Re: Gemini 80-Bus System
Normally when two adjacent data lines look identical with frequent half-logic levels as they do on the uppermost two images on that page, it suggests that the two lines are shorted together either physically (track short/solder splash) or by a fault in one of the devices on the bus.
The half-levels are caused by one line (say D0) trying to go high at the same time as the other (say D1) goes low. You get a high on both lines when both lines are trying to be high, a low on both lines when both are trying to be low, and a half-level when they are trying to be in opposite states.
|