Working dual-clock speeds
Dan Michaels email (remove spam text)
Olin Lathrop wrote:
>> Ya missed the point - this is not to do a low power lashup like Roman,
>> but to find an easy way to select between 2 different external clocks,
>> without having to use a lot of extra logic.
>OK, but why would you want to use the low clock rate except to save power?
In this particular case, the idea was to have easy control over
"sampling rate" of some fast RAM - not to clock a microprocessor.
Seemed like a natural extension to what Roman was talking about.
Even with a fast Scenix, it is hard to get a 20Mhz controllable
clock output, but with the ECS chip [only 8-pin] you can get 20,
10, and 5 Mhz, and then use the uC for slower timing. Problem is,
with the ECS chip, 20Mhz [nondivided] comes out one pin and
10/5/... [divided] comes out another pin.
You can always use AND gates for switching, but I was hoping
for something simpler. Rich Ottosen may be onto it.
- dan michaels
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