Search found 6 matches

by Vampire
Sat Jul 22, 2017 11:23 am
Forum: Technical questions
Topic: Clock problems
Replies: 3
Views: 4002

Re: Clock problems

Hi Chema/Godzil, Good call on the probe capacitance. I tried again with the probes set to x10 (and I don't know why I didn't think to try that earlier as I remembered having to do something similar in the past with the Oric) and got this... Bad Trigger Small.jpg From this you can clearly see that th...
by Vampire
Wed Jul 19, 2017 10:30 pm
Forum: Technical questions
Topic: Clock problems
Replies: 3
Views: 4002

Clock problems

So I'm trying to connect an Oric Atmos up to an FPGA, but I'm having some problems with the clock. I was seeing some odd false triggering, so I've tried running Ø2 through a 74HCT244, but this is where it starts to get odd. Let me share the scope traces. In all traces yellow is the Oric's Ø2 line as...
by Vampire
Sat Apr 24, 2010 4:05 pm
Forum: Technical questions
Topic: Expansion port 5V ampage
Replies: 7
Views: 7408

I had (as with most people) assumed that the internal speaker could only be disabled in two ways. Either physically removing it or placing a rather questionable short across the sound output on the Cassette port connectors. :? I've been looking at the schematic here , and its pretty ropey. I can't ...
by Vampire
Thu Apr 22, 2010 11:45 pm
Forum: Technical questions
Topic: Expansion port 5V ampage
Replies: 7
Views: 7408

Cool. I'll get that all sorted over the weekend. I'll include the sample code I've done for detecting the VSync too. I couldn't find it anywhere else on the site, so I kinda borrowed from Buggyboy ;) I've just finished boxing it all up, which includes my little switchable VSync box too, and it works...
by Vampire
Thu Apr 22, 2010 7:11 am
Forum: Technical questions
Topic: Expansion port 5V ampage
Replies: 7
Views: 7408

Yeah, thats the one I've made. I just decided to bite the bullet and go with board power. There have been no ill effects so far. The image quality is excelent. Had two issues to begin with though. One was my TV (only one of the scart inputs is RGB, the other only supports composite) and the other wa...
by Vampire
Wed Apr 21, 2010 10:36 am
Forum: Technical questions
Topic: Expansion port 5V ampage
Replies: 7
Views: 7408

Expansion port 5V ampage

I've made up a SCART converter + tape VSync box from my Atmos, the 74HCT244 one. Looking at the expansion port specs, its got a 5v line on it, so I was thinking about using that instead of an external power supply. I have no idea how much drain that converter puts on the external PSU, or how much in...