Require logic array data for PALC16R4-30DMB

[Bill Hieb]

Troubleshooting board problem with PALC16R4. I have PAL program data
but no Truth Table. IF logic array data were available I could
possibly connect the dots and recover the logic.

Any help will be appreciated.

 

[Dieter Wiedmann]

Bill Hieb schrieb:

Troubleshooting board problem with PALC16R4. I have PAL program data
but no Truth Table. IF logic array data were available I could
possibly connect the dots and recover the logic.

Get the datasheet (1.3MB) here:

http://home.t-online.de/home/dieter.wiedmann/pal16.zip


Regards,
Dieter

 

[Bill Hieb]

All:

Found this article that describes how PALs are programmed. This was
very helpful to my understanding.

Sometimes the only data available are the program 1's and 0's.
(L0000, L0032, L0064... ect. for matrix width 32 lines) Using the
Logic array diagram for the Blank PAL this data can be applied to
determine the Boolean expressions.

Basically there will be a string of 1's 0's for each matrix node
point. Some of the lines will be skipped if they are not used.

10 20
L0000 1111111111111111111111111111111* ....Line 1
L0032 1111111111111111101111111111111* ....Line 2
L0064 1111111101110110111111111111111* ....Line 3
L0128 1111011111110110111111111111111* ....Line 5
..ETC
Place a dot for each 0 at the nodal point on the matrx. The first
line would not have any dots. The second line would have one dot at
node 50. Third line dots at 72, 76, and 79. The next line is skipped.
The program then picks up at line 5 node 131, 139 and 142.

The matrix will show hard wired connections to the input and output
pins. The vertical lines are usually associated with I/O. The
horizontal lines normally to logic function AND that feeds an OR into
an output or I/O function. This is obvious from the matrix diagram.

The article shows this real well.

All dots on the same horizontal line are AND inputs. Ex Line 2 node 50
1 input AND gate. Line 3 is a 3 input AND gate, Line 5 also a 3 input
AND gate. The output of each AND gate is an input to the OR gate
feeding the Output port.


If test vectors are included these are also helpful.

These are usually shown as V0001, V0002, ....etc. This will be a
string of test parameters for each pin on the chip.

V0001 C11011100N0LHXXHLHHN*
V0002 C11011110N0L LXXHLLHN*
The chip has 20 pins Vector 1 shows : P1=Clk, P2=1,P4=0,p10=N (Gnd),
P12=L (Output), P14=X (don't care) and P20=N (Vcc).


It works.

Bill

www.mactech.com/articles/mactech/Vol.01/01.11/PAL/ - 39k - Cached -
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