Chip Tester de 8bit-museum.de - Reloaded

[slabbi]

A small update:

81C54 (Siemens 512 x 8)


74C910 (64 x 4)


6561 (256 x 4)

[slabbi]

I got feedback that the 1702 adapter seems to work fine. So I published the Gerbers for it:



Please don't forget:
The chip is quite old and very special so reading this chip might not work for some reason.
The 1702A has been tested, not the 1702 (the 1702 is slower and required more current).

[papanillu]

Hi Stephan,

One question, last week, I could test some Rams and logic chips and it worked fine.
It found some bad rams, and after some tests the bad rams were allways the same, so I thing it's Ok,

Today I've just tried to test and read a ROM, and this time it didn't work.
The test was done with several 23128 from a Sinclair QL and a ZX Spectrum.
in the test, it sais that the chip was blank, and if I dump it to an SD card, i got full of FF.

any clues what should be wrong?

Thanks

[slabbi]

The 23128 ROMs can have a high or low active Chip Select.

I am currently supporting high active CS on pin 27 (23128 - 16k x 8,27=H) and low active output enable and chip enable on pin 22 and 20 like in the Commodore computers (e.g. Plus/4).

The ZX Spectrum seem to use an low active chip select. It is no problem to add a second entry with low active CS.

-- Edit
You should have received a firmware supporting a low active chip select on pin 27.

I added a new chapter for this. Hope this helps.



If a manufacturer uses a different signal level, please let me know.

[papanillu]

Hi Stephan,

With this firmware I could read the ROM perfecly.
I really didn't need to read the chip as the spectrum rom is avaiable everywhere, but it was a way to test the sd card slot.

It didn't read the QL roms, but I can imagine is because something similar to this.
If you want to experiment, I can send you a set of QL Rom,

Thanks

[slabbi]

Hi Stephan,

With this firmware I could read the ROM perfecly.
I really didn't need to read the chip as the spectrum rom is avaiable everywhere, but it was a way to test the sd card slot.

It didn't read the QL roms, but I can imagine is because something similar to this.
If you want to experiment, I can send you a set of QL Rom,

Thanks

Yes, it is one of the most used features after the memory test. Instead of guessing what is stored on an unknown EPROM you can put it in the Tester and with a little luck it says what is inside Over 2400 roms are already in the database and it can be expanded with an external file on SD card.

Sorry, that I forgot that the Speccy used an active low instead active high signal on CS. It is now part of the upcoming firmware v.14.

[slabbi]

Maybe one of the QL experts can help?

Can you confirm the active state of the CS/OE of ROMs IC33 und IC34?

I have checked the schematics how the ROMs 23256 und 23128 are addressed and my understanding is:

23256 (0000-7ffff):
Pin 20 is /CS (low active), because of A15 (A15=0 for this memory area)
Pin 22 is OE (active high) - very uncommon, only seen in QL yet

23128 (8000-bffff):
Pin 20 is CS (high active), because of A15 (A15=1 for this memory area)
Pin 22 is OE (active high) - very uncommon, only seen in QL yet
Pin 27 is /CS (low active), because of A14 (A14=0 for this memory area)

Is this correct? If so, Sir Clive has saved 2 cent for one gate and used a very uncommon low/high active combination for CS/OE.
I have to think about if it makes sense to support this because I do not expect that new ROMs will be found that must be read out...

-- Edit
I have added a sub menu that allows to select the correct H/L combination from a given set. So it is no problem to add QL support or support for other systems that uses their own combination.



Hope the QL part is correct.

[papanillu]

Hi Stephan,
after the tests, it's Ok now.
I can read & save to an sd card all the Sinclair Roms I have.

Thanks

[geloalex]

Hi Slabbi i have build mine , programmed and full working.
My board is integrated on a Sennheiser mic case , powered by two 14500 3,7 lipo battery.Main power is ON when case is opened and OFF when close it.
I leave some pics.

I will begin the chips test early .....

[slabbi]

Great idea. Looks really good.

What have you used instead of the RE-COM? Have you used SMD LEDs or 3mm ones?
It wonder how long the battery has enough power for the Tester.

From which ROM is the CRC32? Is it worth to add it in the internal database?

I have published the 0.14 beta 2. It contains several improvements acc. reading of 23xxx ROMs and you seems to be an adequate beta tester