ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby sixxdog_uk » Sat Apr 01, 2017 5:06 pm

hoglet wrote:Does it work then?




Has your board arrived Dave?

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby hoglet » Sat Apr 01, 2017 5:11 pm

Hi Alex,
sixxdog_uk wrote:Has your board arrived Dave?

Yes indeed, it arrived this morning. They look really nice boards. Thanks for taking all this on!

I thought I already had all the components, but turns out I'm missing the IDC sockets, so there will be a brief delay in construction.

Dave

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby CMcDougall » Sat Apr 01, 2017 5:16 pm

MartinB wrote:Colin - you haven't soldered either of those 20-ways User Port connectors have you? .

Yes #-o after finding the male connector not female, I lost thought for a micro second , so thats another 1:30 hrs to unsolder those :lol:

it does work, snapper & hopper, loaded in other roms, then noticed EMMFS not working... due to above :D
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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby 1024MAK » Sat Apr 01, 2017 5:26 pm

MartinB wrote:*** Alert! ***

Colin - you haven't soldered either of those 20-ways User Port connectors have you? They go on the opposite side to the components - unusual I know but it was all about the tracking conundrums...

Should have looked at the picture here :lol:

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby 1024MAK » Sat Apr 01, 2017 5:28 pm

sixxdog_uk wrote:
MartinB wrote:I of course have never made that schoolboy error... [-( :---)

You were also going to tell folk to replace D3 with a link and lose D4 & R4...? :wink:



I did mention it in the parts list sheet that I've sent out with them.

I included them in the parts in case people wanted to play about with the battery feature but i did say its now been superseded by EEPROM :)

I'm assuming the boards will still work with d3 in place a not a link? , also with d4 and r4 in place? Just a few extra pence on parts.

Doh!

Yes, of course the RAM or ROM or EPROM or EEPROM will still work - as long as you pray to the Flux Capacitor Mecca first before powering it up :D

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby sixxdog_uk » Sat Apr 01, 2017 5:34 pm

MartinB wrote:But, just to be clear for everyone on the other issue, the connectors must go on the non-component side, they are electrically reversed if not. Colin will have to move his.... :(



Im going to edit the sheet that i send out and put in bold that the connectors go on the flip side of the board. :!:

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby sixxdog_uk » Sat Apr 01, 2017 5:39 pm

JUST TO BE SURE THIS TIME :lol:

This one ?? #-o
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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby MartinB » Sat Apr 01, 2017 5:49 pm

Looks ok to me... :lol:

( Other connector types are available. )

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby sixxdog_uk » Sat Apr 01, 2017 5:52 pm

MartinB wrote:Looks ok to me... :lol:

( Other connector types are available. )



Oh the shame of it #-o #-o #-o #-o

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby roland » Sat Apr 01, 2017 7:09 pm

Just a question .... what is IC 8 (not mounted in the pictures) intended for?
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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby sixxdog_uk » Sat Apr 01, 2017 7:31 pm

roland wrote:Just a question .... what is IC 8 (not mounted in the pictures) intended for?



I think it was future expansion , I send out a DIL in my kits as i hate unpopulated parts of boards :P

Martin B will no doubt be able to tell you more. :)

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby 1024MAK » Sat Apr 01, 2017 7:35 pm

roland wrote:Just a question .... what is IC 8 (not mounted in the pictures) intended for?

It's a "spare" position included in case any extra logic gates are needed. So far, it has only been needed for some boards fitted with SRAM when used with a Plus 1 that does not co-operate...

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby sixxdog_uk » Sat Apr 01, 2017 7:40 pm

DELAY DELAY DELAY

Sorry guys , but due to my utter incompetence I have had to order new 9 Way Sockets for PL3 - FEMALE (NOT MALE AS I ORDERED)

As a result , any kits or pre-built will be delayed by 2 days while I wait for RS to deliver the replacements.

Luckily only 3 StarDotters were affected and I've sent out PM's , I'll of course send out new parts as soon as RS Deliver.

ON ANOTHER NOTE , PLEASE NOTE : The 20 Ways and the 9 Way connectors go on the reverse side of the board , not the same side as all the other components. PLEASE SEE PHOTO ON. http://www.retro-kit.co.uk/page.cfm/con ... RAM-board/

Other than that , all is on course.

Sorry for the delay.

Alex :)
Last edited by sixxdog_uk on Sat Apr 01, 2017 10:32 pm, edited 1 time in total.

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby MartinB » Sat Apr 01, 2017 7:56 pm

Yeah, as Mark says, I designed-in a spare IC slot from the outset principally in case any new memory chips came along in the future that might require additional decoding or gating logic. It was also of course a nice insurance policy against my having made any goofs in the design which (thus far) hasn't transpired. However, there was though, as Mark alluded to, the curious case of the corrupting sram where I was able to use IC8 to provide a fix for (most) affected users.

So, in summary answer to the question, IC8 is probably not needed and is just a spare - feel free anyone to use for it adding your own improvements or bespoke functionality.... 8)

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby sixxdog_uk » Tue Apr 04, 2017 1:47 pm

UPDATE


All remaining kits and parts have been sent out today.

Fully built boards to follow shortly.

Still have some of the boards available for both kits / boards and pre-builds , but hurry they'll be gone soon ;) :^o

Thanks for all the support and orders everyone =D>

Alex

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby sixxdog_uk » Wed Apr 05, 2017 9:25 pm

Built and ready to go.

Hats off to the original EUP / UPURS DEV Team , this rocks!!
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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby roland » Sat Apr 08, 2017 7:32 pm

I have received my boards too. Thanks Alex.

Question: I didn't buy this board only for UPURS, but also for connecting a MMC interface to it. After all, it has also a user port on it. I want to program both the UPURS and a DFS in a 32k EEPROM. Will that work or can I expect some issues with that setup?
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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby MartinB » Sat Apr 08, 2017 8:42 pm

roland wrote:I didn't buy this board only for UPURS, but also for connecting a MMC interface to it. After all, it has also a user port on it.

Heh heh, that almost sounded like an apology... :lol:

Of course there is no obligation or expectation whatsoever that anyone will use the UPURS feature, it's just there if you need it! It wasn't me who spun the name UPURS in the title, that was Alex :wink:. I named the original project simply EUP (Electron User Port), because, as you so rightly point out, that's exactly what it is and I only bunged the UPURS components on there coz I could!

Anyway, the UPURS rom is very much a sleeper and doesn't do any persistent background VIA configuration, it only initialises the hardware and any memory it uses if any of the *UPxxxx commands is called so as far as I'm concerned, the UPURS rom software will happily co-reside with anything else that uses the EUP 6522 User Ports. I can't conversely speak for any of the MMC stuff because I don't use it but I expect the same is true. So, I see no reason at all why you shouldn't have UPURS and a DFS (of any kind) in a 32k rom, whether that's the one on EUP or one on another cartridge.

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby hoglet » Sat Apr 08, 2017 9:28 pm

Roland,

I also would expect it to work.

The 9-pin UPURS socket is connected to Port A and MMFS uses Port B (as do all MMC file systems due to the shift register being connected to CB1/CB2).

If you have any problems just shout.

My only concern regarding MMC file systems is the regenerated 1MHz clock into the 6522 is indeed a bit glitchy. According to Martin this a known issue (mentioned here with pictures).

This is what I'm seeing on pin 25 of the 6522 when I do a *CAT:
IMG_0873.JPG

IMG_0874.JPG

The width of this glitch varies between 30ns and 60ns.

That said, so far MMFS has been working flawlessly, and others report the same. i.e. there doesn't seem to be any effect on the signals to the SD card. So at the moment this is of academic interest only.

Dave

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby MartinB » Sat Apr 08, 2017 9:47 pm

Dave wrote:According to Martin this a known issue

Yes, it's a known 'issue' (I think I prefer design quirk :wink:) in the sense that the logic I've used for maintaining a constant 1MHz clock does knowingly allow glitches through to the 6522 but in extensive testing, none of the numerous VIA chips I tried ever acted on one of these glitches. Although I don't use MMC, I did test a basic unit, I think possibly one of Martin Mather's original designs (?) together with a range of other User Port-based peripherals and all worked absolutely fine. The additional focus for me from a personal perspective was UPURS and later I2C and again, these both work perfectly with EUP.
So, perhaps a better design could be implemented (I was restricting my chip count) but I don't think it's in any way necessary and as I said in the original thread, my VIA timer-based tests of EUP proved to be extremely accurate and commensurate with the same tests on a Beeb.

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby CMcDougall » Sun Apr 09, 2017 10:03 am

yes Roland, that will be perfectly fine, my one been doing it for years, & so does this new blue one.

only problem is with a MMC rom & a DFS, so I change in MMC disc/disk to card/dmmc, sorted!
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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby hoglet » Sun Apr 09, 2017 2:33 pm

hoglet wrote:That said, so far MMFS has been working flawlessly, and others report the same. i.e. there doesn't seem to be any effect on the signals to the SD card. So at the moment this is of academic interest only.

Hmm, I might have spoken too soon.

I've done some more testing and I'm seeing MMC Write Errors when trying to *SAVE anything, or when trying to *FORMAT a disk.

The specific configuration that is failing for me is:
- MMFS 1.33 (EMMFS)
- EUP (latest batch from Alex))
- R6522-31 (date code 8242)
- Sandisk Ultra 16GB SDHC card

This particular 6522 works fine in my Beeb.

I've tried a couple more things:
- swapping to a SY6522 (8352)
- bypassing the 1MHz clock regeneration circuitry on the EUP by connecting Phi0 from IC5B pin 6 to 6522 pin 25, and connecting 6522 pin 24 (CS2) to +5V

With either of these changes the write errors immediately go away.

This does seem to indicate that the clock glitches do have an effect on some 6522s. :(

Martin, is UPURS operation dependent on the 6522 being clocked at 1MHz all the time? It seems to work find with the above mod in place.

Dave

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby MartinB » Sun Apr 09, 2017 4:06 pm

Hi Dave

Martin, is UPURS operation dependent on the 6522 being clocked at 1MHz all the time? It seems to work find with the above mod in place.

UPURS is obviously just my name for the transfer system as a whole as isn't a protocol in itself, the actual technical detail going on behind the scenes (as I'm sure you know) is bit-banging 115k RS232 through a 6522 data line with another data line for handshaking and then all doubled-up to give the half-duplex link. So, because RS232 is asynchronous, the criticality comes with the RS232 bit periods for each 10 bits of data (one start, one stop, no parity) and these need to be kept close to 8.7us (which is why I have to use some cycle jittering) with any errors soon accumulating across the bits causing things to quickly fall over. So, the timing begins with the expending of instruction cycles in the UPURS code but the 6522 must then promptly 'clock' when the next bit is written and the whole process is predicated on either 1 or 2 MHz operation with the code being written accordingly. I don't use the CBn (or CAn) lines, just the PBn (or PAn) data lines.

I cant't quite visualise what the mod is doing off the top of my head (being slow, busy day) but whatever effect it has, I assume that the UPURS software can still toggle the 6522 data lines at 1MHz so as not to impact the RS232 bit timing? I'm not sure if that that has fully answered your question....?

Incidentally, to check the operation of UPURS properly, you really need to transfer a full SSD from the PC to a target machine DFS floppy using UPSSD, transfer it back to the PC with UPXSSD and then carry out a binary compare of the source and transferred images. Repeat several times! This is the only way to be 100% confident that no single-bit errors are occurring.

Edit thought : I had to stipulate that UPURS must run in rom on an Elk to insulate the bit-bang engine from the Elk's variable clock throttling but in doing so, had I actually unwittingly made the code inherently immune to the 6522 clocking? If so, that would explain why your 'clocking' the VIA with phi might work and would imply that the 1MHz maintenance logic isn't needed for any rom-based 6522 access, only for code running from ram that assumes a 1MHz 6522 clock?
Last edited by MartinB on Sun Apr 09, 2017 5:02 pm, edited 1 time in total.

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby hoglet » Sun Apr 09, 2017 4:53 pm

MartinB wrote:I cant't quite visualise what the mod is doing off the top of my head (being slow, busy day) but whatever effect it has, I assume that the UPURS software can still toggle the 6522 data lines at 1MHz so as not to impact the RS232 bit timing? I'm not sure if that that has fully answered your question....?

Yes, it should not affect the rate that the 6522 data lines can be toggled.

I was really just checking if any part of UPURS depended on the the 6522 timers running at 1MHz. Sounds like the answer is no.

The mod is simply clocking the 6522 directly off the delayed Phi0. The advantage being that the clock doesn't contain any glitches. The disadvantage being that it's speed varies, sometimes 1MHz, sometimes 2MHz.

I don't yet have a good understanding of exactly what is going wrong with SD Card writes, but the effect is pretty drastic, as the disk catalogue ends up getting corrupted very quickly. I'll do some more testing next week, so that if anyone else hits this we know which way to steer them.
MartinB wrote:Incidentally, to check the operation of UPURS properly, you really need to transfer a full SSD from the PC to a target machine DFS floppy using UPSSD, transfer it back to the PC with UPXSSD and then carry out a binary compare of the source and transferred images. Repeat several times! This is the only way to be 100% confident that no single-bit errors are occurring.

I created a disk containing 12 copies of BBC Basic, and have successfully transferred it back and to a couple of times, MD5umming the result each time. It's definitely working without errors.

Dave

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby hoglet » Sun Apr 09, 2017 4:56 pm

roland wrote:Question: I didn't buy this board only for UPURS, but also for connecting a MMC interface to it. After all, it has also a user port on it. I want to program both the UPURS and a DFS in a 32k EEPROM. Will that work or can I expect some issues with that setup?

Roland, I'll be very interested to see whether you have any issues with the SD Card interface.

Are you planning to use MMFS?

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby MartinB » Sun Apr 09, 2017 5:04 pm

Dave - just added an edit to my previous post as you were posting....

I wrote:Edit thought : I had to stipulate that UPURS must run in rom on an Elk to insulate the bit-bang engine from the Elk's variable clock throttling but in doing so, had I actually unwittingly made the code inherently immune to the 6522 clocking? If so, that would explain why your 'clocking' the VIA with phi might work and would imply that the 1MHz maintenance logic isn't needed for any rom-based 6522 access, only for code running from ram that assumes a 1MHz 6522 clock?


Yes, I think this is possibly why - UPURS as a package is definitely not tolerant of clock variation because the RS232 bit timing tolerance at 115k baud is tiny, but I think that what I hadn't twigged to was that by necessarily restricting Elk UPURS to rom, both the code and the 6502 are being driven by a stable clock during a data burst so actually, the clock adjuster isn't needed. It is only of value where the 6522 timers are being used, for example as per the tests I wrote about on the original thread.

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby roland » Tue Apr 11, 2017 7:41 pm

hoglet wrote:Roland, I'll be very interested to see whether you have any issues with the SD Card interface.
Are you planning to use MMFS?


At the moment I'm very busy with lots of things, so it will take a while before I build this interface. I'm not sure which FS I'm going to use. MMC on the Elk is completely new for me. Of course, I'll keep you informed when I have made some progress.
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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby MartinB » Thu Apr 13, 2017 6:37 am

I've had another look at 'the glitch' since MMFS seems to have exposed a potential detrimental consequence with certain 6522 types. Essentially, it's occurring because in my regenerated 1MHz clock sync circuit, TTL propagation delays in the main IC2 nCS2 circuit and the preceding gates means that nCS2, and hence significantly the LS393 reset, is arriving a few tens of nano-seconds late, occasionally allowing a narrow glitch through to the 6522 Phi2 input. Following some investigations last night, I've found that if I fractionally slug the 1MHz clock rising edge at the input to the Phi/1MHz switch gate at IC4d by simply using a 220pf capacitor to ground, the glitch is completely eradicated. Some pics....

This is the typical glitch that occurs when the 6522 is accessed and EUP switches the clock source....

Image


This is where the 220pf disc ceramic is added....

glitch mod.jpg



And this is the EUP 6522 clock output with the cap in place....

Image


@Dave (hoglet) - would you be able to try this please? I could do with a fully independent check with different hardware and also, I don't have any MMFS kit to be sure that it cures the SD card hiccup. I guess that as long as the glitch is fixed, the MMFS issue should also be sorted but since we don't fully understand why only some 6522's are affected, it would be good to try the one that you know was failing. I simply connected the 220pf ceramic at the back of IC4 from pin 11 to ground. Thanks.
.
.
.
.
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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby hoglet » Thu Apr 13, 2017 7:28 am

Sure, I can give this a try today.

The glitch I was seeing was between 20ns and 60ns wide, which seems so much more significant than the one you have captured that I wonder if the mechanism is different. The 60ns bound I suspect comes from the 16MHz clock cycle time.

I've done a bit more testing with the different 6522s, and it does seems that all are susceptible to a greater or lesser extent. They also seem much more susceptible when cold than when hot. With one of them (the SY6522), once the system has been running for a couple of minutes, it seems reliable. Because of this temperature induced variation, it's actually quite hard to be definitive about whether a given change had made a positive difference or not.

One thing I need to do is to re-install the mod that bypasses the 1MHz clock regeneration, and re-confirm that there is no problem with any of the 6522s, especially when running from cold.

Dave

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Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

Postby MartinB » Thu Apr 13, 2017 8:31 am

Thanks Dave. I think I was actually capturing glitches of that order too (the pics were just random examples) although there is of a course a variance between none and the largest glitches of 50ns+. I know the 'fix' is a little dumb but I was looking for something that might sort the issue without recourse to an active mod. At the end of the day, there is the spare IC slot so I've no doubt we can sort it one way or another but it would obviously be much better if the fix can come from something simple and I'd prefer it if we can maintain the original aspiration of a fixed frequency clock regardless of Elk mode or function.

(The moral is, never work with children, animals or Acorn Electrons......)


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