TTL/CMOS serial communcations compatible?

Archiver

I'm trying to use the BASIC Stamp(via TTL) to communicate to a
embedded processor which communicates via CMOS. I'm able to receive
data from the embedded device however I am not able to transmit from
the Stamp to the device. Does anybody know why this is? How do I go
about fixing this problem? Thanks!

Archiver

You need a 5 to 3 volt level-converter like the motorola HC244 or
HC245 (among others). Remamber to make a 3 volt power supply.
Or try 3 to 12 volt converter Max3232cpe, and use port 16 on the
sramp. Or two resistors deviding the signal between 2.9-3.1 volt.
(not recomended)

The stamp can recive both 5 and 3 volt serial signals.

The divice could be dameged if you try communicate at 5 volt.

Stein.


--- In basicstamps@yahoogroups.com, "andio310" <andio310@y...> wrote:
> I'm trying to use the BASIC Stamp(via TTL) to communicate to a
> embedded processor which communicates via CMOS. I'm able to
receive
> data from the embedded device however I am not able to transmit
from
> the Stamp to the device. Does anybody know why this is? How do I
go
> about fixing this problem? Thanks!