4-bit synchronous counter which is counting upwards from 3 to 12?

Sedus

Joined Mar 25, 2021
31
I guess because simulation force 0 at start.

dl324

Joined Mar 30, 2015
13,534
I guess because simulation force 0 at start.
Can you explain why the counter is able to count out of an invalid state?

Sedus

Joined Mar 25, 2021
31
I just realized if I write 3 to 0 at n+1 instead of XXXX it will start with 3.

ericgibbs

Joined Jan 29, 2010
14,189
hi S,
Recall I said in a counter it is usual to Reset/Clear all the Bistables in order the counter starts from '0000'.
This is because at Power On the individual Bistables can be Set or Clear, so when counting starts it may not be '0000'.

Consider that you wanted the counter to start at '1100' , what if you could Set 'A' and 'B' to'1' state, how would you achieve that.??

E