; JED2EQN -- JEDEC file to Boolean Equations disassembler (Version V063)
; Copyright (c) National Semiconductor Corporation 1990-1993
; Disassembled from J121-iss1.JED. Date: 2022-04-07
; Labelled SEMC iss 1 416 561119 MMI 16L8
chip J121-iss1 PAL16L8

A3		= 1 
A2		= 2 
A1		= 3 
A0		= 4 
CM0		= 5 
CM1		= 6 
CM2		= 7 
/DATSTB		= 8 
START		= 9	; U (LS164) pin 4 ()
GND		= 10 
END		= 11	; U (LS164) pin 12 ()
/RD_PORT_IN	= 12	; U20
/BUSEN		= 13 
/unused		= 14	; U10 (LS126) pin 6 (out) and 4k7 pull-up above U5
			; U10 (LS126) pin 5 (in) is 0V, pin 4 (EN) is from U7 pin 6 (out)
			; U7 pin 5 (in) is from link  to an RC network, perhaps an RC reset?
/PEQ		= 15	; low if /ADRSTB active and the address matches the links.
/RD_RESPONSE	= 16 	; U8 pin 1
/RD_STATUS	= 17	; U9 pin 1
/WR_COMMAND	= 18 	; U11 pin 11
/WR_PORT_OUT	= 19 	; U23 pin 11 
VCC		= 20 

equations

base		=	PEQ * CM2 * /CM1 * /DATSTB * A3 * A2

offset_0	= 	/A1 * /A0
offset_1	= 	/A1 *  A0
offset_2	= 	 A1 * /A0

offset_0_or_1	=	/A1

read		=	CM0
write		=	/CM0
pulse		=	START * /END

WR_COMMAND	= base * offset_0 * write * pulse
RD_RESPONSE	= base * offset_0 * read

RD_STATUS	= base * offset_1 * read 

WR_PORT_OUT	= base * offset_2 * write * pulse
RD_PORT_IN	= base * offset_2 * read


BUSEN		= base * offset_0_or_1
		+ base * offset_2 * 

unused		= vcc		; always true so pin always low


/RD_RESPONSE.oe	= vcc
/WR_COMMAND.oe	= vcc
/RD_STATUS.oe	= vcc
/unused.oe	= vcc
/BUSEN.oe	= vcc
/RD_PORT_IN.oe	= vcc
/WR_PORT_OUT.oe	= vcc