EEPW论坛

问 好奇怪哦，我没看到有哪一段代码对Beep那个管脚进行操作啊？
定时器2中断服务里面就这一条指令
rI_ISPC=BIT_TIMER2;//clear timer2 interrput pending of BIT_TIMER2

难道只有GPE5(Beep)才能输出PWM？

就这段代码Beep就发出声音了
void SetBeepPwm(unsigned short Freq, unsigned char HiRatio)
{
    rTCON      &= 0xffff0fff;            // clear manual update bit, stop Timer2
    rTCFG0     &= 0xffff00ff;            // set Timer 2&3 prescaler 0
    rTCFG1     &= 0xfffff0ff;            // set Timer 2 MUX 1/16
    rTCFG1  |= 0x00000300;    
    rTCNTB2     = MCLK/(Freq*16);            //if set inverter off, when TCNT2<=TCMP2, TOUT is high, TCNT2>TCMP2, TOUT is low
    rTCMPB2  = (rTCNTB2*(100-HiRatio))/100;    //if set inverter on,  when TCNT2<=TCMP2, TOUT is low,  TCNT2>TCMP2, TOUT is high
//    rTCON    |= 0x00002000;            // manual update
    rTCON    &= 0xffff0fff;            // clear manal update bit
    rTCON   |= 0x0000d000;            // auto reload, inverter on, start Timer 2
}



答 1: 兄弟！你说对了，这段只有在GPE5才有PWM输出很多东西不一定是只有你看到才算发生了，看一下硬件手册吧