Possible problem with gumstix/robostix interface

[JonHylands]

I got a CM-5 to test my AX-12's finally, and it appears that the non-responsiveness of my AX-12's might actually be a problem with the Rx port on the Robostix - I will be investigating that this weekend, and will update on what I find.

If it ends up being the problem, I will update here, and change the design to use a bus switch.

- Jon

[JonHylands]

Well, there isn't anything wrong with the UART on the robostix.

My brother wrote a simple echo program, and I was able to run characters through both UARTs on the robostix.

When I hook the robostix up to the AX-12, and put a logic analyzer on the bus data line, nothing happens when I send a command down (the line stays high).

If I unplug the servo, and then send a command down, I can see the data line transition a bunch of times.

Definitely something weird going on...

Anyone have any ideas?

- Jon

[inaki]

I assume do you have the bus set to high with a pull-up resistor to 5V, I am right ?

If so, when you send a command, do you see the signal going down and up ?

I am not talking about reading by now, just writing ?

[JonHylands]

Boy, do I ever feel like a moron.

inaki, your post made me look at my breadboard a little closer, and I realized I had it wired wrong !!!

Fortunately, the mistake was not fatal...

Everything is working as it should now.

- Jon