OWFS on $WRT-router

Kyle Bassett kylebassett at gmail.com
Mon Feb 4 19:38:09 CET 2008


I understand you had posted to the incorrect mailing list, but your question
intrigued me.  The first link in the question does not work, is that the
correct link?

And for a UART, you definitely need level shifting (ie. like a MAX232, etc.)
if connecting to +/-12v serial line, at the very least to avoid damaging the
UART by overvoltage.  In some cases, it is possible to do w/o the level
shifting, due to the requirements in the RS-232 specs for the RX line of
most UARTs, which are required to distinguish signals as low as +/-3v.
Results are varied, as not every manu. follows the specs. verbatim.

-Kyle Bassett

On Feb 3, 2008 6:11 PM, Chris <lists at proquariat.de> wrote:

> Hi,
> I tried this: http://owfs.sourceforge.net/WRT54G.html and it doesn't
> work for me.
> It looks really weird how the author connected the DS2480B, which runs
> at 5V directly to the UART, which provides only 3.3V. I think this would
> need some level-shifting.
> The datasheet also says the POL-Pin (Pin6) has to be tied to +5V if
> directly connected to the UART.
> I made a small schematic with some resistors as level shifters:
> http://img228.imageshack.us/img228/4611/ds2480bwrtmp0.png but I don't
> think I like it. It's said that doing level shifting is very power hungry.
> Any better ideas?
> -Chris
> _______________________________________________
> OpenMoko community mailing list
> community at lists.openmoko.org
> http://lists.openmoko.org/mailman/listinfo/community
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.openmoko.org/pipermail/community/attachments/20080204/e0711eb3/attachment.htm 

More information about the community mailing list