Search found 581 matches

by myelin
Mon Feb 25, 2019 12:19 am
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

What about making use of the existing RGBS signals from the ULA to the DIN socket (as Daniel suggested). In VGA mode, the Sync signal would be a composite sync with a line frequency of 31.250 KHz. You would then need a small external dongle with a sync seperator (e.g. an LM1881) and a DSUB connecto...
by myelin
Sun Feb 24, 2019 1:47 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

Some thoughts on the VGA output... It looks like Hoglet is using the Papilio Classic Computing Shield, which uses resistors (3.9k, 2k, 1k, 510R) from four 3.3V IOs on the XC6SLX9 to generate each of the RED, GREEN, and BLUE signals, and drives VSYNC and HSYNC via 82.5R resistors. Anyone have any ide...
by myelin
Sun Feb 24, 2019 7:03 am
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

Fast read in QPI mode page 41. I see now... not all QSPI flash chips are created equal. I'd also missed that the mode bits counted as dummy cycles. - IS25LP016D can read a command byte in two cycles via QPI, so 16 cycles for the first read and 14 for future reads in AX mode. - MX25L3233F always tak...
by myelin
Sun Feb 24, 2019 12:47 am
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

You need a quad SPI part like IS25LP016D for example. In quad mode it only takes ~18 cycles. Actual cycle count depends on the number of NOPs which depends on the clock... the datasheet is pretty good. Can you point me at the details for how to do that? The fastest operation I can see in the datash...
by myelin
Sat Feb 23, 2019 8:38 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

A QSPI NOR Flash chip might serve your purpose. It's in the order of 20 clocks at 100+ MHz to get a byte so ~200ns Can you point me at a part that can do this? All the ones I've looked at take more like 40 clocks... not a dealbreaker as we can just treat it as slow memory and run at 1MHz, but if th...
by myelin
Sat Feb 23, 2019 8:27 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

Update:

- Added all ULA pins, from the Electron schematic in the EAUG.
by myelin
Sat Feb 23, 2019 11:00 am
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

A QSPI NOR Flash chip might serve your purpose. It's in the order of 20 clocks at 100+ MHz to get a byte so ~200ns This is really clever. I still like the idea of having a big SDRAM just in case, but QSPI flash is cheaper and easier to route on the PCB (and saves FPGA IOs), and given that we're the...
by myelin
Sat Feb 23, 2019 8:14 am
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

What would we actually use the SDRAM for. Extra sideways RAM? I can't see needing to access FLASH and SDRAM at the same time. Have you given any thought to a suitable connector for VGA video out? Yes, sideways RAM, I suppose. I figured if it’ll fit, it wouldn’t hurt to put in some more memory. I ha...
by myelin
Sat Feb 23, 2019 7:58 am
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

Yes! I hope it all works in the end :D Another question for Dave: the memory chips I’m looking at have a 16 bit bus (the flash chip has a byte/word select, and the SDRAM is 16 bit only but we can just wire up half of it if we only want 8 )... do you think it would be worth going to the trouble of wi...
by myelin
Sat Feb 23, 2019 7:17 am
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

A couple of updates...

- I've added one of the 8MB flash chips I used on the Arcflash board, as an optional component in case we want/need it. I'm also planning on adding a 16MB SDRAM chip.

- I've added the 3.3V regulator.

pcb-front.png
by myelin
Fri Feb 22, 2019 7:00 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

You just want the one :roll: I can send you a working Electron with the ULA socket removed and Pin Sockets in it place. You can then just have pins from your board to plug into the Elk. I'm away for a week, from tomorrow. I can get it sent off to you when I'm back. Thanks so much Dave! Maybe hold o...
by myelin
Fri Feb 22, 2019 5:54 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

Indeed... I believe the compact version (the one we’d be using) of the 10M08 has 32kB of user flash. The user guide doesn’t explain super well, but I think that’s what we get.

I’m also hoping to fit a flash chip on there, in case this turns out to be incorrect, though :)
by myelin
Fri Feb 22, 2019 3:53 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

Here's a link that shows what the adaptor board looks like and here's a link to a post where I attached a DXF of the adaptor board. I have 1 or 2 left. Phill, I could send you one if it would be useful? It would be a week on Monday when I could get it ready, as I'm away for a week from tomorrow. Yo...
by myelin
Fri Feb 22, 2019 7:22 am
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

All right... let's have a go at making a PCB for the ULA replacement; it looks like it might not be that hard to get a PCB together (not to say that getting it to work will be easy, but if this results in a few mostly working prototype boards that people can play with, I think that will count as a s...
by myelin
Thu Feb 21, 2019 3:08 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

As well as emulating an entire Electron, there is a "big mess of wires" prototype of the ULA replacement (also using a Papilio Duo) that plugs into a real Elk ULA socket (using an adapter board) that Dave H made: IMG_0579.JPG More photo's here: https://stardot.org.uk/forums/viewtopic.php?p=149156#p...
by myelin
Thu Feb 21, 2019 3:03 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

This idea might be of interest - break the rules, ignore the most interior of the pads (except where you mustn't), and you can do wonders even with only a single layer: If it's the 169pin package there a good chance of making it work as you can bring over 90 tracks out on one layer - should be more...
by myelin
Wed Feb 20, 2019 9:04 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

Oh wow! I should have reread the whole thread... I had no idea this had ever run connected to an Elk!
by myelin
Wed Feb 20, 2019 8:34 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

To answer mr-macrisc's question -- no, there is no circuit. What we have right now is a ton of FPGA work from Hoglet, that runs on a Papilio Duo board and emulates an entire Electron. If I were doing the hardware design for this, I would probably go for the 10M08 from Intel; it just needs a single 3...
by myelin
Wed Feb 20, 2019 12:45 am
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

In this case though the prototype did do a fair amount and belive was working reasonably well. So although it went off boil with a re-vist as dave was going to ask may produce something. I believe the state of things is that Hoglet has quite a complete FPGA implementation of the entire Electron, bu...
by myelin
Tue Feb 19, 2019 8:28 pm
Forum: hardware
Topic: Proposed: "The Ultimate Electron Upgrade"
Replies: 284
Views: 18760

Re: Proposed: "The Ultimate Electron Upgrade"

Replace broken ones will possibly only be a seller when one brakes (but only if cheaper than finding a replacement ULA or electron) if it isn't cheaper then the basic replacement ULA isn't a viable option to sell at moment. Value added performance option gives a reason to buy now and not when machi...
by myelin
Sat Feb 16, 2019 12:05 pm
Forum: general
Topic: Today I received.....
Replies: 5058
Views: 369403

Re: Today I received.....

Yep, it’s all about whether you’ve burned the fuse bits or not. Definitely worth trying to read the chip out though! Of course if you have the VHDL or Verilog source, it’ll be much easier to do a circuit design...much less reverse engineering required.
by myelin
Thu Feb 14, 2019 6:27 pm
Forum: general
Topic: Today I received.....
Replies: 5058
Views: 369403

Re: Today I received.....

Received yesterday: IMG_3163-2.jpgIMG_3163.jpgIMG_3164.jpg I'm preparing a very special Electron for John. I wonder if I'll have any luck asking my ex partner, Dave Prosser, if he has the FPGA script . . . . [-o< :? Dave H :D Ooh... if you do manage to get it, I’d be Interested to help with the PCB...
by myelin
Thu Feb 14, 2019 5:34 am
Forum: hardware
Topic: "Arcflash" A3000/A3xx/A4xx/A5xx/A5000 in-system programmable ROM -- any interest?
Replies: 94
Views: 3308

Re: "Arcflash" A3000/A3xx/A4xx/A5xx/A5000 in-system programmable ROM -- any interest?

More progress... I have 1MB, 2MB, and 4MB flash banks working and selectable through the bootloader. Not enough room in the CPLD to also do 512kB banks, but with 16MB of flash that doesn’t matter so much. I have my test setup running with four 1MB banks (bootloader, A1 test rom, Arthur 1.20, RO2.01)...
by myelin
Thu Feb 14, 2019 12:20 am
Forum: hardware
Topic: RISC OS 3.20 ROM's?
Replies: 128
Views: 8622

Re: RISC OS 3.20 ROM's?

I was using RedSquirrel to test. I assume you've tried resetting the BIOS? Red just means something hardware related failed in POST, take a look at the POST process for more info - the colour sequence will help pinpoint which test is failing. Aha! I was just too quick to call it quits. I just got i...
by myelin
Tue Feb 12, 2019 1:46 pm
Forum: hardware
Topic: RISC OS 3.20 ROM's?
Replies: 128
Views: 8622

Re: RISC OS 3.20 ROM's?

I've managed to build RO320 using the instructions in the OP, under RO 3.11 on Arculator. Ran into some issues with filenames getting truncated upon unarchiving with SparkPlug, but the build seemed to proceed OK after fixing those, and I get a 4MB RO320 file. Trying to run the new ROM, however, I ge...
by myelin
Tue Feb 12, 2019 7:05 am
Forum: hardware
Topic: "Arcflash" A3000/A3xx/A4xx/A5xx/A5000 in-system programmable ROM -- any interest?
Replies: 94
Views: 3308

Re: "Arcflash" A3000/A3xx/A4xx/A5xx/A5000 in-system programmable ROM -- any interest?

The bootloader works! I can now turn on my A3000, see the bootloader come up and initialize the keyboard and display, hit 1-7 to select a 2MB flash bank, hit RESET, and be in my selected OS :D This has taken forever — such a relief to see it finally working! Heading to bed now... will post a video l...
by myelin
Mon Feb 11, 2019 11:17 pm
Forum: for sale / freebies
Topic: Electron MicroSD Card Interfaces (now Mk2)
Replies: 83
Views: 2339

Re: Electron MicroSD Card Interfaces

You read my mind :D I've already designed a board that can use a 39SF010, but it's more of a dev board for messing about with stuff. It takes various flash parts, 62256 SRAMs, 27128/27256 eproms, etc, and has a bunch of I/O pins. Right now I'm in the process of scaling that down to be V2.0 of the M...
by myelin
Mon Feb 11, 2019 10:47 pm
Forum: for sale / freebies
Topic: Electron MicroSD Card Interfaces (now Mk2)
Replies: 83
Views: 2339

Re: Electron MicroSD Card Interfaces

Thanks, myelin. I just thought there was a need for a lower priced memory card board for the Elk, when I bought mine the only card interface I could find was the GoSDC, which is a fine product but not inexpensive. Hoglet's work on the Electron printer port MMFS version has made it possible to do a ...
by myelin
Mon Feb 11, 2019 7:53 pm
Forum: hardware
Topic: New hardware suggestion - Pi econet server
Replies: 51
Views: 2212

Re: New hardware suggestion - Pi econet server

Pretty much all the projects described in this thread (definitely mine and flynnjs's) also produce a clock. I'm sure a Pi could do it too.
by myelin
Mon Feb 11, 2019 6:45 pm
Forum: for sale / freebies
Topic: Electron MicroSD Card Interfaces (now Mk2)
Replies: 83
Views: 2339

Re: Electron MicroSD Card Interfaces

Nice! Excellent for all the folks out there without a Plus 1, and it's great to see a new Elk hardware designer here -- welcome!