Re: Working serial port.

The actiontec daughterboard uses the reset functionality built into the 
MAX3320B.  We could either do the same, or as you suggested, place a 
reset controller on the board.

Patrick M

Bruce D. Lightner wrote:

> 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
>

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