Search found 274 matches

by Ramtop
Mon Feb 08, 2021 3:41 pm
Forum: 8-bit acorn hardware
Topic: Beeb816 Revival
Replies: 79
Views: 3980

Re: Beeb816 Revival

That's an excellent and very useful summary! =D> From my experience with the Elk the whole system is fine at 3.3v levels, provided an NMOS 6502 or R65C02 is fitted. The ULA does not seem to have any problems at 3.3v. Also, from memory, PHI2 isn't connected on the Elk and PHI1 is only used for the RO...
by Ramtop
Sat Feb 06, 2021 2:03 pm
Forum: 8-bit acorn hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 565
Views: 65020

Re: Proposed: "The Ultimate Electron Upgrade"

The DECA board arrived a few days ago. In time honoured tradition the first thing I've done with it is flash some blinky LEDs. But this is Stardot, so I'm doing it using the T65 6502 core and a little machine code in the FPGA's block RAM :D The 6502 core and a bit of memory interface glue logic take...
by Ramtop
Fri Feb 05, 2021 11:39 pm
Forum: 8-bit acorn hardware
Topic: "Minus One" - 3 x cartridge Electron expansion
Replies: 99
Views: 7979

Re: "Minus One" - 3 x cartridge Electron expansion

I worded that last post really badly, apologies. :( The 3.3v for the JTAG programmer should be drawn from the same regulator as the CPLD, not the chip itself. No green light on the programmer means it can't detect that 3.3v supply on the Vref pin, suggesting the CPLD is unpowered or the JTAG Vref co...
by Ramtop
Fri Feb 05, 2021 12:29 am
Forum: 8-bit acorn hardware
Topic: "Minus One" - 3 x cartridge Electron expansion
Replies: 99
Views: 7979

Re: "Minus One" - 3 x cartridge Electron expansion

Check the reference voltage light on the programmer if it has one. The CPLD supplies a 3.3v signal to the programmer so if the light is off or red that means the signal is missing. The only reasons for that to happen are the CPLD not receiving power, or the JTAG connection being incorrect in some wa...
by Ramtop
Thu Jan 28, 2021 9:24 pm
Forum: 8-bit acorn hardware
Topic: Elk turbo board
Replies: 47
Views: 2513

Re: Elk turbo board

Any 6502 that works with the Electron will be fine, so provided it's a NMOS 6502A or a Rockwell 65C02 it should work.

The only time I had any kind of problems is with chips that were likely re-marked 1MHz parts and weren't stable when plugged directly into the elk.
by Ramtop
Thu Jan 28, 2021 4:18 pm
Forum: 8-bit acorn hardware
Topic: Elk turbo board
Replies: 47
Views: 2513

Re: Elk turbo board

I was keen to try my E2P with a Turbo board, because of course the host becomes a bottleneck and so speeding it up should have a noticeable effect. However, I found the effect was actually pretty small (this was using a Master Ram board). Perhaps I wasn't using a test scenario which put a big enoug...
by Ramtop
Thu Jan 28, 2021 4:04 pm
Forum: 8-bit acorn hardware
Topic: Elk turbo board
Replies: 47
Views: 2513

Re: Elk turbo board

walkerworks wrote:
Thu Jan 28, 2021 2:07 pm
It's a great project to get me started on these tiny components...thanks.
Excellent! I'm delighted it worked for you. :D

I do need to update the readme with more information about programming the CPLD, and clarify that it should be programmed with the OSTC installed and the elk powered up.
by Ramtop
Tue Jan 26, 2021 11:13 pm
Forum: 8-bit acorn hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 565
Views: 65020

Re: Proposed: "The Ultimate Electron Upgrade"

It's certainly powerful enough for that. Mine will, inevitably, end up sticking out of an Electron :D It'll make a much better dev platform than my current prototype ElkVGA board, which uses a 144-pin 10M08 FPGA and is quite severely crippled by that part's low number of I/Os, small amount of block ...
by Ramtop
Tue Jan 26, 2021 5:08 pm
Forum: 8-bit acorn hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 565
Views: 65020

Re: Proposed: "The Ultimate Electron Upgrade"

This may go down like a lead balloon but I noticed this: https://www.cnx-software.com/2021/01/26/arrow-deca-max-10-fpga-development-board-discount/ and it made me think of this project. Oooh, that's a very nice price! Thanks for posting it. Took the plunge and bought one of these from Arrow, £60 in...
by Ramtop
Mon Jan 25, 2021 11:00 pm
Forum: 8-bit acorn hardware
Topic: "Minus One" - 3 x cartridge Electron expansion
Replies: 99
Views: 7979

Re: "Minus One" - 3 x cartridge Electron expansion

Well done! And welcome to stardot. :D If it makes you feel a bit better, the shorted out CPLD almost certainly wasn't anything you did, I've had the same thing happen a small number of times with my ElkSD boards. Perfect soldering and a design that I've built hundreds of times, but as soon as the CP...
by Ramtop
Fri Jan 22, 2021 11:14 am
Forum: 8-bit acorn hardware
Topic: Electron ULA compatibility
Replies: 2
Views: 253

Re: Electron ULA compatibility

Cheers, Dave. :D

I'll swap the ULAs when I get some free time.
by Ramtop
Thu Jan 21, 2021 1:27 pm
Forum: 8-bit acorn hardware
Topic: Electron ULA compatibility
Replies: 2
Views: 253

Electron ULA compatibility

Hello all, Does anyone know if the issue 4 and issue 6 Electron ULAs are hardware compatible with each other? I've received an issue 6 board that someone has had a go at and butchered, to be frank. The PCB is scorched and warped from what looks like the attention of far too much hot air, all of the ...
by Ramtop
Sun Jan 17, 2021 1:48 pm
Forum: 8-bit acorn hardware
Topic: "Minus One" - 3 x cartridge Electron expansion
Replies: 99
Views: 7979

Re: "Minus One" - 3 x cartridge Electron expansion

I've had exactly that problem in the past on an early version of the OSTC and traced it back a bad output capacitor on the VRM causing huge swings in the CPLD vcc. The CPLD was just stable enough to report its ID but not to actually do anything else over JTAG.
by Ramtop
Sat Jan 09, 2021 8:44 pm
Forum: 8-bit acorn hardware
Topic: Elk turbo board
Replies: 47
Views: 2513

Re: Elk turbo board

Yes, that's spot on. It's a four layer board with the layers in that order.

I should have stated that explicitly, but it slipped my mind because I generally use JLCPCB and their ordering system just auto-detects everything from the Zip file generated by Diptrace.
by Ramtop
Fri Jan 08, 2021 12:15 am
Forum: general
Topic: Sophie Wilson awarded BCS Distinguished Fellowship Award
Replies: 8
Views: 400

Re: Sophie Wilson awarded BCS Distinguished Fellowship Award

Congrats to Sophie, well deserved! =D>
by Ramtop
Sat Jan 02, 2021 12:10 am
Forum: 8-bit acorn hardware
Topic: Elk turbo board
Replies: 47
Views: 2513

Re: Elk turbo board

I think the nice thing about the CPU socket way of fitting is that it's simple for someone who knows nothing about the Electron to do, so anyone who isn't confident doing it can just take the Electron m/b to pretty much any electronics repair shop and have them socket the CPU.
by Ramtop
Fri Jan 01, 2021 4:31 pm
Forum: 8-bit acorn hardware
Topic: Elk turbo board
Replies: 47
Views: 2513

Re: Elk turbo board

Ugh, there's always something!

I'll fix it now.
by Ramtop
Fri Jan 01, 2021 1:29 pm
Forum: 8-bit acorn hardware
Topic: Elk turbo board
Replies: 47
Views: 2513

Re: Elk turbo board

I'll be selling a slightly modified revision of the OSTC under the 'ElkExpress' name, for anyone not confident of building one. No firm date yet, however, as I'm very busy. EU/UK shipping is currently a bit of an unknown, neither side has produced any definitive guidlines that I can find. My underst...
by Ramtop
Fri Jan 01, 2021 12:20 pm
Forum: 8-bit acorn hardware
Topic: Elk turbo board
Replies: 47
Views: 2513

Re: Elk turbo board

It's taken rather longer than I'd hoped due to various events reducing the time I have for retro projects, but I'm happy to say the first version of the Electron Open Source Turbo Card is now public: https://github.com/ramtop-retro/ostc Unlike the prototypes, there are no fine-pitch components on th...
by Ramtop
Sat Dec 12, 2020 1:41 pm
Forum: 8-bit acorn hardware
Topic: Acorn Electron storing system
Replies: 11
Views: 723

Re: Acorn Electron storing system

*DOP U will remove write protection from a disk image.

If you find games that work from UEF file but not on the ElkSD, try *UNPLUG F and hit BREAK. That disables the Plus 1 ROM, which can cause issues with some games.
by Ramtop
Fri Nov 13, 2020 10:38 am
Forum: 8-bit acorn hardware
Topic: Help - Implementing Shadow RAM in CPLD
Replies: 154
Views: 6038

Re: Help - Implementing Shadow RAM in CPLD

I'll second that. There were some bizarre random issues with early revisions of my ElkSD boards on some Electrons that had me pulling my hair out, and the root cause was the XC9536XL it uses being thrown off by a noisy clock. Running the Electron's clocks through a Schmitt trigger buffer fixed the p...
by Ramtop
Sun Nov 08, 2020 8:56 pm
Forum: for sale / freebies
Topic: Electron SD Interface & SW Ram Expansion
Replies: 58
Views: 8219

Re: Electron SD Interface & SW Ram Expansion

Hi I was wondering if it'd be possible to use an adapter pcb to convert an ElkSD64 into the Plus One version, e.g. a pcb that slots into the ElkSD64 which fits in a cartridge slot? Sadly, no. The devices are quite different and there would be numerous problems involved. One example: the ElkSD64 des...
by Ramtop
Sun Nov 08, 2020 8:45 pm
Forum: for sale / freebies
Topic: Electron SD Interface & SW Ram Expansion
Replies: 58
Views: 8219

Re: Electron SD Interface & SW Ram Expansion

If that were to happen, would it not be possible to block the Electron booting from ROM in the same way you do with other physical roms when using a plus1. Press CTRL+Break then wait about a second and hit escape? Obviously I'm not willing to test out that question given the card just arrived and I...
by Ramtop
Wed Nov 04, 2020 2:38 pm
Forum: 8-bit acorn hardware
Topic: ElkSD Plus 1 Card?
Replies: 5
Views: 323

Re: ElkSD Plus 1 Card?

the supplier only seems to be contactable via ebay messaging. I hang out here as well :D As I said via Ebay, it's a problem with the card you're using. A few of the really cheap Chinese ones don't implement SPI mode correctly, and the ElkSD uses SPI to communicate with the card. It's not an age or ...
by Ramtop
Sun Nov 01, 2020 12:15 pm
Forum: for sale / freebies
Topic: Electron SD Interface & SW Ram Expansion
Replies: 58
Views: 8219

Re: Electron SD Interface & SW Ram Expansion

Out of interest, IF a card is bricked due to a bad flash update or uploading a game into the ROM rather than RAM and getting stuck with it auto-booting. Is there any way recover from this even if it requires some extra hardware to reflash things directly? I've no idea about the hardware used in thi...
by Ramtop
Thu Oct 29, 2020 9:14 pm
Forum: the complete BBC games archive
Topic: The complete Electron games archive
Replies: 23
Views: 2011

Re: The complete Electron games archive

Oh, yes, using main memory as a buffer will certainly work. I was thinking more along the lines of people trying to load a ROM image directly into bank 12 with *SRLOAD. No way to make that happen. I wish I'd been able to implement a split ROM/RAM bank for MMFS in the 64, as is the case with the ElkS...
by Ramtop
Thu Oct 29, 2020 7:29 pm
Forum: the complete BBC games archive
Topic: The complete Electron games archive
Replies: 23
Views: 2011

Re: The complete Electron games archive

If Gary wants to use the photo there is no problem for it... Your photographic skills are certainly better than mine! :D To give a definative answer on using bank 12 for ROM images for anyone who's interested: no it's not possible. The ElkSD64 uses the 'Z' version of MMFS which copies itself from R...
by Ramtop
Tue Oct 27, 2020 1:43 pm
Forum: 8-bit acorn hardware
Topic: 65816 speed grades
Replies: 6
Views: 300

Re: 65816 speed grades

Mouser sells brand new DIP 65C816-14s:
https://www.mouser.co.uk/ProductDetail/ ... JD3DWt8%3D
by Ramtop
Wed Oct 21, 2020 8:03 pm
Forum: 8-bit acorn hardware
Topic: Hard Gold or Enig Finish for Edge Connector Fingers
Replies: 11
Views: 424

Re: Hard Gold or Enig Finish for Edge Connector Fingers

Can't comment on other fabs, but JLC strip everything but the copper/gold finish from the contacts area when you select gold fingers. I found that out by accidentally uploading the wrong gerbers for a board, where I hadn't removed the solder mask and actually had left silkscreen over the top of the ...
by Ramtop
Wed Oct 21, 2020 6:26 pm
Forum: 8-bit acorn software: other
Topic: MMFS Version 2
Replies: 498
Views: 11833

Re: SD card without the MMB file (aka MMFS2)

I don't think it's been updated at all since then. I implemented MMFS2 as an option on my original ElkSD-Plus 1 catridge since I'm not much of a fan of the beeb.mmb file approach, but it seemed to just die so I got cold feet and went back to the standard build of MMFS for rev 2 of the cartidge.

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