Re: Do any octal 3 to 8 demultiplexers exist?

On Tue, 03 May 2005 18:12:25 +0000, Michael Noone wrote:

> Rich Grise <richgrise@xxxxxxxxxxx> wrote in
> news:pan.2005.05.03.15.06.22.745475@xxxxxxxxxxx:
>> So, do you want eight independent one-of-eights, or a one-of-64?
>> You could do that with 4X 74HC154, 4-to-16 decoder. That at least
>> reduces your chip count by half, albiet it's still 96 pins. And,
>> of course, you still have to select only one of them with a 2-to-4,
>> like a 74HC139.
>> http://www.standardics.philips.com/products/decoders/
>>
>> Good Luck!
>> Rich
>>
>
> I'd rather eight 1 to 8 demuxes that had their control bits tied together -
> so essentially that'd be like a 8 channel 1 to 8 demux. If I'm not being
> clear - I want to switch an 8 bit parallel signal to 8 different 8b buses.

Then you don't want demuxes at all - except the one to select your
port. Splitting up an 8-bit port into 8 ea. 8-bit ports using demuxes
would be an absolute nightmare to wire up/lay out.

If you need them latched, use 8X HC573; if they don't need to be
latched, then 8X HC244. That's the way they've been doing output
ports since time immemorial. If you need them bidirecitonal, use
HC245's.

Or, use one of those mongo PICs:
http://www.microchip.com/ParamChartSearch/chart.aspx?branchID=1095&mid=10&lang=en&pageId=74

Good Luck!
Rich


.

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