51单片机控制PCA9685源程序 -

/* PCA9685驱动程序 */
/* 使用IO口模拟通信 */
/* 16路PWM输出 */
#include<reg52.h>
#include<intrins.h>
sbit SCL=P1^0; //定义时钟引脚
sbit SDA=P1^1; //定义数据引脚
#define PCA9685_adrr 0x80//1+A5+A4+A3+A2+A1+A0+w/r
#define PCA9685_SUBADR1 0x2
#define PCA9685_SUBADR2 0x3
#define PCA9685_SUBADR3 0x4
#define PCA9685_MODE1 0x0
#define PCA9685_MODE2 0x1
#define PCA9685_PRESCALE 0xFE
#define pwm0_ON_L 0x6
#define pwm0_ON_H 0x7
#define pwm0_OFF_L 0x8
#define pwm0_OFF_H 0x9
#define ALLpwm_ON_L 0xFA
#define ALLpwm_ON_H 0xFB
#define ALLpwm_OFF_L 0xFC
#define ALLpwm_OFF_H 0xFD
void iic_delay()//延时5us
{
_nop_();
_nop_();
_nop_();
_nop_();
_nop_();
}
void iic_start()//scl高电平区间，sda一个下降沿启动信号
{
SDA=1;
iic_delay();
SCL=1;
iic_delay();
SDA=0;
iic_delay();
SCL=0;
iic_delay();
}
void iic_stop()//scl在高电平区间，sda一个上升沿信号
{
SDA=0;
iic_delay();
SCL=1;
iic_delay();
SDA=1;
iic_delay();
}
void iic_wait_ack()//在scl高位时，从机拉低sda引脚表示应答
{
unsigned char i=0;
SCL=1;
iic_delay();
while((SDA==1)&&(i<255))
{
i++;
}
SCL=0;
iic_delay();
}
void iic_init()//初始化IIC通讯引脚
{
SCL=1;
iic_delay();
SDA=1;
iic_delay();
}
void iic_send_ack(bit iic_ack)//接受完成之后，发送应答位，0应答继续发送，1不应答停止发送
{
SDA=iic_ack;
SCL=1;
iic_delay();
SCL=0;
iic_delay();
}
void iic_write_byte(unsigned char iic_byte)
{
unsigned char i=0;
for(i=0;i<8;i++)
{
SCL=0;
iic_delay();
SDA=iic_byte&0X80;
iic_byte=iic_byte<<1;
iic_delay();
SCL=1;
iic_delay();
}
SCL=0;
iic_delay();
SDA=1;
iic_wait_ack();
}
void iic_write(unsigned char slave_addr,unsigned char iic_addr,unsigned char iic_byte)
{
iic_init();
iic_start();
iic_write_byte(slave_addr);
iic_write_byte(iic_addr);
iic_write_byte(iic_byte);
iic_stop();
}
unsigned char iic_read_byte()//读字节，先读高位，左移
{
unsigned char i=0;
unsigned char iic_byte=0;
SCL=0;
iic_delay();
SDA=1; //确保主机释放SDA
iic_delay();
for(;i<8;i++)
{
iic_delay();
SCL=1;
iic_delay();
iic_byte=(iic_byte<<1)|SDA;
SCL=0;
}
iic_delay();
return iic_byte;
}
unsigned char iic_read(unsigned char slave_addr,unsigned char iic_addr)
{
unsigned char iic_byte;
iic_init();
iic_start();
iic_write_byte(slave_addr);
iic_write_byte(iic_addr);
iic_start();
iic_write_byte(slave_addr|0x01);//发送设备地址+读信号
iic_byte=iic_read_byte();
iic_send_ack(1);//发送非应答信号
iic_stop();
return iic_byte;
}
void pca_set_freq()//频率设置为50hz(20ms)
{
unsigned char prescale=132,oldmode,newmode;
iic_write(0x80,0x00,0x0);
oldmode=iic_read(0x80,0x00);
newmode=(oldmode&0x7F)|0x10;
iic_write(0x80,0x00,newmode);//进入sleep
//设置频率时pca9685应该进入睡眠状态
iic_write(0x80,0xFE,prescale);
iic_write(0x80,0x00,oldmode);//退出sleep
iic_write(0x80,0x00,oldmode|0xA1);//立即重启
}
void pca_set_pwm(unsigned char channel,unsigned char angle)
{
unsigned int off=102+(angle*2.27);
iic_write(0x80,0x06+4*channel,0);
iic_write(0x80,0x07+4*channel,0);
iic_write(0x80,0x08+4*channel,off);
iic_write(0x80,0x09+4*channel,off>>8);
}
void delay(unsigned char delay_a) //@11.0592MHz
{
while(delay_a)
{
unsigned char delay_b=255;
while(delay_b)
{
iic_delay();
iic_delay();
delay_b--;
}
delay_a--;
}
}
int main()
{
pca_set_freq();
delay(155);
pca_set_pwm(0,40);
pca_set_pwm(1,40);
delay(155);
pca_set_pwm(0,140);
pca_set_pwm(1,140);
delay(155);
pca_set_pwm(1,150);
delay(155);
pca_set_pwm(1,47);
delay(155);
pca_set_pwm(0,70);
while(1);
}

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