Skip to main content ↑ ↓
Topic: Improper signal inversion (Read 1036 times) previous topic - next topic

Improper signal inversion

I am two days into fiddling with the logic sniffer v 1.04 that I got earlier this week.  I am using Jawi's 0.9.6.1 client under linux
(Fedora 18, a 3.9.6 kernel).  I am looking at signals from an old MC68010 cpu board.  In particular, I am monitoring
HALT* and RESET* (both are active low), and I set up a trigger on reset to do a capture when reset transitions from low to
high (and this works perfectly).  What is truly odd is that the capture shows both of these signals transitioning from
high to low, which is exactly wrong.  A meter shows RESET* as 5.0 volts when the CPU is running, which is as it should
be, but the sniffer shows this signal as a low.  The fact that the trigger worked properly is certainly in conflict with what I
see on the display.  Anybody ever seen anything like this?