Q regarding State Machine and UPDOWN Counters.

[incisive]

Hello Friends,

I need a help with u all, 1 Q) Suppose there is a state machine for 6 States and due to few design considerations i increase my no of state machines to 12 states, how much difference would be at the gate level, i mean is there increase in only one flip flop?

for 6 states ---- no of flip flops == 3,

for 12 ..... no 0f flip flops == 4, But will there be increase in the combo logic and interconnection which varies the connection between these states, and will it effect the frequency. As far as i know there will not be increase in the frequency but the area would be quiet larger due to interconnection.

2 Q) And is it better to use a updown counter or else two counters with the same inputs affecting the counters in terms of no of gates and flip flops.

I mean is there any increase in flip flops and also no of gates and frequency.

Thanks and regards
Incisive.

 

[bansalr]

Definately the decoding logic has increased for the next state (since no of flip flop has increased.) which will result in more gates and
more combo delay causing the decrese in frequency of operation.

Using a updown counter will use n flip flops with added logic gates for operation.
but seperate counter will have 2n flip flops for the same operation one for up and one for down.

 

[semiconductorman]

These are consderations that need to be done based on the design. Increasing the number of states will increase the gate count but you usally end up getting a good timing on these circuits.

On second question if your updown counter has enough speed to suffice for your needs then you can stick to it.