18 Mar
2017
18 Mar
'17
5:21 p.m.
Hi folks,
8085-based phone system weirdness continues and I'm beginning to wonder if
the PSU rails are all coming up in time for RESET to go high - given there's
4116 DRAMs in there isn't there supposed to be a proper power up order?
While I look at using a 20-pin ATX PSU to run this machine temporarily I
need a safe way to reset the CPU rather than constantly power cycling. The
RESET line comes from an ICL7611 op-amp via an MC14081B through pins 1-4 of
a 74LS04 and I need to pull it low for longer than 3 clock cycles.
I wish I had a schematic to show!
Cheers,
--
Adrian/Witchy
Binary Dinosaurs creator/curator
Www.binarydinosaurs.co.uk - the UK's biggest private home computer
collection?