Atari Schematics Lost?

[Dropcheck]

1 hour ago, Dropcheck said:

These are very close to what I have traced on the bare board for the PALs.  However I am seeing on U7 PAL B pins 16 and 17 seemed to be swapped for the votrax.  On U11 PAL C pin 18 does not seemed to be connected.  I am re-verifying now.

I have re-verified the actual pinouts of all three PALs on a bare board 1450XL.  

 

PAL A U12 PAL16L8ACN matches the PAL pinout list. 

 

PAL B U7 PAL16L8ACN does not match the pinout list.  Signal trace has VOTRAXSTB on pin 16 and VOTRAXLTCH on pin 17.

 

PAL C U11 PAL16R4 does not match the pinout list.   Pin 18 does not have a trace to any part.  It is not connected.

 

So that will change the equations somewhat.  But it is very close. 

 

See page 3 of the pre-release schematic 1450XL_v1_3.pdf  attached.

 

 

1450XL_v1_3.pdf

Edited Sunday at 12:59 AM by Dropcheck

[Dropcheck]

2 hours ago, AtariGeezer said:

Here are the docs that have the Equations for PAL-A, PAL-B and PAL-C FOR THE 1400XL and should be the same for the 1450xl.

Also is a second pdf that has the Equations for the 1450xl MMU Alone...

 

Who here can create the JED files from these??? 

1400-PAL_Chips-and-Equations.pdf 1.59 MB · 1 download

CO61618A-CMOS-MMU_Chip.pdf 510.91 kB · 1 download

A question......?  This MMU is used in the 1450XL?  What is the chip designation?

[AtariGeezer]

7 minutes ago, Dropcheck said:

A question......?  This MMU is used in the 1450XL?  What is the chip designation?

 Hmmm, that could be for the TONG Version?  I have ALL 1450xl files in one folder, sorry for mixing that up...

[AtariGeezer]

38 minutes ago, Dropcheck said:

I have re-verified the actual pinouts of all three PALs on a bare board 1450XL.  

 

PAL A U12 PAL16L8ACN matches the PAL pinout list. 

 

PAL B U7 PAL16L8ACN does not match the pinout list.  Signal trace has VOTRAXSTB on pin 16 and VOTRAXLTCH on pin 17.

 

PAL C U11 PAL16R4 does not match the pinout list.   Pin 18 does not have a trace to any part.  It is not connected.

 

So that will change the equations somewhat.  But it is very close. 

 

See page 3 of the pre-release schematic 1450XL_v1_3.pdf  attached.

 

 

1450XL_v1_3.pdf 687.77 kB · 0 downloads

Looking at both of the 1400xl and 1450xl schematics, PAL C U11 Pin 18 goes to (MPE) Math Pack Enable.  I'll open up my 1450xl later tonight and verify...

[reifsnyderb]

Ok.  I found some errors in the document.  As PAL A is very similar to an 800XL MMU, I could cross reference to the 800XL MMU code.  I also double-checked the address decoding to be sure.  Here is what may work for PAL A for an ATF16V8B.

 

PALA.PLD

PALA.jed

 

[reifsnyderb]

Here is PAL B.  I swapped the VOTRAX outputs as per the schematic.

 

 PALB.PLD

PALB.jed

 

[reifsnyderb]

PAL C won't take too long.  Just let me know what the pin-outs are.  That PLD will have to be registered as there are 2 latches.  The schematic appears correct in this matter as there is a ground on the what is the output enable pin on an ATF16V8B in registered mode.

Edited Sunday at 05:20 AM by reifsnyderb

[Dropcheck]

6 hours ago, AtariGeezer said:

Looking at both of the 1400xl and 1450xl schematics, PAL C U11 Pin 18 goes to (MPE) Math Pack Enable.  I'll open up my 1450xl later tonight and verify...

The schematics in this case appear to be wrong.  Or an engineering change was made after the schematics were drawn.  I think you'll find the MPE signal goes to U8 pin 9. 

[Dropcheck]

3 hours ago, reifsnyderb said:

PAL C won't take too long.  Just let me know what the pin-outs are.  That PLD will have to be registered as there are 2 latches.  The schematic appears correct in this matter as there is a ground on the what is the output enable pin on an ATF16V8B in registered mode.

Thanks!  We'll have to wait for AtariGeezer to report back on PAL C.

 

If you are sure you can do all three with the ATF 16V8B chips, I'll make a quick mini-order to Mouser.  I don't currently have a supply.  Are they re-programmable like normal GALs?

 

 

[AtariGeezer]

1 hour ago, Dropcheck said:

The schematics in this case appear to be wrong.  Or an engineering change was made after the schematics were drawn.  I think you'll find the MPE signal goes to U8 pin 9. 

I just traced MPE going backwards from U8 Pin 9 to U11 using the hi-res board pics and you are correct (no trace on pin 18),  on the PCB it has MPE created at U11 Pin 17, but the schematic has U11 Pin 17 going to U7 Pin 7...  It's madness...  Where do you show MPE's origin signal?

 

In the mean time, this is supposed to be the correct jed for U11 PAL C (taken from the 1450xl builders thread)...

U1116R4.jed

[Dropcheck]

1 hour ago, AtariGeezer said:

I just traced MPE going backwards from U8 Pin 9 to U11 using the hi-res board pics and you are correct (no trace on pin 18),  on the PCB it has MPE created at U11 Pin 17, but the schematic has U11 Pin 17 going to U7 Pin 7...  It's madness...  Where do you show MPE's origin signal?

 

In the mean time, this is supposed to be the correct jed for U11 PAL C (taken from the 1450xl builders thread)...

U1116R4.jed 2.2 kB · 0 downloads

So far I am seeing it on R120pin1, PBI J3pin43 and the Parallel Drive Connector J12pin25.  Which makes sense since that is a signal unique to an external connection on the PBI.

 

Unfortunately that .jed is the PAL binary.  Which is fine if you have a way to buy and burn PAL chips.  Most people including me don't have the programmer necessary.  We do have the newer variety that can do GALs.  Hopefully now reifsnyderb will be able to re-create the PAL C for the Atmel ATF16V8B chip.

Edited Sunday at 10:18 AM by Dropcheck

[AtariGeezer]

Okay, I bet this will end up like the other missing trace from U8 and R134 not being tied to +5V.  Since both of the 1400xl and 1450xl schematics show U11 Pin 18 (Originating MPE signal) gong to U8 Pin 9, this look like another missing trace Atari forgot.  Getting ready for bed shortly so I'll check U8 Pin 9 for the floating 1.44 volts after I wake up.

 

I remember @Vandal968 mentioning inconsistencies between the PCB and the Schematics in the 1450xl builders thread, so this may be yet another one...

[reifsnyderb]

5 hours ago, Dropcheck said:

Thanks!  We'll have to wait for AtariGeezer to report back on PAL C.

 

If you are sure you can do all three with the ATF 16V8B chips, I'll make a quick mini-order to Mouser.  I don't currently have a supply.  Are they re-programmable like normal GALs?

 

 

 

Yes, the ATF 16V8B will do it.  It has 3 different modes of operation:  simple, complex, and registered.  It's a really nice little chip and the datasheet says it can be re-programmed 100 times.  I've probably re-programmed a single chip 20 or 30 times.

 

https://www.mouser.com/ProductDetail/Microchip-Technology/ATF16V8B-15PU?qs=2mdvTlUeTfCsdBIzx6v3gA%3D%3D

 

https://www.mouser.com/datasheet/2/268/Atmel_0364_PLD_ATF16V8B_8BQ_8BQL_Datasheet-3444797.pdf

 

 

 

 

 

 

[reifsnyderb]

3 hours ago, AtariGeezer said:

Okay, I bet this will end up like the other missing trace from U8 and R134 not being tied to +5V.  Since both of the 1400xl and 1450xl schematics show U11 Pin 18 (Originating MPE signal) gong to U8 Pin 9, this look like another missing trace Atari forgot.  Getting ready for bed shortly so I'll check U8 Pin 9 for the floating 1.44 volts after I wake up.

 

I remember @Vandal968 mentioning inconsistencies between the PCB and the Schematics in the 1450xl builders thread, so this may be yet another one...

I've ran into other places with bad Atari schematics.  For example, Atari's schematics for a 800 personality card is bad.  They corrected it later on.  I accidentally used the bad one and found out the hard way.   😞    I've also been tracing out Atari's CPS SuperSalt board and the schematics have at least one error.   😞

 

 

[+kheller2]

Shame no one has the PBI diagnostic board...  there were a few photos posted here years ago.

[+kheller2]

13 hours ago, AtariGeezer said:

 Hmmm, that could be for the TONG Version?  I have ALL 1450xl files in one folder, sorry for mixing that up...

C061618A: I'm not even sure it was for TONG as it was dated December 84.  This is CMOS version of the "stock" HAL/PAL MMU in the 600XL/800XL/XEs.

The equations should match up with previous reproductions (one would hope).

 

[reifsnyderb]

5 hours ago, AtariGeezer said:

I just traced MPE going backwards from U8 Pin 9 to U11 using the hi-res board pics and you are correct (no trace on pin 18),  on the PCB it has MPE created at U11 Pin 17, but the schematic has U11 Pin 17 going to U7 Pin 7...  It's madness...  Where do you show MPE's origin signal?

 

In the mean time, this is supposed to be the correct jed for U11 PAL C (taken from the 1450xl builders thread)...

U1116R4.jed 2.2 kB · 1 download

Worst case, the .jed file is just a fuse map.  The old datasheets had the fuse map.  So, the .jed can be reversed.   🙂

 

https://www.ti.com/lit/ds/symlink/pal16l8am.pdf?ts=1727017146727

 

There are also programs to "decompile" the fuse maps.  I'd have to locate one. 

[Dropcheck]

42 minutes ago, reifsnyderb said:

Worst case, the .jed file is just a fuse map.  The old datasheets had the fuse map.  So, the .jed can be reversed.   🙂

 

https://www.ti.com/lit/ds/symlink/pal16l8am.pdf?ts=1727017146727

 

There are also programs to "decompile" the fuse maps.  I'd have to locate one. 

I've tried paltogal.exe and a couple other dos based programs.  Not sure enough of the output, especially on the registered pal to go with it.

 

Since we have the PAL C equations already, that would probably be the best place to start converting from PAL to "GAL". 

 

If we have to, we can go back to the binary conversion process.

 

So using the pinouts in the Atari PAL equation sheet for PAL C, do you think it would be difficult to translate the PAL syntax to Atmel ATF16V8B?  Pin 18 doesn't even come into play, since no trace to any other part on the board exists.  Other circuitry appears to handle that signal.

 

ATF16V8B chips ordered.

Edited Sunday at 03:44 PM by Dropcheck

[reifsnyderb]

17 minutes ago, Dropcheck said:

I've tried paltogal.exe and a couple other dos based programs.  Not sure enough of the output, especially on the registered pal to go with it.

 

Since we have the PAL C equations already, that would probably be the best place to start converting from PAL to "GAL". 

 

If we have to, we can go back to the binary conversion process.

 

So using the pinouts in the Atari PAL equation sheet for PAL C, do you think it would be difficult to translate the PAL syntax to Atmel ATF16V8B?  Pin 18 doesn't even come into play, since no trace to any other part on the board exists.  Other circuitry appears to handle that signal.

 

ATF16V8B chips ordered.

I am looking at PAL C now.  It doesn't look bad, but the Chips and Equations document has some issues.  For example, on PAL C it's showing D1FFWR to be part of the equation for DS0 and DS1.  However, D1FFWR is really part of the clock pulse combined with the /Reset line.  So, it can't be part of the equation because the clock pulse is separate.  My thought is that whoever wrote this document wasn't familiar with how the PAL chips worked.

 

The MPE signal, on PAL C pin 18, was bothering me.  Looking at your schematic, I see how it was handled, so that's all good.  I don't need to add that as an output.  I'll make a note, on the PAL A PLD file, about it being an internal MPE signal and in no way connected to the PBI.

 

It shouldn't be long until I have a PAL C .jed file posted for you.

 

 

 

 

[reifsnyderb]

Here's PAL C

 

PALC.PLD

PALC.jed

 

Let me know if any of the PAL files need changed.  It's possible something else will turn up.

[+mytek]

8 hours ago, Dropcheck said:

If you are sure you can do all three with the ATF 16V8B chips, I'll make a quick mini-order to Mouser.

We've been using these as replacements for the very expensive Atari C101686 MMU in the 576NUC+ without issue for quite sometime now. They work great, are inexpensive, run cool, and are currently in production. No reason to use NOS GALs anymore for this kind of application. And all that talk I remembered hearing about them being too fast as compared to GALs just wasn't true.

 

Also been using it's bigger brother ATF22V10C as the EMMU in that project, and in the NUCplus4 expansion board that just got released yesterday.

[Dropcheck]

59 minutes ago, reifsnyderb said:

Here's PAL C

 

PALC.PLD 1.67 kB · 2 downloads

PALC.jed 969 B · 2 downloads

 

Let me know if any of the PAL files need changed.  It's possible something else will turn up.

Should have the chips in by Tuesday/Wednesday late.  Will report back.  Thanks! 🙂

[AtariGeezer]

6 hours ago, reifsnyderb said:

The MPE signal, on PAL C pin 18, was bothering me.  Looking at your schematic, I see how it was handled, so that's all good.  I don't need to add that as an output.  I'll make a note, on the PAL A PLD file, about it being an internal MPE signal and in no way connected to the PBI.

 

Are you confusing MPE with "NOT INTMPE"?  I haven't found the source of MPE on @Dropchecks DipTrace schematic.  Where do you see the Source of MPE being generated?

 

I believe the Atari 1450xl Schematics are mostly correct,  the 1450xl boards that were sold by Brad were probably the 2nd test run as it has missing traces...

Edited Sunday at 10:18 PM by AtariGeezer

[reifsnyderb]

12 minutes ago, AtariGeezer said:

Are you confusing MPE with "NOT INTMPE"?  I haven't found the source of MPE on @Dropchecks DipTrace schematic.  Where do you see the Source of MPE being generated?

 

I believe the Atari 1450xl Schematics are correct,  the 1450xl boards that were sold by Brad were probably the 2nd test run as it has missing traces...

PAL A, pin 14, is called MPE.  I think MPE was confused with !INTMPE in the PAL descriptions and the confusion may have been by whoever wrote that document.

 

@Dropcheck shows MPE on U8.3, pin 9.

 

 

 

 

 

 

[AtariGeezer]

1 minute ago, reifsnyderb said:

PAL A, pin 14, is called MPE.  I think MPE was confused with !INTMPE in the PAL descriptions and the confusion may have been by whoever wrote that document.

 

@Dropcheck shows MPE on U8.3, pin 9.

 

Please do a double look on that!

PAL A, pin 14, is labeled  "NOT INTMPE" which should show as an Input that is fed by U8 Pin 8.

U8 Pin 8 is where "NOT INTMPE" is generated.

U8 Pin 9 is the MPE input.

 

On both 1400xl and 1450xl schematics shows U11 Pin 18 (Originating MPE signal) gong to U8 Pin 9.

--> Both can not be wrong...