From: Andreas Zwirtes <zwirtes_at_gmx.de>
Date: Tue, 15 Oct 2002 19:06:38 +0200

Stuart Tedford wrote:

>Yes, I think we are on the same track too.
>
Great! Seems like Andrew has a lot of mails to read, when he's back ;)

>It sounds like you have thought through most of the hardware basics now.
>
I think I did. Because of my job I know a lot about battery driven
devices. We build remote transmitters for cars and have to deal with
similar problems very often.

>As for you bi-dir PC coms, could you email me a schematic of the cable you
>use?
>
Sorry, but I've only written it on paper and no scanner here. But I'll
try to get my hands on the Eagle freeware and draw the schematic. That'd
also be much better for publishing ;). If it doesn't work out, I'll send
you a scan. Do you have a preferred schematic and PCB layout program?

>And for the Archos side of things, I like the suggestion from the post
>subject:"to send data to a remote via RxD1" on this several days ago. That
>would use a TPU kind of function to tx the data, if it works, that would be
>more efficient than bit bashing the pin.
>
Yes, I thought about that. The problem is, that the TPU or any other
synchronous serial transmitter hardware would switch the port between
Vcc and GND. And that switching to Vcc is something, that we should
avoid at all cost. I don't want anyboby making me responsible for
blowing up his processor ;). The only way to do this is, as I see it,
bit banging the port and switch between low and floating.

> I just wish i had more spare time
>- "some day soon (tm)".
>
Yeah, me too!

Andreas
Received on 2002-10-15