带Atmega168的I2C

我正在尝试使用adafruit PWM伺服控制器控制几个伺服。它使用i2c接口与微控制器通信。 https://www.adafruit.com/product/815

#include "i2c.h"

void initI2C(void) {
  TWBR = 32;                               /* set bit rate, see p. 242 */
                                     /* 8MHz / (16+2*TWBR*1) ~= 100kHz */
  TWCR |= (1 << TWEN);                                       /* enable */
}

void i2cWaitForComplete(void) {
  loop_until_bit_is_set(TWCR, TWINT);
}

void i2cStart(void) {
  TWCR = (_BV(TWINT) | _BV(TWEN) | _BV(TWSTA));
  i2cWaitForComplete();
}

void i2cStop(void) {
  TWCR = (_BV(TWINT) | _BV(TWEN) | _BV(TWSTO));
}

uint8_t i2cReadAck(void) {
  TWCR = (_BV(TWINT) | _BV(TWEN) | _BV(TWEA));
  i2cWaitForComplete();
  return (TWDR);
}

uint8_t i2cReadNoAck(void) {
  TWCR = (_BV(TWINT) | _BV(TWEN));
  i2cWaitForComplete();
  return (TWDR);
}

void i2cSend(uint16_t data) {
  TWDR = data;
  TWCR = (_BV(TWINT) | _BV(TWEN));                  /* init and enable */
  i2cWaitForComplete();
}

我从Arduino驱动器中找到了伺服控制器的地址,但我在设置电路板的PWM时遇到了问题。以下是我尝试使用的代码:

#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>
#include "i2c.h"

#define SERVO_MIN 1000
#define SERVO_MAX 2000
#define SERVO_MID 1500

#define PCA9685_ADDR 0x4

#define PCA9685_MODE1 0x0

#define LED0_ON_L 0x6
#define LED0_ON_H 0x7
#define LED0_OFF_L 0x8
#define LED0_OFF_H 0x9

int main(void)
{
  initI2C();
  setupController();
  for(int i = 1; i < 17; i++) {
    setServo(i, 0, 4026);
  }
  return 0;
}

void setupController() {
    i2cStart();
    i2cSend(PCA9685_ADDR);
    i2cSend(PCA9685_MODE1);
    i2cSend(0x0);
    i2cStop();
}

void setServo(uint8_t id, uint16_t start, uint16_t stop) {
    i2cStart();
    i2cSend(PCA9685_ADDR);
    i2cSend(LED0_ON_L+4*id);
    i2cSend(start);
    i2cSend(start>>8);
    i2cSend(stop);
    i2cSend(stop>>8);
    i2cStop();
}

这是司机: https://github.com/adafruit/Adafruit-PWM-Servo-Driver-Library

我很确定我的i2c设置不正确?有什么建议吗?

谢谢!:)