stardot.org.uk

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...

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...

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...

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...

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.

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...

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.

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.

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 ...

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...

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...

Cheers, Dave.

I'll swap the ULAs when I get some free time.

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 ...

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.

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.

Congrats to Sophie, well deserved!

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.

Ugh, there's always something!

I'll fix it now.

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...

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...

*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.

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...

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...

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...

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 ...

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...

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...

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...

Mouser sells brand new DIP 65C816-14s:
https://www.mouser.co.uk/ProductDetail/ ... JD3DWt8%3D

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 ...

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.