Serial communication with Arduino erratic behavior.

[marcuso]

I had issues with certain behaviour being different depending on whether I had the robo claw plugged in to the USB on my PC (even though the robo claw wasn't doing anything - don't forget the power is never drawn from USB - ever - power only comes to the RoboClaw from an ext source for logic), so I upgraded the firmware on the board to the new 1.7.0 and it started working. Now this could be for 2 reasons - firstly a firmware upgrade might reset all the settings on the board - maybe I had an invalid/incompatiable setting and this was reset to default post upgrade, or bugs were fixed in 1.7.0 and the board was showing the effects of a bug. so my advice is to minimise the baud rate, reset to default and change one setting at a time to see what impact it has, and then if all else fails upgrade the firmware. I had 3 flashing lights on err - red, mine disappeared and I havent had a problem since.

Marcus

[Basicmicro Support]

Also, use the latest arduino library. It now uses the arduinos own software serial class or hardware serial class. The latest version of the software serial class seems to work very well(good timings).