I know you can fry a USBtinyISP if you short an output and it draws too much current, better the USBtinyISP blows than your motherboard.
Post a schematic - I didn't see any mention of diodes across the motors.
(how would you burn the program without a programmer :-S )
Quote from: CrossRoads on Oct 27, 2012, 04:07 amPost a schematic - I didn't see any mention of diodes across the motors.Thanks for the suggestion! It's an H-bridge going both ways -- I can't really use diodes there. The N-channel MOSFETs (high and low -- driven by IRS2301 drivers) have built-in body diodes that go the way they can go.
Quote from: fungus on Oct 27, 2012, 06:40 pm(how would you burn the program without a programmer :-S )Exactly my problem :-)
Those "body diodes" aren't acceptable as flyback diodes
You can use ArduinoISP to burn the firmware
The arrangement you suggest is exactly the same arrangement that the body diodes is providing, right? Your suggestion is that the body diodes are poor performance as flyback diodes, and I should double them up with something better? Can I use some 1N4001s? Do I need a high-voltage Schottky? Something else?
Those "body diodes" aren't acceptable as flyback diodes (I say, "No Way!")
Something like 1000uF electrolytic