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Willem programmers and reading late seventies vintage masked ROMS

MikeS said:
Umm, yeah, isn't that pretty well what Dave suggested, although of course from the other perspective, i.e. replacing your ROM with a 2716?
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Sure, it's just that Pete and Dwight gave explicit wiring instructions on making an adapter to read the mask ROM in the Willem programmer which is why I mentioned them. That's not discounting Dave's excellent contribution to the eventual ROM replacement or indeed your own.

Tez
 
tezza said:
That's great. Thanks. I'll digest this and see what I can do.
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OK, I think Anders pointed out an adapter by Pet Rescue that may be more complicated than you need. It is for programming a 2532 into a programmer set for a 2732. However, the beauty of this adapter is that you only have to build one of them assuming your Willem can program the ORIGINAL NMOS 25V 2732 (not just the 12V 27C32).

You were asking for an adapter to use a 2732 in a PET ROM socket. All you need for that is an adapter that is connects all pins one to one except for pins 18 and 21 which shall not be connected to their counterpart pins.

Connect pin 18 of ROM socket to pin 21 of the 2732 (A11).
Leave pin 21 of the ROM socket unconnected to the 2732 (+5V)
Jumper the 2732 pins 18 and 20 together (/CE). Note these pins will also connect to pin 20 of the ROM socket.

This type adapter would be needed in all 4K ROM sockets. For the 2K "E000" socket, a 2716 can be used without any adapter.
 
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dave_m said:
You were asking for an adapter to use a 2732 in a PET ROM socket. All you need for that is an adapter that is connects all pins one to one except for pins 18 and 21 which shall not be connected to their counterpart pins.

Connect pin 18 of ROM socket to pin 21 of the 2732 (A11).
Leave pin 21 of the ROM socket unconnected to the 2732 (+5V)
Jumper the 2732 pins 18 and 20 together (/CE). Note these pins will also connect to pin 20 of the ROM socket.

This type adapter would be needed in all 4K ROM sockets. For the 2K "E000" socket, a 2716 can be used without any adapter.
Click to expand...

Dave, that's just the information I was looking for. Thanks for outlining it so clearly. I'm assuming that both 2732 and 27C32 will work in these adaptors, yes?

Tez
 
tezza said:
Sure, it's just that Pete and Dwight gave explicit wiring instructions on making an adapter to read the mask ROM in the Willem programmer which is why I mentioned them. That's not discounting Dave's excellent contribution to the eventual ROM replacement or indeed your own.

Tez
Click to expand...
Yeah, re-reading I suppose it wasn't as clear as it could be that it's really the same adapter; when you want to read your ROM in the Willem you connect pin 21 to ground, and when you want to use the 2716 in the ROMpack you connect pin 21 to Vcc.
 
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tezza said:
Dave, that's just the information I was looking for. Thanks for outlining it so clearly. I'm assuming that both 2732 and 27C32 will work in these adaptors, yes?

Tez
Click to expand...
Now I'm confused again; I thought you asked about reading the PET ROMs, which this will not do; also, if you're going to replace the ROMs with 2732s containing BASIC 4, as Dave points out you will need four of these adapters in the PET whereas if you use the compatible 2532s you'll only need one for the Willem to program them (which may come in handy for another future system that uses 2532-compatible ROMs).
 
At the moment, I just want to replace two of the BASIC 4 ROMS which are faulty. I already know they are faulty.

I may have misinterpred Dave's text. Would I need to replace ALL the ROMS (including the existing good ones) with 2732s and the adaptors? I read it to mean that all 4 BASIC ROM chips would need the adaptor ONLY IF THEY WERE REPLACED, not that ALL the BASIC ROM would NEED to be replaced as a bank (even if only one is faulty)? If I need to build 4 adaptors then this puts a different light on it.

I can see the advantaqe of having an adaptor which will program 2532s. It's tempting to build two PET ROM adaptors first though, as I have access to some 2732 eproms close by.

However, I can still weigh up options. I haven't read the details of the info Anders pointed me to yet, so I don't know how complex the task is. Also I haven't checked out how accessible 2532s might be for me. This, and whether I need just 2 adaptors or 4 will all have a bearing on what's decided. Also it doesn't need to be mutually exclusive. Sockets and EPROMS aren't that expensive so I might do a quick fix first, then make a 2532 Willem adaptor later.

No real hurry. I want to clear this Sorcerer issue first (and write it up). It will be then time to revist the PET while I have the Willem out.

Tez
 
tezza said:
At the moment, I just want to replace two of the BASIC 4 ROMS which are faulty. I already know they are faulty.
Click to expand...

The simple adapter can be used as needed, one socket at a time.

The 2732 or 27C32 should be fine. Although get the fastest 27C32's you can find (250 nS?) as it may not like the capacitance load of all the old NMOS devices on the PET bus.

When you get a chance, find out if your model Willem can handle the plain "2732". If it lists only 2732A, 2732B, 27C32, etc, then you will not be able to program the 2532 even with PET Rescue's adapter.
-Dave
 
tezza said:
I may have misinterpred Dave's text. Would I need to replace ALL the ROMS (including the existing good ones) with 2732s and the adaptors?
Click to expand...
Sorry, my misunderstanding; I thought you were upgrading from BASIC 2 at the same time, but now I see that when you were talking about "upgrading to 4.0" you meant upgrading the other PET with another complete PET ;-) ; no, you'd only need an adapter for any ROMs that you're replacing with 2732s.
 
MikeS said:
Sorry, my misunderstanding; I thought you were upgrading from BASIC 2 at the same time, but now I see that you were talking about upgrading the other PET with another complete PET ;-) ; no, you'd only need an adapter for any ROMs that you're replacing with 2732s.
Click to expand...

Yes, I've got two PET boards. One with all good BASIC 2.0 ROMS, and the other board with a set of 4.0 ROMS...but two of those ROMS are knackered.

Tez
 
dave_m said:
When you get a chance, find out if your model Willem can handle the plain "2732". If it lists only 2732A, 2732B, 27C32, etc, then you will not be able to program the 2532 even with PET Rescue's adapter.
Click to expand...

Thanks Dave I'll check.

I'm still getting my head around the huge variety of chip types available for programming and exactly what the differences are.

Tez
 
tezza said:
Thanks Dave I'll check.

I'm still getting my head around the huge variety of chip types available for programming and exactly what the differences are.

Tez
Click to expand...
Well, talking only about eraseable EPROMs (as opposed to oxymoronic OTP EPROMs that are not in fact eraseable ;-) ): size, speed, pinout, supply voltage(s), programming voltage, programming algorithm, standby current, special read timing requirements, just to get you started ;-)

Keep some Aspirin close to hand...
 
I've had a look at Pet Rescue's adapter. It doesn't look too hard at all.

dave_m said:
When you get a chance, find out if your model Willem can handle the plain "2732". If it lists only 2732A, 2732B, 27C32, etc, then you will not be able to program the 2532 even with PET Rescue's adapter.
Click to expand...

I'll check tonight. What do the suffix letters actually relate to?

The difficulty with this route will be getting hold of a couple of 2532s. Any one know a cheap source? Arcadecomponents list them but I'm not sure if the shop is open. I see some on e-bay. Do the suffixes JL or JDL mean non-compatibility like the A, B, C etc.?

Of course it all may be academic if my Willem doesn't do straight 2732s

Tez
 
tezza said:
What do the suffix letters actually relate to?

The difficulty with this route will be getting hold of a couple of 2532s. Any one know a cheap source? Arcadecomponents list them but I'm not sure if the shop is open. I see some on e-bay. Do the suffixes JL or JDL mean non-compatibility like the A, B, C etc.?
Click to expand...

I think MikeS gave a description of EPROM types a while ago. They mostly have to do with programming voltages and speed (access time). The 2732 and 2532 have a Vpp of 25V which is what the new programming gadgets generally can not handle.

The "A" usually means a 21V programming voltage (Vpp) and CMOS devices like the 27C32 usually have a Vpp of 12.5V.

Parts that end with a -35 may mean a 350 nS access time, etc.

The fellow at Arcade Components (Ray?) come into a stash of many hundreds of 2532s but he has been hard to get a hold of as he had been busy with his day job.

Most 2532 EPROMs are from Texas Instruments and the full part numbers you want are: TMS2532-30 JL, TMS2532-35 JL, and TMS2532-45 JL in order of speed.

Any 2532 will work in a PET as it was designed for the slowest. The JL simply means 24 pin ceramic Dual In-line Package (DIP). I don't know the JDL type but it is probably OK.

National Semiconductor and others second-sourced the parts, but I am not as familiar with their full part numbers.
 
Futurlec has the 27C32 EPROMs new. +5 Vcc; 12.5 Vpp; about $5 each. They also have the ST M2732 NMOS parts (+5 Vcc; 21 Vpp).

They're in Thailand, so not on the other side of the world from you.
 
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Chuck, Dave, Thanks for the info,

It seems my Willem can handle plain old 2732's. There is also a jumper which puts the voltage up to 25V for that purpose.

Tez
 
This evening I made an 2732 --> 2532 adapter as per Pet Rescue. It worked!!

I was able to read my PET's "spare board" BASIC 4.0 ROM Chips. Comparing the read with the ROM binaries on the Net it verifed my "number-8-wire" findings ie. that both the B000-BFFF chip and the Kernal was bad.

Now I just have to wait for my 2532 compatible ICs to arrive to burn replacements. Hopefully that process will go as smoothly as everything else has up to now.

Tez
 
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