Library for 16-channel, 12-bit PWM controller NXP PCA9685.
Dependents: PCA9685_Hello_World PCA9685_with_LED PCA9685 AUTOBOT-LIBRARY
PCA9685.cpp@1:7f3c3ac6b20b, 2015-07-24 (annotated)
- Committer:
- dreamworker
- Date:
- Fri Jul 24 09:03:58 2015 +0000
- Revision:
- 1:7f3c3ac6b20b
- Parent:
- 0:c7f4744deec3
Pre-scale value corrected
Who changed what in which revision?
User | Revision | Line number | New 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 | } |