0:c7f4744deec3 7 reset();
dreamworker 0:c7f4744deec3 8 }
dreamworker 0:c7f4744deec3 9
dreamworker 0:c7f4744deec3 10 void PCA9685::frequencyI2C(int freq)
dreamworker 0:c7f4744deec3 11 {
dreamworker 0:c7f4744deec3 12 i2c.frequency(freq);
dreamworker 0:c7f4744deec3 13 }
dreamworker 0:c7f4744deec3 14 void PCA9685::write8(uint8_t address, uint8_t data)
dreamworker 0:c7f4744deec3 15 {
dreamworker 0:c7f4744deec3 16 char cmd[2];
dreamworker 0:c7f4744deec3 17 cmd[0] = address;
dreamworker 0:c7f4744deec3 18 cmd[1] = data;
dreamworker 0:c7f4744deec3 19 i2c.write(_i2caddr, cmd, 2);
dreamworker 0:c7f4744deec3 20 }
dreamworker 0:c7f4744deec3 21
dreamworker 0:c7f4744deec3 22 char PCA9685::read8(char address)
dreamworker 0:c7f4744deec3 23 {
dreamworker 0:c7f4744deec3 24 i2c.write(_i2caddr, &address, 1);
dreamworker 0:c7f4744deec3 25 char rtn;
dreamworker 0:c7f4744deec3 26 i2c.read(_i2caddr, &rtn, 1);
dreamworker 0:c7f4744deec3 27 return rtn;
dreamworker 0:c7f4744deec3 28 }
dreamworker 0:c7f4744deec3 29
dreamworker 0:c7f4744deec3 30 void PCA9685::reset(void)
dreamworker 0:c7f4744deec3 31 {
dreamworker 0:c7f4744deec3 32 write8(PCA9685_MODE1, 0x0);
dreamworker 0:c7f4744deec3 33 }
dreamworker 0:c7f4744deec3 34 void PCA9685::setPrescale(uint8_t prescale) {
dreamworker 0:c7f4744deec3 35 uint8_t oldmode = read8(PCA9685_MODE1);
dreamworker 0:c7f4744deec3 36 uint8_t newmode = (oldmode&0x7F) | 0x10; // sleep
dreamworker 0:c7f4744deec3 37 write8(PCA9685_MODE1, newmode); // go to sleep
dreamworker 0:c7f4744deec3 38 wait_ms(5);
dreamworker 0:c7f4744deec3 39 write8(PCA9685_PRESCALE, prescale); // set the prescaler
dreamworker 0:c7f4744deec3 40 write8(PCA9685_MODE1, oldmode);
dreamworker 0:c7f4744deec3 41 wait_ms(5);
dreamworker 0:c7f4744deec3 42 write8(PCA9685_MODE1, oldmode | 0xa1);
dreamworker 0:c7f4744deec3 43 }
dreamworker 0:c7f4744deec3 44 void PCA9685::setPWMFreq(float freq)
dreamworker 0:c7f4744deec3 45 {
dreamworker 0:c7f4744deec3 46 float prescaleval = 25000000;
dreamworker 0:c7f4744deec3 47 prescaleval /= 4096;
dreamworker 0:c7f4744deec3 48 prescaleval /= freq;
dreamworker 0:c7f4744deec3 49 uint8_t prescale = floor(prescaleval + 0.5) - 1;
dreamworker 0:c7f4744deec3 50 setPrescale(prescale);
dreamworker 0:c7f4744deec3 51 }
dreamworker 0:c7f4744deec3 52
dreamworker 0:c7f4744deec3 53 void PCA9685::setPWM(uint8_t num, uint16_t on, uint16_t off)
dreamworker 0:c7f4744deec3 54 {
dreamworker 0:c7f4744deec3 55 char cmd[5];
dreamworker 0:c7f4744deec3 56 cmd[0] = LED0_ON_L + 4 * num;
dreamworker 0:c7f4744deec3 57 cmd[1] = on;
dreamworker 0:c7f4744deec3 58 cmd[2] = on >> 8;
dreamworker 0:c7f4744deec3 59 cmd[3] = off;
dreamworker 0:c7f4744deec3 60 cmd[4] = off >> 8;
dreamworker 0:c7f4744deec3 61 i2c.write(_i2caddr, cmd, 5);
dreamworker 0:c7f4744deec3 62 }