关于PWM，S3C2440,timer

ddh19

关于PWM，S3C2440,timer [复制链接]

要使得TOUT1的输出频率是25MHZ，作了如下配置：
//step1
s2440IOP->rGPBCON &=~(3<<2);
        s2440IOP->rGPBCON |=(2<<2);//        set GPB1 as TOUT1
//step2
//PWM set
        s2440PWM->rTCON &=(~(0xf<<8)) ;// clear manual update bit, stop Timer1
//step3:
s2440PWM->rTCFG0 &= 0xffffff00;        // set Timer 0&1 prescaler 0       
        s2440PWM->rTCFG1 &=0xffffff0f;                // set Timer 1 MUX 1/2          
//step4:
        s2440PWM->rTCNTB1 =   ?? ;
        s2440PWM->rTCMPB1 =   ?? ;
//step5

        s2440PWM->rTCON &= (~(0xf<<8));
        s2440PWM->rTCON | (0x0e<<8) ;       
       
        s2440PWM->rTCON &= (~(0xf<<8));
        s2440PWM->rTCON | (0x0d<<8) ;      //start timer1
------------------------------------------------------------------
参考资料：
4-bit divider settings        Minimum resolution  Maximum resolution   Maximum interval
                         (prescaler = 0)    (prescaler = 255)     (TCNTBn = 65535)

1/2 (PCLK = 50 MHz) 0.0400 us (25.0000 MHz) 10.2400 us (97.6562 KHz) 0.6710 sec
1/4 (PCLK = 50 MHz) 0.0800 us (12.5000 MHz) 20.4800 us (48.8281 KHz) 1.3421 sec
1/8 (PCLK = 50 MHz) 0.1600 us ( 6.2500 MHz) 40.9601 us (24.4140 KHz) 2.6843 sec
1/16 (PCLK = 50 MHz) 0.3200 us ( 3.1250 MHz) 81.9188 us (12.2070 KHz) 5.3686 sec
--------------------------------------------------------------

Timer input clock Frequency = PCLK / {prescaler value+1} / {divider value}
{prescaler value} = 0~255
{divider value} = 2, 4, 8, 16
----------------------------------------------------

问题：//step4:
        s2440PWM->rTCNTB1 =   ?? ;
        s2440PWM->rTCMPB1 =   ?? ;
中的两项怎么设置？

xiongjunfeng

[code]
4-bit divider settings        Minimum resolution  Maximum resolution     Maximum interval
----------------------- (prescaler = 0)    (prescaler = 255)       (TCNTBn = 65535)

1/2 (PCLK = 50 MHz) 0.0400 us (25.0000 MHz) 10.2400 us (97.6562 KHz) 0.6710 sec
1/4 (PCLK = 50 MHz) 0.0800 us (12.5000 MHz) 20.4800 us (48.8281 KHz) 1.3421 sec
1/8 (PCLK = 50 MHz) 0.1600 us ( 6.2500 MHz) 40.9601 us (24.4140 KHz) 2.6843 sec
1/16 (PCLK = 50 MHz) 0.3200 us ( 3.1250 MHz) 81.9188 us (12.2070 KHz) 5.3686 sec

qu27jump

居然没有人来

lhmymc

s2440PWM->rTCNTB1与周期有关，s2440PWM->rTCMPB1与占空比有关。

valengu

早就解决了
没来结贴，送分了

liangzuolin

怎么解决的，说说方法啊