Trouble with the ATMega128 and Micro Dual Motor Controller

Hi there,
I’ve used the micro dual serial motor controller with a BASIC Stamp module a number of times and I’m attempting to transition to using an ATMega128-based board (specificially, a Robostix board from Gumstix). I can confirm independantly that the pin I’m using for reset is going low/high and that the UART is outputting the correct serial commands using a USB-serial interface. I’ve already dropped the default baud for UART1 on the Robostix to 9600 (a speed I can confirm working since it uses the same on the BASIC Stamp - the default speed on the Robostix is higher than the autodetect on the dmsmc).

I just can’t seem to get these two to work even though exactly the same things are being output from the BASIC Stamp that I test on and the Robostix. Has anyone else used the same controller that would like to share any wisdom to get them working together?



One thing that might be different between your Stamp and Robostix is the delay between the reset line going high and the serial data coming out. You could have problems if you begin sending serial before the motor controller is ready. It would be good to look at the two sets of signals with an oscilloscope since there is apparently something different coming out of your Robostix.

- Jan