Hi,friends
When I was learning LCU, I met a problem and I hope to get your help.
As i see it .
In Logic diagram ,if Sel = 0 ,Y == A. if Sel = 1, Y == B.
But,In Waveforms , when Sel = 1, Y != B. Why ?
Hi,
it is explained in the last sentence of the Waveforms chapter...
Writes to SWEN and SWVALUE have immediate impact on LC outputs, whereas LC inputs require input synchronization to prevent metastability.
Synchronization is 2 LCU clocks as mentioned in the figure 257. So Y has value of A or B delayed by 2 clocks. SEL value also takes effect after 2 clocks while SWEN and SWVALUE immediately.
BR, Petr
Hi,
it is explained in the last sentence of the Waveforms chapter...
Writes to SWEN and SWVALUE have immediate impact on LC outputs, whereas LC inputs require input synchronization to prevent metastability.
Synchronization is 2 LCU clocks as mentioned in the figure 257. So Y has value of A or B delayed by 2 clocks. SEL value also takes effect after 2 clocks while SWEN and SWVALUE immediately.
BR, Petr
