Could anybody out there that remembers programming GAL's (specifically the
24 pin 22V10 variety), help me on what I'm sure is a simple problem.
I want the GAL to topple low to high on a port input. and stay high., The
next time on a port input toggle back high to low and stay low. In other
words inputting from a port toggles the output. I'm a bit limited with pins
available, only 3:-
PIN 1 NC
PIN 2 A0 ;Note these are actual S100 bus address
lines (outside the 80386)
PIN 3 A1
PIN 4 A2
PIN 5 A3
PIN 6 A4
PIN 7 A5
PIN 8 A6
PIN 9 A7
PIN 10 A8
PIN 11 A9
Pin 12 GND
Pin 13 A10
Pin 14 A11
Pin 15 A12
Pin 16 A13
Pin 17 A14
Pin 18 A15
Pin 19 sINP ;S100 bus status Port IN line
Pin 20 pDBIN ;S100 bus port read
Pin 21 TOGGLE_OUTPUT
Pin 22 NC
Pin 23 NC
;----------------------------------- Boolean Equation Segment ------
EQUATIONS
TOGGLE_OUTPUT = A0 * /A1 * A2 * A3 * /A4 * A5 * A6 *
A7 ;EDH = 1110 1101
* /A8 * /A9 * /A10 * /A11 * /A12 *
/A13 * /A14 * /A15
* sINP *
pDBIN
;Activate board with Z80 monitor QIED command
I'm assuming I need a register output, not sure what the clock should be.
Any suggestions as to a layout.
John
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