; JED2EQN -- JEDEC file to Boolean Equations disassembler (Version V063)
; Copyright (c) National Semiconductor Corporation 1990-1993
; Disassembled from J037-SEP-V1I3-U4.jed.
; Date: 2022-11-04

chip J037-SEP-V1I3-U4 PAL12L6

; J037 SEP STEbus EPROM Programmer
; IC4
; STEbus interface
;
; 2022-11-04 Read and analysed to this first draft.
; To do: compile and check the JED files match originals.
;

/BDS	=	1	; 
CM2	=	2	; 
CM1	=	3	; 
CM0	=	4	; 
A3	=	5	; 
A2	=	6	; 
A1	=	7	; 
A0	=	8	; 
T2	=	9	; 
GND	=	10	; 
/ADDR	=	11	; 
/BUF	=	13	; STEbus data buffer
/CS3	=	14	; to IC11 and IC8
/CS1	=	15	; to 8255 PIO
/WR	=	16	; to 8255 PIO
/CS2	=	17	; to DAC
/CS4	=	18	; to Status Register IC7 at xxD read
T1	=	19	; 
VCC	=	20 

;
; Intermediates
;
command_io	=	CM2 * /CM1
command_io_addr	=	command_io * ADDR
STEbus_IO	=	command_io_addr * BDS
pulse		=	T1 * /T2
read		=	CM0
write		=	/CM0
offset_PIO	=	A3 * /A2
offset_C_or_D	=	A3 * A2 * /A1
offset_C	=	A3 * A2 * /A1 * /A0
offset_D	=	A3 * A2 * /A1 * A0

equations

CS4 	=	STEbus_IO * read * offset_D
	+	command_io_addr * write * pulse * offset_C

CS2 	=	BDS * write * pulse

WR 	=	command_io_addr * write * pulse * offset_C

CS1 	=	STEbus_IO * write * pulse * offset_D

CS3 	=	STEbus_IO * offset_PIO
	+	STEbus_IO * write

BUF 	=	vcc				; check, looks iffy.
	+	vcc				; check, looks iffy.
	+	STEbus_IO * offset_PIO
	+	STEbus_IO * write