Search found 193 matches

by mikeb
Wed Jun 03, 2020 5:56 pm
Forum: Technical questions
Topic: Help with two Orics
Replies: 70
Views: 7102

Re: Help with two Orics

But yeah, this type of help is much appreciated, thanks a lot Mike ! I’d love to buy you a beer, Mike. Thanks once more for all the help and advice! I’ve learned a lot of the inner workings of the Oric. Beers not necessary, though thanks for the thought :) More than happy to know that Orics are get...
by mikeb
Wed Jun 03, 2020 5:40 pm
Forum: Technical questions
Topic: Help with two Orics
Replies: 70
Views: 7102

Re: Help with two Orics

kenneth wrote:
Tue Jun 02, 2020 10:58 pm
Two Orics reborn :mrgreen:
From "Do ULA!" to doula :)
by mikeb
Tue Jun 02, 2020 5:13 pm
Forum: Technical questions
Topic: Help with two Orics
Replies: 70
Views: 7102

Re: Help with two Orics

I may have suggested this, or may have forgotten, but once it is powered up, what happens if you briefly short (with a wire) CPU pin 1 (VSS) and 40 (Reset)? This forces a more enthusiastic cold reset, once power is up and stable. Sometimes, an Oric won't start because the onboard reset just didn't h...
by mikeb
Sun May 31, 2020 5:56 pm
Forum: Hardware hacks and extensions
Topic: TSN 1-2450A instead of LM7905
Replies: 2
Views: 89

Re: TSN 1-2450A instead of LM7905

These do seem like a good "modern replacement" for the 7905, and in fact not only will they run cooler as you observe, but the input current draw will also be lower (as instead of ditching the excess voltage as heat, a buck converter trades the excess voltage for greater output current). Also, the i...
by mikeb
Sat May 30, 2020 5:52 pm
Forum: Technical questions
Topic: Help with two Orics
Replies: 70
Views: 7102

Re: Help with two Orics

Turns out it was the multiplexer that was soldered onto the motherboard all along. Excellent -- I must admit that is an odd symptom to end up with, but I guess it will be filed away for future reference :) The multiplexer is supposed to swap between the low (A0-A7) part of the address output from t...
by mikeb
Sun May 24, 2020 8:48 pm
Forum: Cross development tools
Topic: How to use MACROS with OSDK
Replies: 13
Views: 266

Re: How to use MACROS with OSDK

I guess to avoid problems I could probably rename it to something that makes people not feel like using it, like "osdk_internal_compiler_stuff_do_not_user.dont_touch" :) Maybe :- "osdk_internal_compiler_stuff_do_not_user.dont_touc .h " It's a nice idea, but someone will just go "OK, I make a copy!"...
by mikeb
Fri May 22, 2020 5:31 pm
Forum: Emulators
Topic: first address read after Oric power on
Replies: 3
Views: 168

Re: first address read after Oric power on

@iss answer is technically correct, but a real 6502 spends at least the first few cycles groping around in the dark until the internal reset has completed. So there could be a few rather odd accesses before it reads from #FFFC/#FFFD and then outputs the address it finds there for the first read. Alt...
by mikeb
Sat May 09, 2020 5:02 pm
Forum: Technical questions
Topic: Help with two Orics
Replies: 70
Views: 7102

Re: Help with two Orics

Would an oscilloscope shed more light into this? I’ve got a pocket sized $10 oscilloscope from China but I don’t know if it’s actually good for anything. It might be hard to pick out anything other than fairly obvious problems -- the activity on the data lines will be fast and furious, and varying....
by mikeb
Fri May 08, 2020 3:52 pm
Forum: Technical questions
Topic: Help with two Orics
Replies: 70
Views: 7102

Re: Help with two Orics

I tried swapping the IC15 and IC16. I’m still getting the ’(’ character. I’ll probably try to source a batch of 15 ns Fujitsus. Blazing fast. Much better than the 150 ms ones suggested up thread somewhere :) Swapping IC 15/16 over, and no change to the character? I was expecting the character to ch...
by mikeb
Thu May 07, 2020 5:39 pm
Forum: General Discussion
Topic: Connectivity problems (again)
Replies: 117
Views: 15517

Re: Connectivity problems (again)

- First a long ping to defence-force.org to see the average/min/max roundtrip and number of errors/packetloss (on windows you can do ping -t defence-force.org) - Then run a traceroute/tracert from your machines to defence-force.org to see if there are anything weird, like both when it works fine an...
by mikeb
Thu May 07, 2020 5:17 pm
Forum: Technical questions
Topic: Help with two Orics
Replies: 70
Views: 7102

Re: Help with two Orics

(Looks at bare Oric board ...) For perfectly understandable reasons, you are on the wrong chip! The DRAM chips are numbered, left to right For D7, 6, 5, 4, 3, 2 1, D0 ... IC 12 ,13,14,15,16,17,18, 19 http://oric.signal11.org.uk/img/title_barepcb.jpg Only the outer two are numbered! You have taken th...
by mikeb
Wed May 06, 2020 10:20 pm
Forum: General Discussion
Topic: Connectivity problems (again)
Replies: 117
Views: 15517

Re: Connectivity problems (again)

Sorry -- it's back to painfully wading through treacle again -- only 22 guests shown, but timing out all over the place, hard to preview/post or even read threads.
by mikeb
Wed May 06, 2020 10:18 pm
Forum: Technical questions
Topic: Help with two Orics
Replies: 70
Views: 7102

Re: Help with two Orics

On the clocks etc. -- you must have a 12MHz clock (you have a coherent picture!) and further, you have a 1MHz clock out from the ULA, even if your logic probe thinks that's too fast to be "pulsing" because the machine has booted and run BASIC. Hard to do that without 1MHz clock. My diag ROM -- shoul...
by mikeb
Wed May 06, 2020 10:03 pm
Forum: Technical questions
Topic: Help with two Orics
Replies: 70
Views: 7102

Re: Help with two Orics

Excellent screen shot! That "junk" shows something important, even if it looks like rubbish. Your "D3" data line is high at times when it should not be. Observe all those ")" symbols. (Hex 0x28) that should be spaces (0x20). That's bit 3 of the data bus stuck high. Now, for the mind blower :-) Your ...
by mikeb
Mon May 04, 2020 5:50 pm
Forum: General Discussion
Topic: Connectivity problems (again)
Replies: 117
Views: 15517

Re: Connectivity problems (again)

245 guests at the top level board, but everything running ok right now, thanks!