WE EPROM Programmer. ROM images etc

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roganjosh
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WE EPROM Programmer. ROM images etc

Post by roganjosh » Mon Nov 25, 2019 9:57 am

I recently acquired a Watford Electronics Eprom programmer from eBay. It's not an Adder and doesn't say 'Mk II' on the case (though it does look like one). I assume it may be a 'Mk I'. It was in a bit of a state. Ultra-thin mains cable, blown chassis fuse, shorted bridge rectifier, the leads of some components snipped and re-soldered and three lifted tracks on the PCB. Having sorted that out I've tried it with V4 and V8 ROM images found on this site. The version 8 ROM image looks as though it has been hacked. It has two main menu entries for 2764s, one of which, when selected, seems to be for a 2564. The programming option for all devices just brings up the hex editor screen. The V4 image is more promising. With that the programmer can read/program/verify 27128s however it fails blank checks/reads on 2564s - the checksum is never the same and there is the occasional block of 0xFCs rather than 0xFFs.

Before blaming the hardware I spotted in a previous thread that hoglet has several ROM images which have not yet been uploaded.

EPROM V3.Mark David 01 (C)MDM Software 1983 82 2000 afd9280b4c94180dd7185ef1fc9768ae
EPROM V4.Mark David 01 (C)MDM Software 1984 82 2000 1aa1b141b41c860b8d77efd77d38925f
EPROM V4.Mark David 01 (C)MDM Software 1984 82 2000 89c4ba6124b87d0451894692f4b129a2
EPROM V4.Mark David 01 (C)MDM Software 1984 82 4000 1c1f291129bd2e8cd2b01fafa07e1dfe
EPROM V8 08 (C)Mark David c2 4000 c7af6b60a8b19e14de16b030d5ee426f

Given that it's certainly worthwhile for me to see if any of those solve the problem, and that it's potentially useful data for others, he's kindly suggested (via PM) starting this thread and that he'll upload them here. Btw Dave, are those MD5SUMs? It'd be interesting to match them against other images on this list and the two on archive.retro-kit.

Having examined the PCB (anyone have a schematic?) it looks as though 2564s might not be handled properly in that all devices are given a Vpp of 21V whereas the 2564 requires 25V. That shouldn't affect the reads though (and I can always make a small adapter, if necessary, and feed Vpp from my bench power supply). The 2532 entry is probably there for TMS2532A 21V jobbers. Of course it's 2564s I'm particularly interested in as, setting aside the top 4 pins, they're a potential replacement for the ROM in a ZX Interface 1. Another route I could take would be to do an adapter on the 2764 (untested, some test EPROMs in the post) side.

Anyway, I've got spares of all the ICs in my collection so they can be tried, if necessary, after testing the ROMs and further PCB inspection.

Alan

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hoglet
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Re: WE EPROM Programmer. ROM images etc

Post by hoglet » Mon Nov 25, 2019 11:19 am

Hi Alan,

Attached are four of the ROMs:
eprom.zip
(25.08 KiB) Downloaded 36 times
I can't locate the fifth one at the moment:
- EPROM V4.Mark David 01 (C)MDM Software 1984 82 2000 1aa1b141b41c860b8d77efd77d38925f

And yes, the signatures are md5sums.

Dave

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Re: WE EPROM Programmer. ROM images etc

Post by roganjosh » Mon Nov 25, 2019 7:50 pm

Thanks Dave. For completeness there is this v4 posted elsewhere in this forum:

8ccf49a17e39f2d9ce22c03afbf99147 "EPROM V4 Mark David (C) MDM Software 1984"
WTFEPRM.ROM
(16 KiB) Downloaded 18 times
The ROMS on http://archive.retro-kit.co.uk/bbc.nvg. ... index.html are covered in your zip (as v4 and v8).
The ROM in another thread, given in EPROM__1.zip, is the same v8 file.

That seems to cover it with the possible exception of the v4 file you can't find.

Sadly none of the images fix my current problem with 2564s, however it's been a useful exercise gathering the MK I/II images together.

Alan

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hoglet
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Re: WE EPROM Programmer. ROM images etc

Post by hoglet » Mon Nov 25, 2019 8:11 pm

roganjosh wrote:
Mon Nov 25, 2019 7:50 pm
That seems to cover it with the possible exception of the v4 file you can't find.
Here's that final ROM:
WEPROM.zip
(5.65 KiB) Downloaded 20 times

Code: Select all

1aa1b141b41c860b8d77efd77d38925f  R.WEPROM
Dave

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Re: WE EPROM Programmer. ROM images etc

Post by Elk Towers » Mon Nov 25, 2019 8:47 pm

I am almost certain that there are pin designation differences between 2764 and 2564 chips, so unless there are some jumpers to change these you may need to make an adaptor
Nick

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Re: WE EPROM Programmer. ROM images etc

Post by roganjosh » Mon Nov 25, 2019 8:57 pm

Thanks, but the design of the WE programmer is such that an internal 8255 is programmed by the ROM software to route the pins properly.

Alan

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Re: WE EPROM Programmer. ROM images etc

Post by roganjosh » Wed Nov 27, 2019 9:24 pm

Here's a just-completed schematic for the programmer. Please let me know if something looks wrong.
WE-Eprom-Programmer.pdf
(103.59 KiB) Downloaded 30 times
It should be a help in sorting it out and vital for working out the correct FCxx addresses to use. It was not possible to extract the 8255 without damage to the socket. Having replaced the socket the programmer is stubbornly refusing to work at all. Oddly pin 6 ('E') on IC1 isn't tied to Vcc and I can't see how it can work without that. Measurement shows there is no internal pull-up. Anyway, I've added that connection to the schematic and will do the same on the PCB itself in the next few days. The other difference from the original is to sort out an unused gate on the 74LS00 which had floating inputs. The schematic fixes are there as I may well do a new PCB design for it once it's all singing and dancing (with possible addition of selectable 21/25V Vpp), given that the PCB has been mistreated by a previous owner.

Alan

Edit: Correct C10 in schematic.
Last edited by roganjosh on Sat Nov 30, 2019 2:14 pm, edited 1 time in total.

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Re: WE EPROM Programmer. ROM images etc

Post by 1024MAK » Wed Nov 27, 2019 11:28 pm

Were the chips 74xx or 74LSxxx types? Only the inputs on these float to a logic high if left unconnected.

I’ve seen a number of designs of expansions / interfaces for various computers where the designer did not bother to connect unused inputs of 74xx or 74LSxxx gates/logic.

Mark

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Re: WE EPROM Programmer. ROM images etc

Post by roganjosh » Thu Nov 28, 2019 6:16 am

They were all LS types. The 7400 still is, the 74138s are currently HCT types. Thanks for the floating info; I did refer back to 74 series data sheets yesterday and didn't chance upon any that said what happened to voltage levels of unused gates. From what you say, following best practice may definitely be essential for the CMOS devices and is something I've always been happier doing.

Alan

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Re: WE EPROM Programmer. ROM images etc

Post by 1024MAK » Thu Nov 28, 2019 8:31 am

It is best practice to tie unused inputs on 74xx and 74LSxx to either 0V or to Vcc via a 1kΩ resistor (which can feed multiple inputs).

It is essential to tie unused inputs on CMOS inputs including 74HCxx, 74HCTxx, 74ACxx etc. to either Vcc or 0V. No resistor needed for these.

Alternatively, unused inputs can be connected to another existing logic signal.

Mark

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Re: WE EPROM Programmer. ROM images etc

Post by roganjosh » Sun Dec 15, 2019 10:15 am

The EPROM programmer is now working. It took longer than expected to fix as a UK supplier sent me some bad 8255 ICs. You also have to be very careful with suppliers of 2564 EPROMS. A heuristic seems to be that if the ICs don't have a raised platform around the window then they're probably not 2564s.

The schematic I provided above (recently changed to correct a capacitor location) clearly shows that there is no automatic 21/25V voltage selection nor a switch for the purpose. The programmer appears to rely on 2564s being able to be programmed at 21V. That does indeed work, though the longevity of the programmed data will presumably suffer. Given that there's rarely a need to do a 2564 these days it's no great hassle to open the programmer case and adjust the preset to provide 25V Vpp when needed, changing it back to 21V when done. That problem will go away when I get round to doing a new PCB.

Anyway, it's good to have a programmer that will do the old high Vpp chips and has also been a nostalgia trip as I had a Mk II in ages past. It now opens up the possibility of trying a 2564 in a ZX IF1.

Alan

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Re: WE EPROM Programmer. ROM images etc

Post by 1024MAK » Sun Dec 15, 2019 1:20 pm

Well done 👍 :D

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Re: WE EPROM Programmer. ROM images etc

Post by roganjosh » Fri Jan 17, 2020 10:06 am

I noticed that none of the version 4 images work with the Master 128. This is due to the ROM header specification combined with a subsequent osbyte 8E call. I've modified the version 4 image to correct the problem. This image should now work on both M128s and Bs:
EP104M.ROM
(8 KiB) Downloaded 13 times
This is based on the file "v4" which is provided above in the zip file "eprom.zip" . Only 3 bytes have been changed, all related to the header. I've looked at the other version 4 images in this thread and most, unlike "v4" which is 8K, have been manually increased in size to 16K. That's been done by a variety of means e.g. one file looks like it's been loaded into a programmer as 8K and then saved back out as 16K whereas another appears to be the 8K file catenated with itself. There appears to be no difference in functionality between the padded images and the "v4" image. The only other 8K image is "R.WEPROM". That image looks to be a corrupted version 4 - one change being to redirect an interrupt routine to an undocumented opcode (the other changes make no sense either). The "v4" file is probably the original of the set - that ties in well with it being the one on the archive site.

Alan
Last edited by roganjosh on Wed Feb 19, 2020 7:00 am, edited 1 time in total.

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Re: WE EPROM Programmer. ROM images etc

Post by DaveLecky » Tue Feb 18, 2020 2:30 pm

Hi Folks,

Are these rom images suitable for all WE programmers, or are they for individual models....

I have the Adder, supplied with v.1.03 rom and would like to try a higher version if compatible.

Thanks

Dave
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Re: WE EPROM Programmer. ROM images etc

Post by Pernod » Tue Feb 18, 2020 3:39 pm

DaveLecky wrote:
Tue Feb 18, 2020 2:30 pm
Are these rom images suitable for all WE programmers, or are they for individual models....

I have the Adder, supplied with v.1.03 rom and would like to try a higher version if compatible.
No, each programmer requires specific software.

The only known dumped version of Adder is v1.01 so your 1.03 is probably the latest for that programmer. A dump of your ROM would be appreciated too.
- Nigel

BBC Model B: ATPL Sidewise, Acorn Speech, 2xWatford Floppy Drives, AMX Mouse, Viglen case, BeebZIF, etc.

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Re: WE EPROM Programmer. ROM images etc

Post by DaveLecky » Tue Feb 18, 2020 7:37 pm

Hi Folks,

Here is the ROM image supplied with my WE ADDER Eprom Programmer.
Attachments
ADD103.zip
(7.9 KiB) Downloaded 14 times
Electron Plus 3 and plus 1, AP6 and Home made MMFS PP SD interface
Electron Plus 1 Pres AP3/4 with drive
Beeb issue 7 with IFEL 16 socket Rom/Ram board, IFEL SD card, Floppy interface
Master 128, BooBip multi OS,IFEL SD card
StrongA RPC, A3020

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Re: WE EPROM Programmer. ROM images etc

Post by Pernod » Tue Feb 18, 2020 9:56 pm

DaveLecky wrote:
Tue Feb 18, 2020 7:37 pm
Here is the ROM image supplied with my WE ADDER Eprom Programmer.
Thanks, much appreciated.
- Nigel

BBC Model B: ATPL Sidewise, Acorn Speech, 2xWatford Floppy Drives, AMX Mouse, Viglen case, BeebZIF, etc.

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