一道华为笔试题
![在这里插入图片描述](https://img-blog.csdnimg.cn/2020040120151824.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjYwMjI0Nw==,size_16,color_FFFFFF,t_70)
1.tclk最小周期tclk_min
tclk_min=Tsu_ff1+Thod_ff2+t_logic+t_net-时钟偏斜
![在这里插入图片描述](https://img-blog.csdnimg.cn/20200401201803176.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjYwMjI0Nw==,size_16,color_FFFFFF,t_70)
2.时钟建立时间Tsu
Tsu理解为正确采样数据的时间,那肯定要加上T_data_delay,再加上FF本身的建立时间。
再考虑,clk是否准时到达呢?clk如果有delay,还要再减去clk_delay
Tsu=T_data_delay+T_su_ff-T_clk_delay
![在这里插入图片描述](https://img-blog.csdnimg.cn/20200401202103755.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjYwMjI0Nw==,size_16,color_FFFFFF,t_70)
3. 时钟保持时间Thold
保持时间和建立时间相反,还是要加上FF的hold时间,不过变成了clk delay-data delay
Thold=T_clk_delay-T_data_delay+T_su_ff
![在这里插入图片描述](https://img-blog.csdnimg.cn/20200401202609778.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjYwMjI0Nw==,size_16,color_FFFFFF,t_70)
4.时钟输出延时Tco
理解:tco是clock到output的T,所以tclk+tdata+tmicro=Tco
![在这里插入图片描述](https://img-blog.csdnimg.cn/20200401203347169.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjYwMjI0Nw==,size_16,color_FFFFFF,t_70)
5. slack
![在这里插入图片描述](https://img-blog.csdnimg.cn/2020040120370874.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjYwMjI0Nw==,size_16,color_FFFFFF,t_70)
![在这里插入图片描述](https://img-blog.csdnimg.cn/20200401204837708.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjYwMjI0Nw==,size_16,color_FFFFFF,t_70)
理解:保持时间不够主要是因为Tclk delay-Tdata delay<0
![在这里插入图片描述](https://img-blog.csdnimg.cn/20200401204906603.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjYwMjI0Nw==,size_16,color_FFFFFF,t_70)
6.时钟偏斜
![在这里插入图片描述](https://img-blog.csdnimg.cn/2020040120531364.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjYwMjI0Nw==,size_16,color_FFFFFF,t_70)
答案
![在这里插入图片描述](https://img-blog.csdnimg.cn/20200401201554330.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjYwMjI0Nw==,size_16,color_FFFFFF,t_70)
选C
Reference
https://wenku.baidu.com/view/8c53f9105f0e7cd18425364c.html