Search found 1121 matches

by cmorley
Tue Jan 21, 2020 5:44 pm
Forum: hardware
Topic: Chip extraction tool...
Replies: 2
Views: 100

Re: Cip extraction tool...

I have an EX-2. It will fit on the CPU and VIAs but the tape relay is in the way for the 6845 on a model B.
by cmorley
Tue Jan 21, 2020 3:19 pm
Forum: introduce yourself
Topic: Hello from exotic Coventry UK
Replies: 13
Views: 291

Re: Hello from exotic Coventry UK

Do people think its worth keeping it as close to Model A spec as possible, or does the fact its already partially upgraded effectively negate its Model A-ness? I'd be interested in peoples thoughts...? Upgrading an A to a B by fitting all the parts was a legitimate thing to do back in the day. A's ...
by cmorley
Tue Jan 21, 2020 8:56 am
Forum: emulators
Topic: Arculator v2.0 released!
Replies: 27
Views: 3563

Re: Arculator v2.0 released!

I fired it up at the weekend and it is a massive step, thanks Sarah. I saw the ZIDEFS ROM is in the Windows distribution so I copied my 4GB DOM A3000 image to the hard disk and mounted it... the dialog only goes up to 504MB but I tried anyway and it works with my 4x 500MB ZIDEFS drives - so I assume...
by cmorley
Mon Jan 20, 2020 6:34 pm
Forum: for sale / freebies
Topic: For Sale: 27C400 EPROM emulators (beta) issue D
Replies: 3
Views: 137

Re: For Sale: 27C400 EPROM emulators (beta) issue D

1024MAK wrote:
Mon Jan 20, 2020 6:30 pm
Yep, definitely still interested :D

Mark
I'll bring some to ABUG.
by cmorley
Mon Jan 20, 2020 6:15 pm
Forum: introduce yourself
Topic: Hello from exotic Coventry UK
Replies: 13
Views: 291

Re: Hello from exotic Coventry UK

Welcome! :D
by cmorley
Mon Jan 20, 2020 11:19 am
Forum: other vintage computer hardware, software and games
Topic: 27C400/800/160/320 emulator/ROM switcher
Replies: 28
Views: 1948

Re: 27C400/800/160/320 emulator/ROM switcher

I have checked the A3010 & A3020 schematics. They both use 27C800 (27C160 but A21 not used) pinout so these modules should work. Probably worth a test at ABUG... not sure how useful OS switching is on an Archie but it is worth confirming it works. I think you can rebuild RiscOS with other files/modu...
by cmorley
Mon Jan 20, 2020 11:16 am
Forum: for sale / freebies
Topic: For Sale: 27C400 EPROM emulators (beta) issue D
Replies: 3
Views: 137

For Sale: 27C400 EPROM emulators (beta) issue D

Anyone following my EPROM emulator thread might be please to know that I am ready to sell some of the beta units. The module emulates a 27C400 (also 27C200/27C800/27C160) which are 16 bit JEDEC pinout EPROMs. It also correctly handles the /BYTE pin for 8-bit operation :D Program via USB - do NOT ins...
by cmorley
Sun Jan 19, 2020 12:40 pm
Forum: hardware
Topic: Open source A3020 RAM
Replies: 44
Views: 2113

Re: Open source A3020 RAM

Thanks Mark! There isn't a lot of room but there is enough it seems... the boards are much harder to install when all the pins are populated - and I left of as many as I could. So I'd say it is a shield off job for all but the most brave soles. Next weekend at ABUG we'll try a fit & electrical test ...
by cmorley
Fri Jan 17, 2020 9:24 am
Forum: off-topic
Topic: Which soldering iron?
Replies: 19
Views: 412

Re: Which soldering iron?

Any temperature controlled iron is a step up. You don't need to pay a lot & I wouldn't recommend doing so unless it is going to get frequent use. One trick for dealing with ground planes is two soldering irons... so when you get a new station keep the old one for those stubborn connectors. You can r...
by cmorley
Thu Jan 16, 2020 2:37 pm
Forum: hardware
Topic: BBC sound to CUB DIN
Replies: 2
Views: 192

Re: BBC sound to CUB DIN

I copied what tricky did - loop the speaker through a jack plug at the back (3.5mm mono in my case). I mounted the 3.5mm socket between the 'reset' hole and the ECONET hole. Jack in sound -> TV Jack unplugged sound -> speaker I added a 3.5mm mono plug to my SCART lead but a separate lead to a DIN pl...
by cmorley
Mon Jan 13, 2020 7:29 pm
Forum: upcoming and recent events & exhibitions
Topic: ABUG SOUTH 24 to 26 January 2020: NOW FULL
Replies: 149
Views: 5246

Re: ABUG SOUTH 24 to 26 January 2020: NOW FULL (but taking names for reserve list)

I have a dozen SMD antistatic foam boxes chips came in I don't need. Anyone want some I can bring them to the ABUG?
by cmorley
Mon Jan 13, 2020 7:01 pm
Forum: hardware
Topic: Open source A3020 RAM
Replies: 44
Views: 2113

Re: Open source A3020 RAM

Would a solution based on the Si5351 be a possible? I imagine so. Put it and a 25MHz crystal on a small 8 or 14 pin DIP footprint PCB & program with an AT-Tiny USB adapter or something? You'd need a 3v3 reg and a 5V buffer on the output for an archie... That might be a handy widget Ian. Were you th...
by cmorley
Mon Jan 13, 2020 5:47 pm
Forum: hardware
Topic: Open source A3020 RAM
Replies: 44
Views: 2113

Re: Open source A3020 RAM

This thread is to wordy...

RAM in an A4000:
Photo0885.jpg
No oscillators so clock from an FPGA:
Photo0888.jpg
Bodge a buffer onto a SOIC breakout adapter:
Photo0886.jpg
Result!
Photo0883.jpg
by cmorley
Mon Jan 13, 2020 5:39 pm
Forum: for sale / freebies
Topic: For Sale: A3020/A4000 & A5000 overclockable RAM
Replies: 4
Views: 353

For Sale: A3020/A4000 & A5000 overclockable RAM

Now the open source RAM project is tested working I am going to be assembling some. If you want to overclock your machine they seem to be a good prospect. A3020 RAM thread A5000 RAM thread Since the original backer of the project is buying a bulk order I can offer the cards for £30 as there is an ec...
by cmorley
Mon Jan 13, 2020 3:20 pm
Forum: hardware
Topic: Open source A3020 RAM
Replies: 44
Views: 2113

Re: Open source A3020 RAM

72MHz - I wonder if you could just link the video oscillator over to the CPU clock input?! I looked on mouser and digikey and the DIP type oscillators are not easy to buy anymore.
by cmorley
Mon Jan 13, 2020 12:39 pm
Forum: hardware
Topic: Open source A3020 RAM
Replies: 44
Views: 2113

Re: Open source A3020 RAM

I've done some more testing and looked at some of the RAM signals on the scope. It looks good. The system isn't stable at 75MHz oscillator but I'm not sure the RAM is the limit... the RAM test at 75 works perfectly every time. It might be the limit of this ARM250 or it might be the quality of my gen...
by cmorley
Mon Jan 13, 2020 8:35 am
Forum: hardware
Topic: New Raspberry Pi to 1MHz bus interface
Replies: 61
Views: 1710

Re: New Raspberry Pi to 1MHz bus interface

I've seen a table that indicates a RPi Zero consumes about 160mA, so what's the thoughts about pulling about 320mA from the 5 x 5v pins on the tube port to feed the 2 x level shifters and associated RPis? 160mA sounds like the idle current, the internet suggests... more like ~240mA under load. The ...
by cmorley
Sun Jan 12, 2020 9:42 pm
Forum: hardware
Topic: Open source A3020 RAM
Replies: 44
Views: 2113

Re: Open source A3020 RAM

I tried an overclock today on an A4000. I don't have a range of crystal oscillators so I hooked up an FPGA to use the PLL. I soldered a buffer onto a SOIC breakout board to get a 5V CMOS output and plugged that in X100. It isn't ideal but it will do for testing and I can adjust the clock speed easil...
by cmorley
Sat Jan 11, 2020 3:54 pm
Forum: hardware
Topic: Open source A3020 RAM
Replies: 44
Views: 2113

Re: Open source A3020 RAM

Sure take a look. They aren't fun to remove at the moment because of the friction of all the pins in the ZIP sockets. You can get the exact dimension from the gerbers.... viewmate will export DXF from Gerbers for example. The hole is there to miss the links on the motherboard - you'll need to work a...
by cmorley
Sat Jan 11, 2020 3:51 pm
Forum: other vintage computer hardware, software and games
Topic: 27C400/800/160/320 emulator/ROM switcher
Replies: 28
Views: 1948

Re: 27C400/800/160/320 emulator/ROM switcher

The software is now on v0.5 and I've sent links to all the testers. The Intel HEX parser fit :) I've done some cosmetic tidy up and behind the scenes tidy up so short of bug reports and cosmetic suggestions this is pretty much ready to go. I assembled 10 modules and am just waiting on some 1uF caps ...
by cmorley
Fri Jan 10, 2020 12:53 pm
Forum: hardware
Topic: New Raspberry Pi to 1MHz bus interface
Replies: 61
Views: 1710

Re: New Raspberry Pi to 1MHz bus interface

MLCC are typically microphonic so that's one reason why they should be avoided for audio circuits.
by cmorley
Wed Jan 08, 2020 11:58 am
Forum: upcoming and recent events & exhibitions
Topic: RISC OS South West Show Saturday 22nd February 2020
Replies: 4
Views: 227

Re: RISC OS South West Show Saturday 22nd February 2020

I could come along. Bristol isn't rally all that far from Oxford...

I'd probably bring a B perhaps with my Bad Apple demo. Or i could bring a Master for some variety if you're bringing Bs Rob?
by cmorley
Tue Jan 07, 2020 7:01 am
Forum: hardware
Topic: Open source A3020 RAM
Replies: 44
Views: 2113

Re: Open source A3020 RAM

Would you like me to ferret around in the attic and try to find one of my A3020s to bring along to ABUG this month? I might bring both (if I can find them) as they both might have original batteries inside which I really ought to have removed years ago. Well if you can that might be handy. The boar...
by cmorley
Tue Jan 07, 2020 6:50 am
Forum: introduce yourself
Topic: Hi from Perth, Australia
Replies: 10
Views: 219

Re: Hi from Perth, Australia

Welcome! :)
by cmorley
Mon Jan 06, 2020 8:53 pm
Forum: off-topic
Topic: PayPal fees on tax collected by eBay
Replies: 13
Views: 621

Re: PayPal fees on tax collected by eBay

eBay has been collecting taxes for governments for a long time for example in Australia. The seller previously had nothing to do with this - it was between the buyer, ebay & government. This is about shifting PP fees for this tax collection onto the sellers through creative accounting. It's the fees...
by cmorley
Sun Jan 05, 2020 2:34 pm
Forum: off-topic
Topic: PayPal fees on tax collected by eBay
Replies: 13
Views: 621

Re: PayPal fees on tax collected by eBay

They started doing this on US sales now too. Yey! More fees.
by cmorley
Sun Jan 05, 2020 12:55 pm
Forum: hardware
Topic: Open source A5000 RAM
Replies: 18
Views: 1284

Re: Open source A5000 RAM

OK testing has gone well & they seem fine. Only question left is how well the overclock. I'm not sure if Steve3000 is going to have a go overclocking the A5000 or not. I will make one batch of these by order for stardotters. They won't be an ongoing product from me. Please don't respond to this thre...
by cmorley
Sun Jan 05, 2020 12:51 pm
Forum: hardware
Topic: Open source A3020 RAM
Replies: 44
Views: 2113

Re: Open source A3020 RAM

OK testing has gone well & they seem fine. Only question left is how well the overclock. I will try to answer this on an A4000 before the January ABUG. I will make one batch of these by order for stardotters. They won't be an ongoing product from me. Please don't respond to this thread I will post a...