The Sinclair QL Forum

So this is a bit more of a general question (I also posted on Sinclair ZX World). I bought a TL866 II+ back in August and was able to successfully program an EPROM to work on the QL. Now I'm trying to use it to read a Hitachi HN613128P ROM chip out of my Spectrum just to verify if it's good or not. I can't find its specification in the support list. Anyone use the TL866 II+?

I think you can specify your own chips but I'm a bit too novice for that. Haven't joined a specific Spectrum forum yet but between the ZX and QL forums, hopefully someone can help. Perhaps the answer is "can't be done" but at least if I knew that I could move on to programming an EPROM and mod'ing the Spectrum to use it. But first I'd just like to know if the ROM is ok since I've tested everything else.

So I was able to read it with the Hitachi HN27256P setting but it results in a 32K image whereas it should be a 16K image. The first half of the file seems to be identical to a 16K Spectrum 48K ROM from the EightyOne emulator. Just weird that the HN27128P doesn't work.

You should be able to read it properly with the MiniPro as any generic 27128 EPROM - simply uncheck the "Check ID" checkbox before reading.

bwinkel67 wrote:So I was able to read it with the Hitachi HN27256P setting but it results in a 32K image whereas it should be a 16K image. The first half of the file seems to be identical to a 16K Spectrum 48K ROM from the EightyOne emulator. Just weird that the HN27128P doesn't work.

These mask programmable ROMs offer the ability to change the chip enable logic so they could be low or high to enable. If you look at the datasheet here
https://datasheet4u.com/datasheet-pdf/H ... ?id=755224
It says user selectable enable logic which is the problem I came across trying to read my original QL ROMs where the same chips have different enable polarity. Perhaps you can find an equivalent for the alternative polarity or as suggested above a larger EPROM that has the chip enable line as an address line that would give the block you want somewhere further up the image that you could cut and save.