Project 3: Clock as input to a subcircuit?

[Daniel Ritchie]

As long as every clock you use has the same period, you wouldn't have any
problems by putting a clock in each subcircuit that needed it. However, I
don't think that's good practice. It's probably better to have every element
managed by a single clock (since that's what happens in an actual, physical
CPU, as far as I know).

Should we attempt to make our clock an input to our subcircuits, say by
having
a 1 bit input, that we then wire to the clock in our main circuit?
Or should we just put a clock in every subcircuit in which they are
needed?
-Paul

[Alex Sydell]

All of the clocks in logisim run at the same frequency, so it really
doesn't matter. Putting in multiple clocks is pretty much still just
putting in a single one because you can't set them to different
frequencies. I'd say save yourself the hassle and just put them in
separately wherever they're needed.

Should we attempt to make our clock an input to our subcircuits, say by having
a 1 bit input, that we then wire to the clock in our main circuit?
Or should we just put a clock in every subcircuit in which they are needed?
-Paul

[David Schleimer]

Actually, you can set different clocks to run at different frequencies.
The tick frequency menu option on the simulate menu isn't directly
tied to the clock frequency. The number of ticks each clock stays up
for and stays down for can be set independently of each other as well as
of all other clocks to be any number of ticks you want.

David

Post by Alex Sydell
All of the clocks in logisim run at the same frequency, so it really
doesn't matter. Putting in multiple clocks is pretty much still just
putting in a single one because you can't set them to different
frequencies. I'd say save yourself the hassle and just put them in
separately wherever they're needed.

Should we attempt to make our clock an input to our subcircuits, say by having
a 1 bit input, that we then wire to the clock in our main circuit?
Or should we just put a clock in every subcircuit in which they are needed?
-Paul

[Mark Landry]

I do not use multiple clocks because it means you need to ctrl-t to get all
the clocks to move. Having just one clock means you can click on the actual
clock instead.

[[TA] Benjamin Sussman]

PIPE THE CLOCKS IN!!! Whew! Lots of reponses say "it doesn't matter"
but this is NOT TRUE for two reasons:

1. In actual hardware, the clock is (relatively) big hunk of stuff
(crystal oscillator) which would not make sense to duplicate multiple
times on your circuit.
2. Logisim sucks, and could cause problems even if your multiple clocks
LOOK like they're synchronized.

Ok, that said, if Logisim screws up MORE when you pipe the clock
instead of what you were doing before (which was duplicating the clock)
then feel free to do the solution which screws up less. However, i
doubt this will occur, and in my experience Logisim handles piped
clocks better than duplicated clocks.

Ben

Post by Mark Landry
I do not use multiple clocks because it means you need to ctrl-t to get all
the clocks to move. Having just one clock means you can click on the actual
clock instead.