Multiple clocks with synchronous design

[rajesh0therascal]

I have a 16 MHz clock on board. I need 250 Hz, 1/3 Hz and 1/21 Hz clocks for inner logic circuits to work.. I have derived 250 Hz clock in synchronous manner using clock enable. So now can I use that 250 Hz to derive rest of the clocks or should I use 16 MHz clock for clock division.

Since deriving 1/3 and 1/21 from 250 Hz clocks require counters or registers of smaller size, Im inclined to do the same.

Kindly Help..

Thank You in advance.

 

[TrickyDicky]

why do you need them as clocks - what wrong with clock enables?

 

[rajesh0therascal]

TrickDicky, That is not my question.. I'm asking whether to derive Clock enable from master clock or from the other derivatives which are already synchronous and slow.

 

[TrickyDicky]

its easier to derive them from the master clock. If you derive them from the slower clock enables, the enable will be high for a long time, unless you get them to turn themselves off (that would probably use less logic).