Elksd-plus1 Interface

[jdavis6809]

hello,

Not much information on this site about this interface ? (no hardware / software detail)

I have interface works ok, but it is slow and the menu listing is messed up and elite does not work most likely wrong file

Any plans to improve this ?

Any planes to open source this so others can improve it ?


john uk

[Ramtop]

Well, I can possibly help you as I designed the ElkSD-Plus1!

Can you elaborate on the problems you're having? 'messed up' doesn't really give me much to go on.

As for the speed, I've sold about 40 of these and I think you're only the second person to mention it as an issue. The ElkSD can fill the Electron's useable memory in less than 5 seconds, which I always thought was quite acceptable performance. However, there is an improved revision 2 card in the works along with a new higher-end model that will be *very* fast, but correspondingly expensive.

[0xC0DE]

As for the speed, I've sold about 40 of these and I think you're only the second person to mention it as an issue.

I may be that other person
But I'm not talking about normal use. I need the speed for streaming data, e.g. in my Bad Apple demo the ElkSD read speed is the limiting factor.
Make no mistake, I'm very happy with Ramtop's products.

[Ramtop]

I think you were, yes

And I agree about special use cases like Bad Apple; performance that's fine for loading 20-something KB of game code isn't necessarily up to streaming data. The dilemma I have is just how many people would be willing to pay extra for higher speed? Not many, I think.

The ElkSD-P1 has a bit of spare logic capacity in its CPLD chip, so on the Rev2 board I've made some hardware changes that mean I can use the capacity for a faster SD card interface. It won't be warp speed, but should be pleasantly quicker and, most importantly, only ups the build cost by 50p or so. This is some way off, though, as I've only just ordered the first prototype PCBs for the Rev 2.

Right now I also have a brand new SD interface operating as part of an FPGA based Elk expansion (not quite ready to talk about that board yet, it's still a bit raw). It uses a full hardware SPI controller and operates at about 50K/sec reads (so around 8x faster than the ElkSD-P1) and 30K/sec writes, which has to be one of the fastest MMFS implementations so far. I'm toying with squishing that interface down into a Plus 1 cartridge.

It won't be cheap and I'd probably only sell 3 of them, but I may still do it just for giggles

[jdavis6809]

hello ramtop,

I did replay on ebay about this issue, but you responded as to say this this a known issue

the menu issue is the name of the game listed is not the game played ie menu messed up

the beeb.mmb file used was elkbig from you website

other functions useful snapshot of a game level

the retroclinic sd works far faster with full beeb.mmb file (which I have as well)

anybody used a retroclinic sd on a elk with an ap5 interface ? (userport)

regards

john uk

[Ramtop]

Ah, yes. I remember now!

I did post a tidied up version of that menu not long after our conversation that fixed some issues. But the menu's author, Ray Harper, has produced a new and much improved version that you can find here: http://rayharper.co.uk/stardot/Stardot.html

The ElkSD is slower than a user port SD reader, no doubt about that. But given almost all the feedback I've had on it has been very positive, I don't think most buyers regard that as a problem - particularly since very few will be able to directly compare the two.

In the end it mostly comes down to money. I could have made the ElkSD-P1 very fast indeed, but at the cost of adding £20 to the price. My opinion at the time of doing the design was very firmly that an SD card interface should not cost more than the computer it's being connected to. As Elks were (and sometimes still are) fetching less than £50 in good working order, that put a fairly tight cap on the build cost.

But I will be doing a faster version, mostly because I'm a compulsive tinkerer who can't leave well alone

[stuslayer]

Hi Gary,

Sorry to resurrect an older thread, but I was wondering when you might have the ElkSD Plus1 available again (if at all)? I've already got your excellent ElkSD MkII, and I now have a second Elk with Plus 1 that would love to have one of these bad boys in it's slot (ooer!). Any plans to do another run of these?

Stu

[Ramtop]

Yep. More should be available shortly, possibly as soon as next week. Can't say a date for sure yet as the next batch is the first run of the new revision 2 boards, which are quite a bit different from the old rev 1 model. I'm still testing the new ROM that's required for the rev 2 hardware, but it's looking pretty solid so a release next week is what I'm aiming for.

I'll update the thread in the For Sale forum when I'm ready to take orders.

[stuslayer]

Yep. More should be available shortly, possibly as soon as next week. Can't say a date for sure yet as the next batch is the first run of the new revision 2 boards, which are quite a bit different from the old rev 1 model. I'm still testing the new ROM that's required for the rev 2 hardware, but it's looking pretty solid so a release next week is what I'm aiming for.

I'll update the thread in the For Sale forum when I'm ready to take orders.

Brill!! When they're available, please put me down for one

[mr-macrisc]

Yep. More should be available shortly, possibly as soon as next week. Can't say a date for sure yet as the next batch is the first run of the new revision 2 boards, which are quite a bit different from the old rev 1 model. I'm still testing the new ROM that's required for the rev 2 hardware, but it's looking pretty solid so a release next week is what I'm aiming for.

I'll update the thread in the For Sale forum when I'm ready to take orders.

Did we get any info on the fast version???

[Ramtop]

I should have remembered to post something about this, sorry!

The new, faster revision 2 cartridges are finished and presently on sale via Ebay. I haven't made them available at a discount in the For Sale forum yet because sales on Ebay have been far higher than I expected - the rev 2 is proving to be really popular - and it's been a struggle keeping up. Trying to up the number I'm building, but this is a bit hampered because of the present heat wave here in the UK which means my loft workshop, where I do the building, is reaching 34C during the day. Scotsmen aren't made to cope with that

Hopefully I'll have some cartridges available here late next week.

I'm also interested in any comments on something I'm working on now, basically a version of the ElkSD-Plus1 rev2 that works with a Master. The rev 2 PCB was designed to work on both the Plus1 and Master, but it turned out a dual-system card wasn't possible because the CPLD has insufficient capacity for the extra logic required. So there needs to be a separate Master version. This is now working and seems good and stable.

The uncertainty is price; it's going to cost a little over £40, which is a fair bit more than a standard user-port SD interface. The cartridge offers advantages - easier installation and access, faster write speeds (read is about the same), on-board SRAM so MMFS uses none of the Master's memory for slightly better compatibility with anything that needs PAGE at E00 and all 4 SW ram banks, 16K of extra sideways RAM, and MMFS can be updated via software.

But I'm genuinely interested in everyone's view if that's enough to justify the higher price.

[mr-macrisc]

Yeah I think it can justify price...

I like my wee micro SD user port device but I’d much rather a cartridge with really easy SD access to allow me to quickly grab and add files too. Lifting a master up and extracting the micro SD can be a pain in the ass.

Ok so some may have gotek or beeb scsi or similar already but I just really like the cartridge look and format and easy access to the SD.. no need to install in a case or make up bespoke plates for it or work out where to hide wires. It’s all done and ready to use. Also a lot of people probs underutilise the cartridge slot (yeah maybe have some rom cartridges or something but not much else). Where as people probs have things they can/could use ports for but how many are fully utilising the slots and do so all the time?

Yeah ok elk it helps other solutions aren’t as available but tbh I reckon the fact it’s a superb use of a cartridge slot of a big part of it that master users will also love

[Ramtop]

I agree, unsurprisingly

Decided to actually push ahead with this. The prototype is working very well and the outlay involved is low as it's identical hardware to the ElkSD-Plus1; if the 'MasterSD' flops I can just convert them to ElkSDs.

[mr-macrisc]

Did you not say earlier there would be a faster elk version then an all singing all dancing super fast version?

Is that still plan or is one on sale now the super fast?

[Ramtop]

I may have been guilty of being over optimistic here.

The 'super-fast' design was a reference to the high-speed SPI controller which is used to handle the SD cards on the FPGA-based ElkVGA prototype. That tops out at 53K/sec read and 41K/sec writes on the Elk, which puts reads around 9x faster than the ElkSD64 or ElkSD-Plus1 rev 1.

I had intended to port this controller over to the ElkSD-Plus1 rev 2 hardware, but two problems became clear quite quickly. The ElkSDs use a simple CPLD chip rather than the much more capable and expensive FPGA on the ElkVGA, and the CPLD just didn't have enough room. So the SPI controller had to be pared down a bit, which reduced performance. Additionally, the MMFS driver I wrote for the ElkVGA got much of its speed by taking sort-cuts that meant it would only work on that hardware; with the ElkSDs I really needed a driver that would safely work on multiple similar devices, to keep the job of updating it manageable.

So the present situation is this: the ElkSD64 retains the old bit-bang SPI interface which manages about 5.5K read and 7K writes. This will stay as-is indefinitely, because there's no way to speed the hardware up without an increase in cost. The ElkSD64 is intended for loading old games, so the speed is entirely fine in my view and putting the price up wouldn't be justified.

The ElkSD-Plus1 rev 2 uses the cut-down SPI controller which gives 25k/sec read and write using a 'safe' MMFS driver that doesn't take any liberties.

The upcoming 'MasterSD' (the name may change) is essentially an ElkSD-P1 rev 2 tweaked to run on the Master. It uses the same SPI controller but clocked more slowly because unlike the Electron the Master doesn't have a 16MHz clock signal on the cartridge ports. It uses the same basic driver as the ElkSD-P1 rev 2 but with some improvements, and the prototype currently is managing 27K/sec read and 24K/sec writes. (I posted some pics of this on twitter recently: https://twitter.com/RamtopR/status/1267101598444064768

I'm planning a big brother for the ElkSD64, imaginatively named the ElkSD128, using the same driver and SPI hardware as the previous designs, but because it'll have a beefier CPLD I'm hoping to increase performance a bit. It's only a design so far, no actual hardware yet.

[jpfitzp]

I should have remembered to post something about this, sorry!

The new, faster revision 2 cartridges are finished and presently on sale via Ebay. I haven't made them available at a discount in the For Sale forum yet because sales on Ebay have been far higher than I expected - the rev 2 is proving to be really popular - and it's been a struggle keeping up. Trying to up the number I'm building, but this is a bit hampered because of the present heat wave here in the UK which means my loft workshop, where I do the building, is reaching 34C during the day. Scotsmen aren't made to cope with that

Hopefully I'll have some cartridges available here late next week.

I'm also interested in any comments on something I'm working on now, basically a version of the ElkSD-Plus1 rev2 that works with a Master. The rev 2 PCB was designed to work on both the Plus1 and Master, but it turned out a dual-system card wasn't possible because the CPLD has insufficient capacity for the extra logic required. So there needs to be a separate Master version. This is now working and seems good and stable.

The uncertainty is price; it's going to cost a little over £40, which is a fair bit more than a standard user-port SD interface. The cartridge offers advantages - easier installation and access, faster write speeds (read is about the same), on-board SRAM so MMFS uses none of the Master's memory for slightly better compatibility with anything that needs PAGE at E00 and all 4 SW ram banks, 16K of extra sideways RAM, and MMFS can be updated via software.

But I'm genuinely interested in everyone's view if that's enough to justify the higher price.

Hi there - I have just ordered my ElkSD one for my trust Electron - but I would defo take a Master one once it's developed! Keep being brilliant! John Paul

[Eleccy]

Hi Ramtop,

I recently ordered the ElkSD cartridge for plus 1 from you from Ebay. Works fine, sometimes seems a bit glitchy, need to reseat the cartridge a few times but i think thats down to the decades old computer i dug out my loft. Blown away by how new tech can mesh with old tech like this. Games loading in an instant. Not sure what wizardry enables this.

For a bit of extra info, I was a bit worried it might have some compatibility issues with the slogger master ram board which i fitted to my electron many years ago, but doesn't seem to cause any issue at all. Works well in Turbo mode, with menus loading faster as added bonus. Some games better in turbo mode, some a bit too fast.

Looking forward to taking it further and getting some of my old basic programs put onto MMFS

Anyway, thanks for what you're doing, very appreciative

Cheers

Eleccy

[Ramtop]

Thanks for the kind words!

I did manage to procure an MRB for myself, so all my Electron stuff is tested with it. It's a great product and I'd hate anyone to have to remove it to use an SD interface.

[haerfest]

My apologies as well for resurrecting an old thread

My ElkSD Plus 1 has been glitchy from early on as well, though I can't remember if it was right from the start or started after a few weeks of using it (it's seven months old now). Typically upon a *DCAT it would just hang there, showing nothing but a blinking cursor. No "Card?" or "MMC fault" messages. Applying a mixture of the usual things (reinserting the card, reseating the cartridge, powercycling the Elk) usually got it going after 1-3 attempts. Once going it would be fine until the next power cycle.

(The ATI with a power-drawing Pi Zero I sometimes have attached works fine, as do any ROM cartridges I have. Capacitors in the Plus 1 are all cool, no burn marks or leaks. Happens in both cartridge slots).

Yesterday it misbehaved again, and inquisitive as I am I decided to carefully pry it out of its case. I had to apply a bit of stress to left and right edges of the PCB with a flat screwdriver to free it up, but nothing major. However, it is now glitched permanently...

*DCAT now mostly works, as does *CAT, but *DIN does not (it just prints a few empty lines but does not switch disks). Trying to Shift-boot from disk zero to the typical games menu only restarts the Elk to BASIC with some empty lines being printed.

Then I noticed that the *HELP output was now also corrupted, often times printing parts of what looks to be the BASIC ROM and strangely enough corrupting the letter "E":

At other times it would print a lone "AND", and plot a few random pixels on the screen. Or it would print nothing and just hang. Seems to me like it is executing arbitrary code.

Now I had made a good ROM dump of the ElkSD Plus 1 version of MMFS 1.44 a few weeks ago (to compare it to the original sources to see what was different, did I mention I am curious ), and decided to compare it now to what the Elk was currently trying to execute.

This is what I noticed:

Code: Select all

Address Range  Contents
&8000 - &95FF  As per MMFS 1.44 ROM dump
&9600 - &9FFF  Unknown content
&A000 - &B5FF  As per MMFS 1.44 ROM dump

With the ROM code between &9600 and &9FFF now replaced by unknown data, possibly from the SRAM chip (*), it's no wonder that *HELP, which jumps right in the middle to &98B7 at some point, is glitching out.

(*) I tried writing zeroes first, before reading ROM contents, and managed to get back two to five zeroes in sequence!

In that range at each hard powercycle I get back a slightly different sequence of bytes, but they are clearly variations of the same data. For example, at &9600:

Code: Select all

5E D5 5B 11 99 FE 47 ... Should be 8A A8 20 CA 95 CC C2.
5E D5 20 30 96 AE E5 ... Powercycled.
00 00 20 30 96 AE E5 ... Warm boot, I write zeroes first, got two back.
00 00 00 00 00 AE E5 ... This time got five back.
00 00 20 30 96 AE E5 ... Then two again.

Curiously, the SRAM that is overlaid starts at address &B600, which is just one bit different from &9600... Could that be a hint as to what is going on?

(I followed that bit's address line A13 around and it seems to be properly connected to both the CPLD, the flash chip and the SRAM chip, two connections to each.)

Anyway, my bad for breaking my slightly glitchy but otherwise excellent ElkSD Plus 1. Any pointers as to things to check with a simple multimeter are appreciated, otherwise I think I'll have to place a repeat order soon

[Ramtop]

No need for a repeat order. PM me and I'll arrange to have the ElkSD repaired or replaced, free of charge.

[Square Mezzmer]

Hi Ramtop, sorry for bringing this thread up, I don't know how else to ask

How much is a full service for what should be a fully working ElkSD plus 1 cart? I bought it from an ebay seller and I can't remember it working properly, some slight data corruption on disk writes & reads. Also I cannot find the update tool for 2.x cartridge if this exists yet.

Anyway, I think the cart has a standard error as is mostly working - is there a way to reset the firmware(?) fix it here at home or failing that,

How can I send it to you and how much for payment please?

Cheers

[Ramtop]

If you're in the UK I don't generally charge for repairs to used items, outside of the UK it's just the cost of postage.

I'll PM you the details.