AVR單片機PCF8591AD-DA實(shí)驗

//-----------------------------
uchar ADC_read(uchar chl) //讀取函數設置通道變量
{
uchar temp; //讀取值
start();
wait();
if(test_ack()!=START) return 0; //啟動(dòng)失敗返回0
write_byte(0x90); //發(fā)送寫(xiě)方向
wait();
if(test_ack()!=MT_SLA_ACK) return 0;
write_byte(0x40|chl); //發(fā)送寫(xiě)命令和通道值
wait();
if(test_ack()!=MT_DATA_ACK) return 0;
start(); //再次啟動(dòng)
wait();
if(test_ack()!=RE_START) return 0;
write_byte(0x91); //發(fā)送讀方向
wait();
if(test_ack()!=MR_SLA_ACK) return 0;
twi();
wait();
if(test_ack()!=MR_DATA_NOACK) return 0;
temp=TWDR;
stop();
return temp;
}
//------------------------------------------------
uchar ADC_write(uchar data)
{
start();
wait();
if(test_ack()!=START) return 1;
write_byte(0x90); //啟動(dòng)寫(xiě)方向
wait();
if(test_ack()!=MT_SLA_ACK) return 1;
write_byte(0x40); //模擬量輸出設定
wait();
if(test_ack()!=MT_DATA_ACK) return 1;
write_byte(data); //模擬量輸出值
wait();
if(test_ack()!=MT_DATA_ACK) return 1;
stop();
delay(10); //延時(shí)10ms 等待發(fā)送好
return 0;
}