01-02-2016, 06:30 PM
If anyone has done a detailed analysis of that schematic they will find that I've actually got the Q1 and Q0 inputs to the '138 the wrong way round to avoid glitches. I re-did the timing diagrams and worked it out again from scratch. Because Q1 always changes later than Q0 (it's a ripple counter) then the safe epoch is when Q1=0 and Q0=1. Q0=Q1=1 is also safe but that doesn't give much timing margin from when Q2 and Q3 can change.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
