Mail Archives: geda-user/2012/04/05/00:16:55
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Peter Stuge wrote:
> It's a mux on the CS/ line of two SPI flash chips.
Oliver, I really think you should add a real mux to the PCB, and have
that be "remote controlled" by the jumper or mechanical switch.
It's a small board but I think it can be done. The design I used on
the M57SLI (see http://stuge.se/m57sli/ if curious) is shown in the
attachment, but I suggest to make some improvements:
1. change things around so that the switch common is GND
2. look for little logic to reduce component count
The attachment has two suggested circuits using little logic, one
with only two components (3306+resistorpack) but which then requires
a SPDT switch, and one with three components (3306+1g14+resistorpack)
but which only requires shorting a jumper to ground to switch between
flash chips.
//Peter
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v 20081231 1
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