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PAL Repository


atrax27407

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Would there be any way to set up a PAL repository for our TI gear? With aging peripherals and cards, it would be nice to have as many of the PAL JEDEC files available for repair/replacement. There are very few of them that have gotten into the "wild". Perhaps some of the electronics experts in the community could help by reverse engineering the PALs, getting the equations, and putting the resulting JEDEC files in this thread. I'm sure the community would appreciate it!

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Just for fun I created a GAL for the Rave Speech in te box. According to the file date I've done this on March the 31st in 1996.

 

Gal-Tispeech.zip

; title TI99/4A Speech in the Box
; pattern TISPEECH
; revision A
; author F. G. Kaal
; Date 960331
;
; This is a Gal for the addressing logic to place the
; TI99/4a Speech synthesizer in the expansion box.
; The three most significant addressing lines AMA,
; AMB and AMC must be High.
;
;                             A0 A1 A2 A3 A4 A5 An A15
; Speech read address  >9000   1  0  0  1  0  0  x   0    
; Speech write address >9400   1  0  0  1  0  1  x   0
;
; DBIN	- Databus in, 1= Read data, 0= Write data
; Ama	- Most significant address lines
; Amb	-  /
; Amc	- /
; A0	- Address lines to select device
; A1	-      /
; A2	-     /
; A3	-    /
; A4	-   /
; A5	-  /
; A15	- /
; RDYI	- Ready-In, Ready signal from speech synthesizer 
; RDYO	- Ready-Out, Ready to TI99/4A (open collector output)
;	  This signals will not be used, because the Speech  
;	  synthesiser is allready equiped with an open collector
;	  ready signal. If SPEECH-READY is not active, RDYI
;	  should be pulled high.
;
; RDB	- RDBENA, Low active signal to sense the selection of 
;		the speech synthesizer (open colector)
; G	- Low active signal to control the databus driver
; A15O	- Address line A15 for the speech synthesizer
; A5O	- Address line A5 for the speech synthesizer
; DIR	- Signal to control the direction of the databus driver
; SBE	- Speech Block Enable, Speech Synthesizer control signal
; LED	- Led output signal
; MEN	- Memory Enable, Low active

chip TISPEECH GAL20V8

;pin 01	  02   03   04   05   06   07   08   09   10   11   12 
     DBIN Amc  Amb  Ama  A1   A0   A3   A2   A5   A4   A15  GND
;pin 13   14   15   16   17   18   19   20   21   22   23   24
     NC   RDYI RDYO RDB  G    A15O A5O  DIR  SBE  LED  MEN  VCC   

@define Select "!MEN * Ama * Amb * Amc * A0 * !A1 * !A2 * A3 * !A4 * !A15"

equations

	SBE	= Select * !DBIN
		+ Select *  DBIN * !A5

	DIR	= DBIN
	!G	= Select * !DBIN
		+ Select *  DBIN * !A5
	!LED	= Select * !DBIN
		+ Select *  DBIN * !A5
	A5O	= A5
	A15O	= A15
	RDYO	= RDYI * SBE
	RDB	= !SBE
	RDB.trst= SBE
Edited by F.G. Kaal
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Is this one a plug-and-play replacement chip for the one already on the Rave board, Fred, or does it require a new board?

This is a plug and play replacement chip. But I see now on my RAVE board that I have connected RDYI with RDYO (pin#14 with pin #15) and these pins of the GAL are out of the IC-socket and IC-socket is destroyed at these two pins. Could be happened in the proces of why it was not working and found out after destroying the IC-socket. I see in the formulas that RDYO = RDYI * SBE. If you really wan't to know I have to check this.

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It would definitely be good to know, Fred, as that way I can do a new layout for a Speech-in-the-Box board.

Programmed a GAL20V8.

 

A have two of those RAVE 99 speech in the box cards.

 

The first one is original and tested this with the original PAL20L8 which works fine off course but with my GAL20V8 the TI system hangs.

 

The second one must have been in my Geneve system in the 90's because the 7805 voltage regulator has been removed. Also pin #14 end pin #15 of the PAL is not conected but these pins are connected together on the PCB. Tried this one on my TI99 system and there were problems, also the speech synthesizer thought so because every CALL SAY() gave me as much UHOH's as characters in the phrase.

 

Replaced the PAL20L8 by the GAL20V8 ... same result, the speech synthesizer only want to say UHOH. Then I saw that the databus buffer chip was a 74HC645 on a socket, replaced this one for a 74HCT245 and now the speech syntheziser can't stop talking (HELLO, #TEXAS INSTRUMENTS#) so I switched of the system ... my poor ears ;-)

 

Result: The above code for the GAL20v8 does work, but pin #14 and pin#15 of the GAL must be outside of the socket and these pins must be connected on the PCB.

 

This has something to do whith the RDYO and RDYI signals.

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It would definitely be good to know, Fred, as that way I can do a new layout for a Speech-in-the-Box board.

 

Pinout and formula's are in my first message.

 

The reason that I don't use the GAL20V8 to drive RDYO is that it has to be an open collector output ... I don't know how to program that (yet) for my 1990 GAL compiler.

            ___________
           |     V     |
   DBIN [ 1]           [24] Vcc
           |           |
    AMC [ 2]     G     [23] MEN
           |     A     |
    AMB [ 3]     L     [22] LED
           |           |
    AMA [ 4]     2     [21] SBE
           |     0     |
     A1 [ 5]     V     [20] DIR
           |     8     |
     A0 [ 6]           [19] A5Out
           |           |
     A3 [ 7]           [18] A15Out
           |           |
     A2 [ 8]           [17] G
           |           |
     A5 [ 9]           [16] RDBENA
           |           |
     A4 [10]           [15] RDY0 (not used)
           |           |
    A15 [11]           [14] RDYI (not used)
           |           |
    Gnd [12]           [13] NC
           |___________|

Edited by F.G. Kaal
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Did some investigation: It is unnescassery for the READY output of the speech synthesizer to go through the PAL or GAL. The speech synthesizer allready has an open collector output (transistor 2N3904) and the READY input of the console has a pullup resistor and is meant to be driven by open collecter outputs.. Have read the manual of the GAL compiler from 1991 ... no signs of any device (PAL nor GAL) that have an open collector output, it is either normal, three-state or registered. Lot of information about the speech synthesizer can be found at Thierry Nouspickel's site (off course): http://www.unige.ch/medecine/nouspikel/ti99/speech.htm

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