||	FILE:	#0053XX.PLD
||	PROJ:	20180701
||		C16 - NEW GAL FOR CPU 65C816 BOARD
||		REPLACEMENT FOR OLD GAL26CV12 CODE #0053
||
||	PART:	G26CV12-#0053XX
||
||	DEV :	GAL26CV12
||
|| 	DESC:	MASTER DECODER
||
|
|GAL26CV12
|
|| INPUT
|  1:A9, 2:A10, 3:A11, 4:A12, 5:A13, 6:A14, 8:A15, 9:A16, 10:A17, 
| 11:A18, 12:A19, 13:A20, 14:A21, 15:A22, 16:A23, 17:VMA, 18:RW,
| 24:SYS, 25:X2E, 26:RUN, 27:SEL, 28:EEN,
|| OUTPUT 
|  19:FE, 20:CS0, 22:ME, 23:EE
|
| ACTIVE-LOW: FE, ME, EE
|
| SIGNATURE: "0053XX  "
|
|| /VMA (VALID MEM. ACCESS) IS THE INVERTED (VPA OR VDA) SIGNAL
|| SYS, X2E, RUN, SEL, EEN: SIGNALS FROM CONTROL REGISTER
|| /ME (MEMORY ENABLE) SELECT SYSTEM RAM
|| /FE (FLASH ENABLE)  SELECT FLASH CHIP
|| /EE (EEROM ENABLE)  SELECT ROM EMULATOR
|| CS0 IS A PARTIAL PRODUCT TERM USED INTERNALLY
||
||
|| 	$000000 - $00FBFF MAPPING
||	---------------------------------------
||	ALWAYS MAP TO SYSTEM RAM
||
|| 	$00FC00 - $00FDFF MAPPING
||	---------------------------------------
||	ALWAYS MAP TO SYSTEM I/O
||
|| 	$00FE00 - $00FFFF MAPPING
||	---------------------------------------
|| 	SYS	RW			MAP TO:
||	0	1			FLASH
||	0	0			RAM
||	1	X			RAM
||
|| 	$010000 - $013FFF MAPPING
||	---------------------------------------
||	ALWAYS MAP TO EXPANSION RAM
||
|| 	$014000 - $01FFFF MAPPING
||	---------------------------------------
||	ALWAYS MAP TO SYSTEM RAM
||
|| 	$F00000 - $F7FFFF MAPPING
||	---------------------------------------
||	RUN	SEL	RW		MAP TO:
||	0	0	1		FLASH
||	0	1	1		EEROM
||	1	0	X		RAM
||	1	1	X		FLASH
||
|| 	$E00000 - $EFFFFF MAPPING
||	---------------------------------------
||	X2E				MAP TO:
||	0				RAM
||	1				DMA
||
|| 	$080000 - $0FFFFF MAPPING
||	---------------------------------------
||	EEN		RW		MAP TO:
||	0		X		RAM
||	1		1		EEROM
|
|
|| BANK $00 : $000000 - $00FFFF
|  BANK0 = (A23' & A22' & A21' & A20' & A19' & A18' & A17' & A16' & VMA')
||
|| $000000 - $007FFF	32K BLOCK MAPPED TO SYSTEM RAM
|  RB0 = (BANK0 & A15' )
|| $008000 - $00BFFF	16K BLOCK MAPPED TO SYSTEM RAM
|  RB1 = (BANK0 & A15  & A14' )
|| $00C000 - $00DFFF	 8K BLOCK MAPPED TO SYSTEM RAM
|  RB2 = (BANK0 & A15  & A14  & A13' )
|| $00E000 - $00EFFF	 4K BLOCK MAPPED TO SYSTEM RAM
|  RB3 = (BANK0 & A15  & A14  & A13  & A12' )
|| $00F000 - $00F7FF	 2K BLOCK MAPPED TO SYSTEM RAM
|  RB4 = (BANK0 & A15  & A14  & A13  & A12  & A11' )
|| $00F800 - $00FBFF	 1K BLOCK MAPPED TO SYSTEM RAM
|  RB5 = (BANK0 & A15  & A14  & A13  & A12  & A11  & A10')
|| $00FC00 - $00FDFF	512 BYTES BLOCK RESERVED FOR I/O
|| RB6 = (BANK0 & A15  & A14  & A13  & A12  & A11  & A10 & A9')
||
|| $00FE00 - $00FFFF	512 BYTES BLOCK MAPPED IN SYSTEM RAM OR FLASH  
|  RB7 = (BANK0 & A15  & A14  & A13  & A12  & A11  & A10 & A9)
|| RB7 MAPPED R/W TO SYSTEM RAM IF SYS=1
|  RB7R1 = RB7 & SYS
|| RB7 MAPPED WRITE ONLY TO SYSTEM RAM IF SYS=0 AND RW=0
|  RB7R2 = RB7 & SYS' & RW'
|| RB7 MAPPED READ ONLY TO FLASH IF SYS=0 AND RW=1
|  RB7F  = RB7 & SYS' & RW
||
|| BANK $00 SYSTEM RAM SELECT
|  CS0A = (RB0 # RB1 # RB2 # RB3 # RB4 # RB5 # RB7R1 # RB7R2)
||
|| BANK $01 : $010000 - $01FFFF
|  BANK1 = (A23' & A22' & A21' & A20' & A19' & A18' & A17' & A16  & VMA')
||
|| $010000 - $013FFF	16K BLOCK RESERVED FOR VIDEO RAM & I/O EXPANS. RAM
|| BR0 = (BANK1 & A15' & A14')
|| $014000 - $017FFF	16K BLOCK MAPPED TO SYSTEM RAM
|  BR1 = (BANK1 & A15' & A14)
|| $018000 - $01FFFF	32K BLOCK MAPPED TO SYSTEM RAM
|  BR2 = (BANK1 & A15)
||
|| BANK $01 SYSTEM RAM SELECT
|  CS0B = (BR1 # BR2)
||
|| BANK $02 & $03 : $020000 - $03FFFF (128K BLOCK) MAPPED TO SYSTEM RAM
|  CS0C = (A23' & A22' & A21' & A20' & A19' & A18' & A17  & VMA')
||
|| BANK $03 - $07 : $040000 - $07FFFF (256K BLOCK) MAPPED TO SYSTEM RAM
|  CS0D = (A23' & A22' & A21' & A20' & A19' & A18 & VMA')
||
|| BANK $00 - $07 SYSTEM RAM SELECTION (512K BLOCK)
|| SIGNAL CS0 IS USED INTERNALLY AND NOT USED ON EXP. BUS
|  CS0 = (CS0A # CS0B # CS0C # CS0D)
||
|| BANK $08 - $0F : $080000 - $0FFFFF  512K BLOCK
|  BK080F = (A23' & A22' & A21' & A20' & A19  & VMA')
|| BANK $08 - $0F MAPPED TO SYSTEM RAM IF EEN=0
|  BK080FR = BK080F & EEN'
|| BANK $08 - $0F MAPPED TO EEROM IF EEN=1 & RW=1
|  BK080FE = BK080F & EEN & RW
|| BANK $10 - $1F : $100000 - $1FFFFF  1MB BLOCK MAPPED TO SYSTEM RAM
|  BK101F = (A23' & A22' & A21' & A20  & VMA')
|| BANK $20 - $3F : $200000 - $3FFFFF  2MB BLOCK MAPPED TO SYSTEM RAM
|  BK203F = (A23' & A22' & A21  & VMA')
|| BANK $40 - $7F : $400000 - $7FFFFF  4MB BLOCK MAPPED TO SYSTEM RAM
|  BK407F = (A23' & A22' & VMA')
|| BANK $80 - $BF : $800000 - $BFFFFF  4MB BLOCK MAPPED TO SYSTEM RAM
|  BK80BF = (A23 & A22' & VMA')
|| BANK $C0 - $DF : $C00000 - $DFFFFF  2MB BLOCK MAPPED TO SYSTEM RAM
|  BKC0DF = (A23 & A22 & A21' & VMA')
|| BANK $E0 - $EF : $E00000 - $EFFFFF  1MB BLOCK MAPPED TO SYSTEM RAM IF X2E=0
|  BKE0EF = (A23 & A22 & A21 & A20' & VMA' & X2E')
|| BANK $F0 - $F7 : $F00000 - $F7FFFF  512K BLOCK
|  BKF0F7 = (A23 & A22 & A21 & A20 & A19' & VMA')
|| BANK $F0 - $F7 MAPPED TO SYSTEM RAM IF RUN=1 AND SEL=0
|  BKF0F7R  = BKF0F7 & RUN & SEL'
|| BANK $F0 - $F7 MAPPED R/W TO FLASH IF RUN=1 AND SEL=1
|  BKF0F7F1 = BKF0F7 & RUN & SEL
|| BANK $F0 - $F7 MAPPED READ ONLY TO FLASH IF RUN=0 AND SEL=0
|  BKF0F7F2 = BKF0F7 & RUN' & SEL' & RW
|| BANK $F0 - $F7 MAPPED READ ONLY TO EEROM IF RUN=0 AND SEL=1
|  BKF0F7E  = BKF0F7 & RUN' & SEL  & RW
|| BANK $F8 - $FF : $F80000 - $FFFFFF  512K BLOCK MAPPED TO SYSTEM RAM
|  BKF8FF = (A23 & A22 & A21 & A20 & A19  & VMA')
|
|| FINAL EQUATIONS
|| /ME SELECT SYSTEM RAM
|  MEL = (CS0 # BK080FR # BK101F # BK203F # BK407F)
|  MEH = (BK80BF # BKC0DF # BKE0EF # BKF0F7R # BKF8FF)
|  ME = MEL # MEH
|
|| /FE SELECT FLASH
|  FE = (RB7F # BKF0F7F1 #  BKF0F7F2)
|
|| /EE SELECT EEROM
|  EE = (BK080FE # BKF0F7E)