TCMPB填什么？

最近做PWM，查了下资料TCMPB0：
    TCMPB0                                                 Bit                            Description Initial                                     State
Timer 0 compare buffer register      [15:0]                 Set compare buffer value for Timer 0      0x00000000
但在友善之臂给的程序里：
clk_p = clk_get(NULL, "pclk");                                    //得到pclk
pclk = clk_get_rate(clk_p);
tcnt = (pclk/50/16)/freq;                                             //得到定时器的输入时钟，进而设置PWM的调制频率

__raw_writel(tcnt, S3C2410_TCNTB(0));        //PWM脉宽调制的频率等于定时器的输入时钟  
__raw_writel(tcnt/2, S3C2410_TCMPB(0));    //占空比是50%
填充的是频率。
我不解的是TCMPB里到底是填频率还是计数值。

tcnt = (pclk/50/16)/freq;  

你没觉得tcnt的单位是Hz/Hz吗？