MFX - Installation, Usage, Issues, Questions, Problems

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Dave
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MFX - Installation, Usage, Issues, Questions, Problems

Post by Dave »

Hi,

now that MFX has stated to ship, albeit in very small numbers, a few pointers on what to do if you have any issues with installation and/or usage of MFX. I spent a considerable amount of time preparing the Operator's Guide, the latest version of which will always be available on this page

http://primrosebank.net/computers/mtx/p ... _usage.htm

Please ensure that you download and READ this Guide prior to installing and using MFX. I appreciate that the document is long and, in places, somewhat wordy, but there is a Table of Contents and a tiny index which I will expand as time allows. I am pretty sure that this document will answer most, if not all, of the questions that you might have.

Whilst I am always happy to help with any problems or answer any questions, I have spent considerable time on the Operator's Guide, so please refer to it first. I may be (OK, I AM!) getting less patient in my old age, and I don't have the time to personally answer every question whose answer is covered in a manual that took me many hours to complete.

However, if having at least looked at the manual, you find that your issue is not covered, or the Operator's Guide is unclear, then by all means ask. If the Guide is deficient, I will edit it as required.

For general usage questions and observations, you might also like to consider starting a new thread in this forum - that way, the information can be more easily shared with other current and prospective MFX users.

regards
Dave
acsi
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Re: MFX - Installation, Usage, Issues, Questions, Problems

Post by acsi »

So my MFX machine started misbehaving. At first it would occasionally display an incorrect serial number, this moved on to memory size being incorrect and the frequency increased. Now it will not find a drive and will reset with full screen colours displayed.
So I thought (as I normally incorrectly do) that maybe now is a good time to upgrade the firmware whilst testing the eprom and GAL.
The Eprom erased and programmed fine. Unfortunately the GAL was not so nice.
I am using a G540 programmer on an old Toshiba XP laptop. The software says it will do a Lattice GAL 22V10D but this is the first time I've programmed a GAL so am a little unsure.
The GAL erases ok but doing a read afterwards shows all 1's apart from the last line where it has 4 zeros.
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After programming it fails the verification and reading what's there is never the same.

So do I possibly have a faulty GAL? or is my programmer not actually doing what it should? Or am I not doing it correctly (this is possibly the most obvious answer BTW :lol: )?
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Dave
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Re: MFX - Installation, Usage, Issues, Questions, Problems

Post by Dave »

I don’t know anything about the G540 programmer, but I do know that my TL866a, although when I bought it, listed the GAL22V10 as a supported device, would not correctly program the GAL. The symptoms were similar to those you describe, it would appear to program the device, then fail the verify.

Although the firmware has been updated, the release notes for the upgrade include mention of a fix for GALs, I use a legacy EMP20 programmer (also with Windows XP) to program the GALs.

That being said, the fact that some (repeatable?) bits are not being cleared on an erase do suggest that either there is a device compatibility issue with your programmer or software or there is indeed a fault with the GAL.

Whether the GAL could have caused your previous issues, I’m not sure.

I can supply a replacement GAL for the cost of the part and postage, but, given your location, it would probably be quicker to try and source one locally?

p.s., I just noticed that you have what appears to be the encryption flag set to on. If that was the case when you reprogrammed the GAL, that probably prevents the read back from working. Can you try it with no encryption set. (It is possible that encryption is a one time deal, once it’s set, there’s no going back!)

p.p.s. I just looked at the data sheet for the GAL, you should be able to reprogram it and clear the encryption bit.

Regards
Dave
acsi
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Re: MFX - Installation, Usage, Issues, Questions, Problems

Post by acsi »

Thanks Dave,

So some user error. Unfortunately even with the encryption turned off it still fails on verify.

I've got some more chips coming so it'll need to wait now until they arrive. I'll let you know how I get on.

Edit: Although Encrypt (which was after verify in the programming sequence) has been removed it still says encrypt in the "Encrypt Config" box which I cannot seem to find a place to turn it off? hmm it'll have to wait as I need another chip to prove where the problem lies.
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Dave
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Re: MFX - Installation, Usage, Issues, Questions, Problems

Post by Dave »

Doing a quick search on the web about the G540 and GAL22V10 throws up a couple of posts about some users not being able to program the GAL, possibly down to the USB programmer not being able to generate enough voltage to reprogram the GAL properly.

That may or may not be the issue here, but as you say, let us know how you get on with the GALs that you have on order

regards
Dave
Martin A
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Re: MFX - Installation, Usage, Issues, Questions, Problems

Post by Martin A »

I found a copy of the data sheet, bit positions 5828 to 5891 are the "signature bytes". So are not part of the fuses that set up the AND/OR logic.
An electronic signature (ES) is provided in every GAL22V10 device. It contains 64 bits of reprogrammable memory that can contain user-defined data. Some uses include user ID codes, revision numbers, or inventory control. The signature data is always available to the user independent of the state of the security cell.

The electronic signature is an additional feature not present in other manufacturers' 22V10 devices. To use the extra feature of the user-programmable electronic signature it is necessary to choose a Lattice Semiconductor 22V10 device type when compiling a set of logic equations. In addition, many device programmers have two separate selections for the device, typically a GAL22V10 and a GAL22V10-UES (UES = User Electronic Signature) or GAL22V10-ES. This allows users to maintain compatibility with existing 22V10 designs, while still having the option to use the GAL device's extra feature.

The JEDEC map for the GAL22V10 contains the 64 extra fuses for the electronic signature, for a total of 5892 fuses. However, the GAL22V10 device can still be programmed with a standard 22V10 JEDEC map (5828 fuses) with any qualified device programmer
Which probably explains why you can see some zeroes.
acsi
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Re: MFX - Installation, Usage, Issues, Questions, Problems

Post by acsi »

OK so whilst waiting for the new GAL to arrive I may have purchased a T48 programmer (Supposed to be a TL866 successor or something like that). The advantage being that I now don't need to get out my old XP laptop and the software seems easier to understand.
So before the new programmer arrived I had read an old GAL20V8 I have here then erase and reprogram it ad it all worked fine using the G540.
Today the new programmer arrived and I tried it out with the GAL from the MFX. Actually I managed to get it programmed correctly...
So now to try it out in the MFX.
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Dave
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Re: MFX - Installation, Usage, Issues, Questions, Problems

Post by Dave »

That sounds like progress.

Going back to the original problems . . . . .

As I mentioned earlier, a GAL fault is unlikely to have been the root cause of your problems. The GAL is only doing the memory decoding, it has no impact on the serial number displayed, that is done in the FPGA.

The most likely issue is probably the connection between the MTX and MFX. The MTX edge connector is a regular source of problems with add on boards. It wasn’t a great design and even back in the day, caused problems, to such an extent the Memotech resorted to soldering the connections between the computer board and add on boards.

Unless you have had the MFX board removed while you were working on it (?), you should try removing and replacing the MFX board to try and get it to make a better connection. You could give the MTX edge connector a clean too,

Regards
Dave
acsi
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Re: MFX - Installation, Usage, Issues, Questions, Problems

Post by acsi »

As I mentioned earlier, a GAL fault is unlikely to have been the root cause of your problems. The GAL is only doing the memory decoding, it has no impact on the serial number displayed, that is done in the FPGA.
Yep that's what hit me about 3 minutes after successfully writing to the GAL.
The most likely issue is probably the connection between the MTX and MFX. The MTX edge connector is a regular source of problems with add on boards. It wasn’t a great design and even back in the day, caused problems, to such an extent the Memotech resorted to soldering the connections between the computer board and add on boards.
I did consider this to start with and gave the connector a good clean. No change in behaviour at the time.
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Now that's a nice sign. New firmware works and the machine is stable for now although it's only had around 30mins use it's been perfectly stable with no issue's.

Fingers crossed :D
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