Hi From London England

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Ruptor
ROM Dongle
Posts: 46
Joined: Fri Dec 20, 2019 2:23 pm

Re: Hi From London England

Postby Ruptor » Mon Jan 06, 2020 1:12 am

From the above ROM swapping tests above I had the impression the lower ROM was faulty so today I installed a Universal programmer I bought a few months ago to test the chips. After jumping through hoops on Windows 10 I managed to get it working but I searched the data base for the ROM type and couldn't find the 23256 or 23128 numbers. I assumed they are OTP types so I used the 27256 type that is not an OTP but should be pin compatible. The lower ROM shows gives pin faults on the five pins 15 to 19 and the upper ROM passes the pin test but I can't read either of the ROMs. The pin fault stops the 23256 from being read and the read chip ID prevents the 23128. I might be doing something stupid with the type selection but I think the chips have the same pins and the five that give a pin error are the lower five of the data bus that is the same on both chips so it does look like the 23256 is faulty. It is annoying that I can't read the 23128 chip either for a different reason that I can't fathom. Of course it might that I just don't know how to work the programmer yet and I am doing something stupid. :roll:


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tofro
QL Wafer Drive
Posts: 1715
Joined: Sun Feb 13, 2011 10:53 pm
Location: SW Germany

Re: Hi From London England

Postby tofro » Mon Jan 06, 2020 9:00 am

If you know a chip is pin and programming voltage compatible with another one, my MiniPro programmer allows to skip the "read chip ID" step (There's an unremarkable check box somewhere). I typically need to uncheck that one to make it work with Flash EPROMs that I can't get programmed otherwise.
Maybe your software has something similar.

Tobias


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Ruptor
ROM Dongle
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Joined: Fri Dec 20, 2019 2:23 pm

Re: Hi From London England

Postby Ruptor » Mon Jan 06, 2020 11:02 am

The flash tick box is on the read page and I tried both settings but no difference. According to the pinouts here
http://mhv.bplaced.de/cbmroms/23256.htm
the 23 is the same as the 27 for reading since the 23 has unconnected pins on some not different ones but I don't know about pin readings the programmer would be expecting. :roll: The fact that one consistently gives five data lines as pin errors implies it might be damaged.
Can I use a 27256 window eprom that has 200nS read time or do I need a faster type?


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Ruptor
ROM Dongle
Posts: 46
Joined: Fri Dec 20, 2019 2:23 pm

Re: Hi From London England

Postby Ruptor » Tue Jan 07, 2020 12:44 pm

I found 100nS Eproms but it seems everything on the QL was designed to slow the processor down by freezing it until data is ready. I suppose it was due to the lack of technology and peripherals not able to keep up with the processor that was ahead of its time. :roll:



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