Re: Working serial port.

"Bruce D. Lightner" <lightner-2huV/[email protected]>
Newsgroups gmane.linux.uclinux.actiontec
Message-ID <[email protected]>
Patrick:

> The #RST pin on J5 is an input, not an output.  When active (low) it 
> resets the CX82100 on the Actiontec board.  I am driving it with the 
> same reset circuit as the UART, though the signal is inverted first.

Ahhh!!!  So, can I assume that the RST# line is pulled-up on the Actiontec 
motherboard?

The fact that RST# is strictly and input implies that some kind of "reset 
controller" chip (or R/C circuit) is needed to generate a clean "reset" 
pulse on power-up.  Maybe that's what the 3-pin "transistor-looking" part 
(i.e., SOT-23) is on the Actiontec daughtercard!?  I've been burned by R/C 
reset circuits enough that I stopped using them in favor of 3-pin reset 
controllers.  They're cheap.

Clearly my present design needs some changes in this area...

> I've already got a Motorola Encore GPS board.  It's not quite as small, 
> but I'm not planning to try and fit it in the Actiontec case.

It may fit.  We used the Motorola Encore M12 long ago.  It's "old" part by 
today's standards.  However, it does work!  It drew way too much power for 
what we were doing, and did not have near the sensitivity of the GPS units 
from Trimble.

Bruce

-- 
  Bruce D. Lightner
  Lightner Engineering
  La Jolla, California
  Voice: +1-858-551-4011
  FAX: +1-858-551-0777
  Email: lightner-2huV/[email protected]
  URL: http://www.lightner.net/lightner/bruce/

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