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|| FILE: #0202.PLD|| PROJ: 20120601|| PART: G26CV12-#0202|||| DEV : GAL26CV12|||| DESC: DECODER I/O||||GAL26CV12||| INPUT| 1:A8, 2:A9, 3:A10, 4:A11, 5:A12, 6:A13, 8:A14, 9:A15, 10:A16,| 11:A17, 12:A18, 13:A19, 14:A20, 15:A21, 16:A22, 17:A23,| 27:VMA, 28:A7, 26:VDA,|| OUTPUT| 18:ME0, 19:ME1, 20:DBE, 22:DBX, 23:IO0, 24:IO1, 25:IO2|| ACTIVE-LOW: ME0, ME1, DBE, DBX, IO0, IO1, IO2||| SIGNATURE: "0202 "||| --------------------------------------------------------|||| /IO0 -> 00FC00 - 00FC7F|| /IO1 -> 00FC80 - 00FCFF|| /IO2 -> 00FD00 - 00FDFF|| /ME0 -> 100000 - EFFFFF (RAM)|| /ME1 -> 010000 - 013FFF (RAM 16K)|| /DBE -> internal data bus enable|| /DBX -> external data bus enable|||| --------------------------------------------------------||| BANK0 = (A23' & A22' & A21' & A20' & A19' & A18' & A17' & A16' & VMA')| BANK1 = (A23' & A22' & A21' & A20' & A19' & A18' & A17' & A16 & VMA')|| --------------------------------------------------------|||| IOS -> 00FC00 - 00FDFF| IOS = (BANK0 & A15 & A14 & A13 & A12 & A11 & A10 & A9' & VDA)| IO0A = (IOS & A8' & A7')| IO1A = (IOS & A8' & A7 )| IO2A = (IOS & A8)| IO0 = IO0A| IO1 = IO1A| IO2 = IO2A| CS1A = (A23' & A22' & A21' & A20' & A19 & VMA')| CSHA = (A23 & A22 & A21 & A20 & A19 & VMA')|| BANK $01 : $010000 - $01FFFF|| BANK1 = (A23' & A22' & A21' & A20' & A19' & A18' & A17' & A16 & VMA')| ME1A = (BANK1 & A15' & A14')| ME1 = ME1A|||| --------------------------------------------------------|| RAM SELECT $100000 - $EFFFFF|||| $100000 - $1FFFFF (1Mb)| BLK1 = (A23' & A22' & A21' & A20 & VMA')|| $200000 - $3FFFFF (2Mb)| BLK2 = (A23' & A22' & A21 & VMA')|| $400000 - $7FFFFF (4Mb)| BLK3 = (A23' & A22 & VMA')|| $800000 - $BFFFFF (4Mb)| BLK4 = (A23 & A22' & VMA')|| $C00000 - $DFFFFF (2Mb)| BLK5 = (A23 & A22 & A21' & VMA')|| $E00000 - $EFFFFF (1Mb)| BLK6 = (A23 & A22 & A21 & A20' & VMA')| ME0A = (BLK1 # BLK2 # BLK3 # BLK4 # BLK5 # BLK6)| ME0 = ME0A|||| --------------------------------------------------------|| INTERNAL DATA BUS ENABLE|| FIRST 16 BANKS OF RAM (1Mb), BUT NOT CX1, AND LAST 16 BANKS|| PLUS IO0|||| 16K BLOCK $014000 - $017FFF| BR1 = (BANK1 & A15' & A14)|| 32K BLOCK $018000 - $01FFFF| BR2 = (BANK1 & A15)|||| BANK $01 RAM SELECT| CS0B = (BR1 # BR2)|||| BANK $02 & $03 : $020000 - $03FFFF (128K BLOK)| CS0C = (A23' & A22' & A21' & A20' & A19' & A18' & A17 & VMA')|||| BANK $03 - $07 : $040000 - $07FFFF (256K BLOK)| CS0D = (A23' & A22' & A21' & A20' & A19' & A18 & VMA')|||| BANK $00 - $07 RAM SELECTION (512K BLOCK)| CS0A = (BANK0 # CS0B # CS0C # CS0D)|| BANKF0: $F00000 - $F7FFFF| BANKF0 = (A23 & A22 & A21 & A20 & A19' & VMA')| DBE = (CS0A # CS1A # BANKF0 # CSHA # IO0A)|||| EXTERNAL DATA BUS ENABLE||| DBX = (ME0A # ME1A # IO1A # IO2A)