Search found 105 matches

by CommanderCoder
Wed Dec 02, 2020 9:05 am
Forum: acorn atom and acorn system series
Topic: Yet Another Acorn Atom Repair
Replies: 51
Views: 2221

Re: Yet Another Acorn Atom Repair

I tested it for an hour or so and it went off again. Let it cool and its back. I'm not good with analogue electronics, so what is a good way to see if any part is drawing too much current or something like that? I noticed the switch I tried got warm too, so I'm wondering if the Atom RAM is drawing t...
by CommanderCoder
Tue Dec 01, 2020 12:55 pm
Forum: acorn atom and acorn system series
Topic: Yet Another Acorn Atom Repair
Replies: 51
Views: 2221

Re: Yet Another Acorn Atom Repair

HA.. turned it on this lunchtime just to see; and it works again.

I guess it cooled off overnight!

I'll run some memory tests on it and leave it on for a few hours!

*CONFUSED*
by CommanderCoder
Mon Nov 30, 2020 10:56 pm
Forum: acorn atom and acorn system series
Topic: Yet Another Acorn Atom Repair
Replies: 51
Views: 2221

Re: Yet Another Acorn Atom Repair

So my Atom was working fine until tonight. I wired up a 6 pin din socket to the video connector PL4 using 6 wires of a 10-way idc and plugged it in. The signal was fine and I could see a picture but it was full of "@" symbols. I removed the IDC and for the rest of these tests I used just composite v...
by CommanderCoder
Sat Nov 28, 2020 5:37 pm
Forum: 8-bit acorn emulators
Topic: Beebem OS X
Replies: 19
Views: 545

Re: Beebem OS X

Yes. I'm still working on it when I have time. Always happy to hear improvements and suggestions.
by CommanderCoder
Tue Nov 24, 2020 3:36 pm
Forum: acorn atom and acorn system series
Topic: New AtoMMC board: V4
Replies: 57
Views: 1666

Re: New AtoMMC board: V4

It's one of these that I found in the bottom of a drawer. I may have loaded it with a bit too much solder!

https://uk.rs-online.com/web/p/slide-switches/0337497/
by CommanderCoder
Mon Nov 23, 2020 6:49 pm
Forum: acorn atom and acorn system series
Topic: New AtoMMC board: V4
Replies: 57
Views: 1666

Re: New AtoMMC board: V4

Different question about the Atom : is the memory, cpu, etc.. sensitive to current changes? I added an off/on switch to my power and the Atom crashes a lot and there is corruption on the main menu screen for the *MENU. I took out the power switch and there were no errors.
by CommanderCoder
Fri Nov 20, 2020 7:44 pm
Forum: 8-bit acorn emulators
Topic: BeebEm Mac - Info
Replies: 200
Views: 19176

Re: BeebEm Mac - Info

Updated version of BeebEm5 (aka BeebEm4 for mac, but actually more like an updated BeebEm3 looking at the Jon Welch 4.0a codebase that it is based on.) It supports 'double click' on a disk or tape file to boot it into the emulator (no drag and drop yet). It has a DMG but you still need to allow it t...
by CommanderCoder
Fri Nov 20, 2020 7:41 pm
Forum: acorn atom and acorn system series
Topic: New AtoMMC board: V4
Replies: 57
Views: 1666

Re: New AtoMMC board: V4

Thanks to SirMorris I have a working PIC chip now and the Acorn Atom is fully working with an SD card. So excited to compare it with my emulator. I will have to put the 'snow' into the emulator now though; to get it a bit more authentic.
by CommanderCoder
Mon Nov 16, 2020 7:29 pm
Forum: acorn atom and acorn system series
Topic: New AtoMMC board: V4
Replies: 57
Views: 1666

Re: New AtoMMC board: V4

Is there a physical mod I could make in the meantime? Is the IRQ on a different line from the PIC and I could connect that to LK3?
by CommanderCoder
Mon Nov 16, 2020 4:59 pm
Forum: 8-bit acorn emulators
Topic: BeebEm Mac - Info
Replies: 200
Views: 19176

Re: BeebEm Mac - Info

I saw and I'm on the case. I'd been spending a bit of time looking at 'DoubleClick' to get a recognised file to load at the same time as the app starts up. Not important but... I think distributing a DMG is probably the next thing to sort out, and incorporate recent changes made in the Windows BeebE...
by CommanderCoder
Mon Nov 16, 2020 9:18 am
Forum: acorn atom and acorn system series
Topic: New AtoMMC board: V4
Replies: 57
Views: 1666

Re: New AtoMMC board: V4

I can start up the AtoMMC2 with LINK #AFCC I tried removing the SD Card, inserting and pressing BREAK; no change. *CFG returned E0 -- Can I update the Firmware with a file or will I need a PIC programmer? I can use a RPi if that can do it. I may have an old PIC programmer but I'm not sure it would t...
by CommanderCoder
Sun Nov 15, 2020 9:45 pm
Forum: acorn atom and acorn system series
Topic: New AtoMMC board: V4
Replies: 57
Views: 1666

Re: New AtoMMC board: V4

I connected the link (LK3) and still no joy. The only way I can get it to start up is by touching LK3 to ground.

I've put a logic analyser on Pin4 of the CPU and it never goes low (including BREAK, etc). Could it be the pull up resistor? It reads as a 4.7kohm resister with my multimeter.
by CommanderCoder
Sat Nov 14, 2020 11:59 pm
Forum: acorn atom and acorn system series
Topic: New AtoMMC board: V4
Replies: 57
Views: 1666

Re: New AtoMMC board: V4

Hurray - almost. I double checked the connections and pin 13 of ic23 was not making a good connection (that's #A000). I fiddled around with the socket and pins on the ic and now the Atom no longer hangs. However, it didn't show + ATOMMC2 on the screen either. I tried BREAK + SHIFT / CTRL / REPT and ...
by CommanderCoder
Sat Nov 14, 2020 10:38 pm
Forum: acorn atom and acorn system series
Topic: New AtoMMC board: V4
Replies: 57
Views: 1666

Re: New AtoMMC board: V4

To get the CRC I moved the EPROM to IC21 and ran the program on #d000 I gave it go removing the FP, no change. Pressing REPT key - mostly just fuzz/garbage on screen. Maybe I've got a cross connection on IC24 somewhere. It was running fine until I put in the EPROM. The system with FP, OS/BASIC, AtoM...
by CommanderCoder
Sat Nov 14, 2020 4:19 pm
Forum: acorn atom and acorn system series
Topic: New AtoMMC board: V4
Replies: 57
Views: 1666

Re: New AtoMMC board: V4

I got Yoda ... okay it was 80DA but for a second I thought it said YODA! That is correct for ATMMC3A.rom So something else is wrong. I tested all the connections to IC24 from the CPU, IC23 and power and they were good. I tested all the connections to PL8 from the CPU, IC9 and power and they were goo...
by CommanderCoder
Fri Nov 13, 2020 10:41 am
Forum: acorn atom and acorn system series
Topic: New AtoMMC board: V4
Replies: 57
Views: 1666

Re: New AtoMMC board: V4

I'll do all those things and I'll check the continuity to socket 24 - might just aging tracks on the board.
by CommanderCoder
Fri Nov 13, 2020 8:05 am
Forum: acorn atom and acorn system series
Topic: New AtoMMC board: V4
Replies: 57
Views: 1666

Re: New AtoMMC board: V4

LK3 is closed. PL8 is on the keyboard side. Without the EPROM, the two test programs you posted both work fine; so the ATOMMC2 V4 board is working as expected. With the EPROM there is nothing and CTRL+BREAK causes general 'fuzzyness'. Here is a picture of the corruption and a short video(EDIT: video...
by CommanderCoder
Thu Nov 12, 2020 8:38 pm
Forum: acorn atom and acorn system series
Topic: New AtoMMC board: V4
Replies: 57
Views: 1666

Re: New AtoMMC board: V4

Got my V4 board and EPROM. It doesn't work (EPROM in Socket 24) so I'm wondering if I have dodgy port or socket, but that will have to wait until tomorrow. In the meantime I wondered if it is possible to type in a bit of code to check the EPROM contents when plugged into socket 21. The FP chip works...
by CommanderCoder
Fri Oct 23, 2020 8:01 am
Forum: acorn atom and acorn system series
Topic: New AtoMMC board: V4
Replies: 57
Views: 1666

Re: New AtoMMC board: V4

The plan I have is to add Colour and MMC so I can show it off to friends (they won't be impressed.. :roll: ) but I can see I'll need more RAM too. I assume the AtoMMC2 board will need the EPROM too - which I don't have. I'm not sure what to do about colour in combination with these other boards. I l...
by CommanderCoder
Thu Oct 22, 2020 8:53 am
Forum: acorn atom and acorn system series
Topic: New AtoMMC board: V4
Replies: 57
Views: 1666

Re: New AtoMMC board: V4

Me too. It will bring me a step closer to my perfect Atom.
by CommanderCoder
Sat Oct 10, 2020 4:11 pm
Forum: general
Topic: BBC : Back in Time for school
Replies: 1
Views: 191

BBC : Back in Time for school

Just thought you might like to see this; if you haven't already. Sorry for the facebook link. :evil:

https://www.facebook.com/BBCR2/videos/645101316206294
by CommanderCoder
Sun Oct 04, 2020 5:15 pm
Forum: 8-bit acorn hardware
Topic: RPi FDC
Replies: 99
Views: 3452

Re: RPi FDC

Thanks. After doing a bit of research, it might be possible to copy the ST disks using 'dd' on the raspberry pi. Anyway; back to the BBC, I was trying to copy my BBC disks using a Raspberry PI Zero W. It always gave me errors even on a disk that I knew was good. I switched to using a Raspberry Pi 3 ...
by CommanderCoder
Sun Sep 27, 2020 8:57 pm
Forum: 8-bit acorn hardware
Topic: RPi FDC
Replies: 99
Views: 3452

Re: RPi FDC

I've finally started using my RPi FDC with a Raspberry Pi Zero W and with a 5.25" BBC disc it seems to work but there are plenty of errors reading the discs. I assume that the discs are just old. I have also tried to connect the FDC to a 3.5" floppy drive but without much success. I'm not sure of th...
by CommanderCoder
Wed Sep 23, 2020 5:57 pm
Forum: acorn atom and acorn system series
Topic: Yet Another Acorn Atom Repair
Replies: 51
Views: 2221

Re: Yet Another Acorn Atom Repair

Switched around the chips and still the same result. I looked at the circuit diagram and because the ICs are used as buffers, for some reason I thought I'd check the continuity between pin 2 and 3 (the in and out of the buffers). They were connected. Turned over the motherboard and this is what I sa...
by CommanderCoder
Sun Sep 20, 2020 11:06 pm
Forum: for sale / freebies
Topic: For sale: RGBtoHDMI boards
Replies: 109
Views: 5524

Re: For sale: RGBtoHDMI boards

I'm interested in buying at least one RGBtoHDMI board for my newly repaired set of vintage computers: In particular to get colour on my Acorn Atom. So an Analogue board too. I have a EACA Video Genie (TRS80 Model I clone) which I think might be an interesting test for the board too. 1xAnalogue Board...
by CommanderCoder
Sat Sep 19, 2020 11:27 am
Forum: 8-bit acorn emulators
Topic: BeebEm Mac - Info
Replies: 200
Views: 19176

Re: BeebEm Mac - Info

It looks like I had the View set to 638x512 which is just wrong. I've set it to 640x512 now and I think Mode7 is looking good again. Have a look and see what you think. I've set it up so that the window is resizable but the view should stay the same aspect ratio within the window. Even at full scree...
by CommanderCoder
Sat Sep 19, 2020 11:04 am
Forum: acorn atom and acorn system series
Topic: Yet Another Acorn Atom Repair
Replies: 51
Views: 2221

Re: Yet Another Acorn Atom Repair

Had a bit of a panic last night. I put all the chips that roland sent to me back in the Atom, and the video was corrupted again. After some searching it looks like the 81LS95 tri-state buffers are interfering with the data bus. With either of them in IC2 or IC3 in any order, the image is just random...
by CommanderCoder
Thu Sep 17, 2020 9:15 pm
Forum: acorn atom and acorn system series
Topic: Yet Another Acorn Atom Repair
Replies: 51
Views: 2221

Re: Yet Another Acorn Atom Repair

I checked all the connections around the video circuit. All looked good. I improved the connection to my video phono so it is now a good connection. The picture came on and was really stable but odd colours. Then I had a sudden spark of inspiration. My TV has different picture modes for composite vi...
by CommanderCoder
Wed Sep 16, 2020 11:49 pm
Forum: acorn atom and acorn system series
Topic: Yet Another Acorn Atom Repair
Replies: 51
Views: 2221

Re: Yet Another Acorn Atom Repair

Moving the RAM around didn't help so I started the long task of checking every address and data line to the RAM from CPU or VDG. They were all okay. I then started checking the control lines specifically leading to IC51&IC52, or IC42/43 - these are the minimal RAM chips needed. The connections to IC...
by CommanderCoder
Mon Sep 14, 2020 7:31 pm
Forum: 8-bit acorn emulators
Topic: BeebEm Mac - Info
Replies: 200
Views: 19176

Re: BeebEm Mac - Info

I added repairing an old Acorn Atom to my list so BeebEm took a back seat for a while. I've just uploaded some fixes for COPY and PASTE of text from the original BeebEm. If think I fixed the problem with PASTE too. It's a bit of an odd fix. The original system would force a RETURN keypress. Instead ...

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