HW: auto-reset glitch can hang CPU on Uno R2

[GoogleCodeExporter]

What steps will reproduce the problem?
1. on an Uno R2, depending on other hardware connections on digital signals, an 
auto-reset sequence will consistently fail to start the sketch (or even the 
bootloader.)
2. scope traces show a positive (exceeding +5V) glitch on the RESET signal; if 
this was high and long enough, the AVR would enter HV programming mode; the 
theory is that the shorter glitch leaves the AVR hung.
3. a diode to VCC is a confirmed fix.

What is the expected output? What do you see instead?

Please use labels and text to provide additional information.
http://arduino.cc/forum/index.php/topic,64256.msg471812.html#msg471812

(is there a better place to report hardware bugs?)

Original issue reported on code.google.com by wes...@gmail.com on 23 Jul 2011 at 9:26

[GoogleCodeExporter]

oops; didn't mean to "accept" this before the relevant parties can review.

Original comment by wes...@gmail.com on 23 Jul 2011 at 9:28

• Changed state: New

[GoogleCodeExporter]

I was able to recreate the symptom with a standard Arduino Duemilanove, so the 
problem is not just with an Uno R2 board.  

Original comment by l...@sbcglobal.net on 23 Jul 2011 at 11:54

[GoogleCodeExporter]

This has been fixed in R3 of the board.

Original comment by dmel...@gmail.com on 16 Dec 2011 at 10:31

• Changed state: Fixed