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QL Eprom Programmer

Posted: Wed Jun 14, 2017 5:00 pm
by Paul
Hello Jan,
thank you for posting the Schematic of your 1988 Eprom programmer here.
Of course a PCB can be designed and made.
If you like me to do so I will start this.
On the other hand you made the proposal to use an FPGA instead of all this chips like LSxxx and 8255.
If we go a redesign direction we should discuss our needs.
I guess a 5V tolerant CPLD like XC9572XLQVG64 that i am currently using in some other devices would be sufficient.
I need an eprom programmer for retro projects. So my need is to be able to program chips with 12,5V, 21V and even 27V VPP. Specially for those chips modern programmers don't handle anymore like 2732, 2764, 27128 etc.
I saw your design also allows for 5V and 6V VCC. I didn't know this was used somewhere but it could be added easily.

Your old design is only able to handle one chip layout.
My idea would be to be able to supply the chips with any of the required voltages at any pin via TTL compatible analog switches like 4066 or transistors like you did.
In the software I'd like to be able to select the programming sequence (I remember something like "slow", "fast", "intelligent" from old Atari ST programmers). With the possibility to add new modes.
I haven't made any QL program yet so that's where I would need assistance.

Kind regards
Paul

Re: QL Eprom Programmer

Posted: Thu Jun 15, 2017 8:36 am
by janbredenbeek
Hi Paul,
Paul wrote:Hello Jan,
thank you for posting the Schematic of your 1988 Eprom programmer here.
Of course a PCB can be designed and made.
If you like me to do so I will start this.
On the other hand you made the proposal to use an FPGA instead of all this chips like LSxxx and 8255.
If we go a redesign direction we should discuss our needs.
I guess a 5V tolerant CPLD like XC9572XLQVG64 that i am currently using in some other devices would be sufficient.

I haven't done much with electronics for the past 30 years (I studied electronics but ended up in IT). So I have no plans for making a new hardware design. Perhaps some of the hardware-oriented members here (Dave? Nasta?) have interest?
I need an eprom programmer for retro projects. So my need is to be able to program chips with 12,5V, 21V and even 27V VPP. Specially for those chips modern programmers don't handle anymore like 2732, 2764, 27128 etc.
I saw your design also allows for 5V and 6V VCC. I didn't know this was used somewhere but it could be added easily.
Your old design is only able to handle one chip layout.
My idea would be to be able to supply the chips with any of the required voltages at any pin via TTL compatible analog switches like 4066 or transistors like you did.

The 6V Vcc is used during intelligent programming. This involves applying short (1ms) programming pulses until a location has been programmed (and adding some more pulses as a safety margin).
As for the pin layout and Vpp voltage, my design assumed the 2764 was the smallest eprom in use for QL peripherals (there wasn't much point in using smaller eproms back then - the QL was designed for 16K expansion ROMs and with 8K you had plenty of address space left for I/O). I guess the inverter can also support 27V with a minor modification but the software has to be modified to support 24-pins eproms as one of the address lines is now used for Vcc.
In the software I'd like to be able to select the programming sequence (I remember something like "slow", "fast", "intelligent" from old Atari ST programmers). With the possibility to add new modes.
I haven't made any QL program yet so that's where I would need assistance.

My software supports the standard 50ms pulses and 'intelligent' using 1ms pulses. I still have the source; I'll put it on GitHub when I have time.

Jan.

Re: QL Eprom Programmer

Posted: Thu Jun 15, 2017 5:54 pm
by Dave
I'm interested, too.

I'd be happy to co-operate with anyone on this if it helps make it happen. I could have a PCB done from a schematic and ordered within a day. Paul's already expressed interest so I'll defer to him, but if you need this I can get ten made quickly. I was looking at the QEPIII a few weeks ago, but I just had more pressing things to do that day. Now, I don't.

Re: QL Eprom Programmer

Posted: Thu Jun 15, 2017 7:48 pm
by Paul
If you are interested have a go.
My main issue is that I need 27V as well and if possible the smaller pin count for 2732. I guess if it's too difficult then an adapter or second program socket would be sufficient.
i am quite busy on other projects at the moment
Kind regards Paul

Re: QL Eprom Programmer

Posted: Thu Jun 15, 2017 8:50 pm
by Dave
27V programmable devices will program correctly with 21V - using the intelligent mode it's just a little slower. Failing that, you can bump up the voltage just by adjusting a variable resistor. You can definitely program the 2732 if you just make a little adapter board.

I will be releasing a batch of prototyping boards for the QL that will be quite economical. I thought it would be fun to release a little PDF book with it with a collection of "recipes" for making things on the boards. It would include a detailed BOM, schematic, then step-by-step guide for assembling and testing your new card. It could give people a cheaper way to assemble interfaces themselves and get people experimenting.

If you're interested in having this EPROM programmer included in that library, let me know! I would do all the work - you may just get a couple of questions seeking clarification.

I'll do a separate post making a general request for schematics...