The Sinclair QL Forum

Has anyone got a dissassmbly of the QEPIII ROM ? I think if we had that it might be an easier task to expand the capabilities.

I would add these as wish list items too:

1) use a different device/devices to address the I/O so that the E signal is no longer required - the 6821's used kind of force that requirement
2) Expand the available voltages - perhaps using a DAC to provide both adjustable VPP and VCC singals.
3) Support other devices besides EPROM, such as FLASH, GAL and possibly even an 8749?

All without losing the various programmging algorithms and the jiggle feature to scramble pins

I posted the sources for the Eprommer II, so sure, in principle one could extend the software for more chips. At least if they are compatible enough or an adapter board is made (like the ones used to program GALs). If it's worth the trouble is another question.

In the end it's just a matter of sending data to some special ports, this could even be made in basic if the timing allows it.

Pr0f wrote:Has anyone got a dissassmbly of the QEPIII ROM ? I think if we had that it might be an easier task to expand the capabilities.

I would add these as wish list items too:

1) use a different device/devices to address the I/O so that the E signal is no longer required - the 6821's used kind of force that requirement
2) Expand the available voltages - perhaps using a DAC to provide both adjustable VPP and VCC singals.
3) Support other devices besides EPROM, such as FLASH, GAL and possibly even an 8749?

All without losing the various programmging algorithms and the jiggle feature to scramble pins

There is a QEP v1.08 rom image on Dilwyn's site, I can disassemble this if required.

mk79 wrote:I posted the sources for the Eprommer II, so sure, in principle one could extend the software for more chips. At least if they are compatible enough or an adapter board is made (like the ones used to program GALs). If it's worth the trouble is another question.

In the end it's just a matter of sending data to some special ports, this could even be made in basic if the timing allows it.

oK, that sounds fine to me, I might just make one Eprommer II for myself.

I may have a question about the variable resistors on the board, but not yet.

Derek_Stewart wrote:oK, that sounds fine to me, I might just make one Eprommer II for myself.

I may have a question about the variable resistors on the board, but not yet.

Used to adjust the voltages. The idea is to enter test mode in the software and check the voltages using a multimeter, then adjusting the resistors for each voltage (6V, 16.5V and 12.5V). I've added the original German manual, as I don't have an English version, but might be enough to get the gist of it.

Hi Marcel,

Thanks for the information, I will translate the manual.

So the programming voltage could be altered to suit the chip being used.

Can the programming range be changed to suit the 8749 eprom area?

On assumuption that the pin connections are correct and not need a converter board.

The reasoning for using a QL, is it seems many QL users like to use QL Hardware.

Derek_Stewart wrote:So the programming voltage could be altered to suit the chip being used.

I don't think so. There are three distinct voltages and these resistors are just for fine adjustments. The software can select between these thee. But I don't understand too much about the analog part of the schematics, so they might be more variable than I know.

Can the programming range be changed to suit the 8749 eprom area?t

On assumuption that the pin connections are correct and not need a converter board.

The 8749 has much more pins than fit the socket...

Sorry, I miss understood your meaning about the voltage adjustment, all clear, now...

If I make an adpater for 40 pins could the software be altered to cope with the Eprom range of the 8749?

Derek_Stewart wrote:If I make an adpater for 40 pins could the software be altered to cope with the Eprom range of the 8749?

Not without getting some higher programming voltage >20V from somewhere, like a DC-DC converter. Apart from that it should be possible I guess. Though I personally don't think it's worth the trouble.