Adafruit_PWMServoDriver.cpp

00001 /*************************************************** 
00002   This is a library for our Adafruit 16-channel PWM & Servo driver
00003 
00004   Pick one up today in the adafruit shop!
00005   ------> http://www.adafruit.com/products/815
00006 
00007   These displays use I2C to communicate, 2 pins are required to  
00008   interface. For Arduino UNOs, thats SCL -> Analog 5, SDA -> Analog 4
00009 
00010   Adafruit invests time and resources providing this open source code, 
00011   please support Adafruit and open-source hardware by purchasing 
00012   products from Adafruit!
00013 
00014   Written by Limor Fried/Ladyada for Adafruit Industries.  
00015   BSD license, all text above must be included in any redistribution
00016   
00017   Ported to mbed by Brian Dickman, mbed.org user bxd.
00018  ****************************************************/
00019 
00020 #include <Adafruit_PWMServoDriver.h>
00021 
00022 Adafruit_PWMServoDriver::Adafruit_PWMServoDriver(I2C *i2c, uint8_t addr) {
00023   _i2c = i2c;
00024  
00025   // Arduino WIRE library takes address as 7-bit (unshifted), mbed takes 8 bit.
00026   // in other words, use the Adafruit library default value 0x40 to talk with the breakout
00027   // if you use the default resistor config.
00028   _i2caddr = addr << 1;
00029 }
00030 
00031 void Adafruit_PWMServoDriver::begin(void) {
00032  reset();
00033 }
00034 
00035 
00036 void Adafruit_PWMServoDriver::reset(void) {
00037  
00038  // leave the ALL CALL address enabled (we might use that!)
00039  // if you don't want ALL CALL, write 00 to offset 00
00040  write8(PCA9685_MODE1, 0x1);
00041 }
00042 
00043 void Adafruit_PWMServoDriver::setPWMFreq(float freq) {
00044   //Serial.print("Attempting to set freq ");
00045   //Serial.println(freq);
00046   
00047   float prescaleval = 25000000;
00048   prescaleval /= 4096;
00049   prescaleval /= freq;
00050   prescaleval -= 1;
00051   //printf("Estimated pre-scale: %f\r\n", prescaleval);
00052   uint8_t prescale = floor(prescaleval + 0.5);
00053   //printf("Final pre-scale: %f", prescale);  
00054   
00055   uint8_t oldmode = read8(PCA9685_MODE1);
00056   uint8_t newmode = (oldmode&0x7F) | 0x10; // sleep
00057   write8(PCA9685_MODE1, newmode); // go to sleep
00058   write8(PCA9685_PRESCALE, prescale); // set the prescaler
00059   write8(PCA9685_MODE1, oldmode);
00060   //wait_ms(5);
00061   write8(PCA9685_MODE1, oldmode | 0xa1);  //  This sets the MODE1 register to turn on auto increment.
00062                                           // This is why the beginTransmission below was not working.
00063   //  Serial.print("Mode now 0x"); Serial.println(read8(PCA9685_MODE1), HEX);
00064 }
00065 
00066 void Adafruit_PWMServoDriver::setPWM(uint8_t num, uint16_t on, uint16_t off) {
00067   //Serial.print("Setting PWM "); Serial.print(num); Serial.print(": "); Serial.print(on); Serial.print("->"); Serial.println(off);
00068 
00069   int data[] = { LED0_ON_L+4*num, on, on >> 8, off, off >> 8 };
00070   _i2c->write(_i2caddr, (const char *)data, 5);
00071   /*
00072   WIRE.beginTransmission(_i2caddr);
00073   WIRE.write(LED0_ON_L+4*num);
00074   WIRE.write(on);
00075   WIRE.write(on>>8);
00076   WIRE.write(off);
00077   WIRE.write(off>>8);
00078   WIRE.endTransmission();
00079   */
00080 }
00081 
00082 uint8_t Adafruit_PWMServoDriver::read8(uint8_t addr) {
00083     char data;
00084     if(_i2c->write(_i2caddr, (char *)&addr, 1, true))
00085         printf("I2C ERR: no ack on write before read.\n");
00086     if(_i2c->read(_i2caddr, &data, 1))
00087         printf("I2C ERR: no ack on read\n");
00088     return (uint8_t)data;
00089 }
00090 
00091 void Adafruit_PWMServoDriver::write8(uint8_t addr, uint8_t d) {
00092     char data[] = { addr, d };
00093     if(_i2c->write(_i2caddr, data, 2))
00094     {    
00095         printf("I2C ERR: No ACK on i2c write!");
00096     }
00097 }