Hi all. I have a beaglebone, as previously noted, and I am trying to connect it to an arduino and a Pololu Servo controller over TTL Serial. The Beagle wants 3.3V logic level and the arduino and pololu run on 5V. I picked up a TXB0108 breakout from Adafruit (http://www.adafruit.com/products/395
) but I'm having trouble getting it to work. Does anyone here have experience with this?
I've connected it I think correctly, with 3.3V to VCCA, and 5V to VCCB, and OE connected to VCCA. When I connect 3.3V to one of the input pins I get 5V on the output pins. The problem arises when I start sending serial TTL signals.
Here's scope output of my 3.3V serial TTL Tx signal coming out of the beagle, while I'm sending data over the linehttps://www.dropbox.com/s/0ya065hzw6dd7 ... .23.24.jpg
Here's scope output of both the 3.3V TTL Tx signal from the beagle and the output pin of the level shifter, while I am not sending data over the line... everything looks copacetic:https://www.dropbox.com/s/grndixk3xs69h ... .23.40.jpg
(the yellow line is the output pin of the level shifter, the blue line is the Tx signal from the beagle)
However, when I start sending bits over the serial line from the beagle, everything goes haywire. Even the signal on the line from the beagle looks wonky:https://www.dropbox.com/s/r7a7ff7xfid43 ... .23.53.jpg
Anyone have ideas on this one?