1400XL PAL chips

[Shawn Jefferson]

Hi,

 

I'm on a quest to get the PAL chips I need to complete my 1450XL build, and I noticed a few interesting things and also had some questions.  I thought I'd create a new thread rather than pollute the 1450 build thread further.

 

First of all, the equations that are located here, seem to have some errors.

http://www.atarimuseum.com/archives/pdf/computers/8bits/1400-PAL_Chips-and-Equations.PDF

 

I have a PAL B (CO61917) that I ordered from Best Electronics, and was able to test it, and I noticed that VOTRAX LTCH and VOTRAX STB seem to be mixed up in the pinout in that PDF.  If you look at the speech handler document, it says that the latch is at $D104 and strobe is at $D100 (opposite of the equation document).

 

I also believe that the PAL A equations are slightly wrong (there's edits in pen on the document here and there too), but I believe that RAMINH should be set active LOW, and the equation does not show that correctly.  Also, it looks like the 1400XL PAL A is very similar to the XL/XE MMU CO61618, albeit with different pinouts.  Equations are very similar though.  I used PALASM to create a JEDEC file for PAL A, since no file has been posted by anyone else as far as I know.  I haven't had it programmed yet though, so haven't been able to verify it's correct (or that the equations are correct, but they seem fairly straight forward knowing that they are very similar to CO61618).  I did have PAL C programmed, but it appears it was not done correctly, as changing the inputs does not do anything with the outputs as it should (they all stay HIGH always, even just setting EXTSEL low, which should make PBIDEN low if I understand right, which makes me think it was not programmed correctly, or at all).  I will have to try to get those programmed again.

 

As far as testing, I built an Arduino IC tester (this one: https://github.com/akshaybaweja/Smart-IC-Tester), and also added the Arduino DRAM tester (https://atariage.com/forums/topic/289391-dramarduino-dram-tester-with-arduino/) to it (4164, 41256, 4416, and 4464), as well as added the capability to test some of these PALs, such as the CO61618 (tested several I have successfully), and the 1400XL PAL B and C.  My PAL B passes fine with the pin transcription error mentioned above.

 

On that note, does anyone have the equations for the 1200XL MMU PAL, CO60609?

 

And of course, if anyone can dump their working PAL A, that would be beneficial, although I do have (untested) equations and JEDEC file I created.  I attached those files here, but take as-is, untested.

 

 

 

 

 

1400XL-PAL-A.zip

Edited March 22, 2021 by Shawn Jefferson

[+tf_hh]

On 3/22/2021 at 11:15 PM, Shawn Jefferson said:

On that note, does anyone have the equations for the 1200XL MMU PAL, CO60609?

 

Here it is:

CHIP   MMU1200   GAL16V8   COMPLEX_MODE

A11  A12  A13  A14  A15  MAP  RD4  RD5  REN  GND
REF  S5   OSL  MPD  OSH  CI   IO   NC   S4   VCC

/S4  = /A13 & /A14 & A15 & RD4 & REF;                  /* "Right cartridge" */
/S5  =  A13 & /A14 & A15 & RD5 & REF;                  /* "Left cartridge" */

/IO  = /A11 & A12 & /A13 & A14 & A15 & REF;           /* I/O Area $D000-$D7FF */

/OSL = /A12 & /A13 &  A14 & A15 &  REN &  REF                /* O.S. Range $C000-$CFFF */
     +  A11 &  A12 & /A13 & A14 &  A15 &  MPD & REN & REF    /* Floating Point routines $D800-$DFFF */
     + /A11 &  A12 & /A13 & A14 & /A15 & /MAP & REN & REF;   /* Atari-Logo $5000-$57FF */

/OSH =  A13 &  A14 &  A15 & REN & REF;       /* O.S. Range $E000-$FFFF */

/CI  = /A13 & /A14 &  A15 & RD4 & REF        /* Set CAS Inhibit, disable DRAM when ROM */
     +  A13 & /A14 &  A15 & RD5 & REF        /* or I/O area is accessed */
     + /A11 &  A12 & /A13 & A14 & A15 & REF
     + /OSL
     + /OSH
     + /REF;

The MPD signal is connected to 5 volts via resistor, because there´s no PBI at the 1200XL. But the genuine PAL uses this signal ?

 

MMU_1200.jed

[Shawn Jefferson]

5 hours ago, tf_hh said:

 

Here it is:

CHIP   MMU1200   GAL16V8   COMPLEX_MODE

A11  A12  A13  A14  A15  MAP  RD4  RD5  REN  GND
REF  S5   OSL  MPD  OSH  CI   IO   NC   S4   VCC

/S4  = /A13 & /A14 & A15 & RD4 & REF;                  /* "Right cartridge" */
/S5  =  A13 & /A14 & A15 & RD5 & REF;                  /* "Left cartridge" */

/IO  = /A11 & A12 & /A13 & A14 & A15 & REF;           /* I/O Area $D000-$D7FF */

/OSL = /A12 & /A13 &  A14 & A15 &  REN &  REF                /* O.S. Range $C000-$CFFF */
     +  A11 &  A12 & /A13 & A14 &  A15 &  MPD & REN & REF    /* Floating Point routines $D800-$DFFF */
     + /A11 &  A12 & /A13 & A14 & /A15 & /MAP & REN & REF;   /* Atari-Logo $5000-$57FF */

/OSH =  A13 &  A14 &  A15 & REN & REF;       /* O.S. Range $E000-$FFFF */

/CI  = /A13 & /A14 &  A15 & RD4 & REF        /* Set CAS Inhibit, disable DRAM when ROM */
     +  A13 & /A14 &  A15 & RD5 & REF        /* or I/O area is accessed */
     + /A11 &  A12 & /A13 & A14 & A15 & REF
     + /OSL
     + /OSH
     + /REF;

The MPD signal is connected to 5 volts via resistor, because there´s no PBI at the 1200XL. But the genuine PAL uses this signal ?

 

MMU_1200.jed 1.07 kB · 2 downloads

Thanks!  I can add that to my chip tester now.