9619_U12.pld

GAL22V10
22V10

;STANDARD PIN DEFINITION
A8  A9  A15 A10 A14 A11 A13 A12 A7  A6  A5  GND
VEC U13 U17 U20 U7  U34 U11 U10 DEC VMA VUA VCC

;MEMORY MAP
;U7 : FFE0-FFFF - ROM
;U10: FFC0-FFDF - Internal I/O
;VEC: FFC0-FFC3 - Priority Interrupt Vector Generator at U4
;DEC: FF80-FFBF - External I/O and UTIL_DECODE 
;U7 : E000-FF7F - ROM
;U13: C000-DFFF - RAM/ROM
;U17: A000-BFFF - RAM/ROM
;U34: 8000-9FFF * STANDARD 8K RAM, 0000-7FFF EXTERNAL   "32K+ ON BOARD"
;U20: 0000-7FFF * OPTION FOR 32K RAM,                   "64K ON BOARD"

;4K RAM OPTION
;U34: 8000-8FFF
;U20: 9000-9FFF


;8000-9FFF U20,U34 4K RAM OPTION
;/U20 = A15 * /A14 * /A13 *  A12
;/U34 = A15 * /A14 * /A13 * /A12
 
;8000-9FFF U34 8K RAM
/U34 = A15 * /A14 * /A13

;          U20 EMPTY (GLITCHES IF UNDEFINED)
U20 = /A15 + A15 ; 32K+ ON BOARD

;0000-7FFF U20 32K RAM (64K total) OPTION
;/U20 = /A15  ; 64K ON BOARD


;A000-BFFF  RAM/ROM
/U17 = A15 * /A14 * A13

;C000-DFFF  RAM/ROM
/U13 = A15 * A14 * /A13

;E000-FF7F,  FFE0-FFFF  ROM
/U7 = A15 * A14 * A13 * DEC * U10
 
;FF80-FFBF - External I/O
/DEC = A15 * A14 * A13 * A12 * A11 * A10 * A9 * A8 * A7 * /A6

;FFC0-FFDF - Internal I/O (except for VEC)
/U10 = A15 * A14 * A13 * A12 * A11 * A10 * A9 * A8 * A7 * A6 * /A5

;VUA/VMA OPTIONS
;CONSISTENT WITH CMS 9639 (EXT MEM IS VMA, EXT IO IS VUA ?)
;VMA = /DEC   ; 64K ON BOARD,  CMS 9639 LOGIC
;VMA = /A15   ; 32K+ ON BOARD, CMS 9639 LOGIC
;VUA = /DEC   ; CMS 9639 LOGIC

;CONSISTENT WITH CMS 9619 (VMA, VUA BOTH HI ON IO OR MEM ADDRESSES)
/VUA = DEC * A15  ; 32K+ ON BOARD, CMS 9619 LOGIC
/VMA = DEC * A15  ; 32K+ ON BOARD, CMS 9619 LOGIC
;VUA = /DEC       ; 64K ON BOARD, CMS 9619 LOGIC
;VMA = /DEC       ; 64K ON BOARD, CMS 9619 LOGIC


;EXTERNAL DATA BUS ENABLE (VEC is on the external side of U11) (HI ENABLE)
;/U11 = /VMA * /VUA * DEC * VEC   ; (U11 = VMA + /DEC + /VEC)
/U11 = A15 * DEC * VEC   ; (U11 = /A15 + /DEC + /VEC) 32K+ ON BOARD

DESCRIPTION
CMS 9619 U13 Address decoder - Reverse engineered.
Replaces PAL20L10
Set for 32K RAM + External
12-JUN-2021