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| Rev | Author | Line No. | Line |
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| 1 | - | 1 | || FILE: #0202.PLD |
| 2 | || PROJ: 20120601 |
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| 3 | || PART: G26CV12-#0202 |
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| 4 | || |
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| 5 | || DEV : GAL26CV12 |
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| 6 | || |
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| 7 | || DESC: DECODER I/O |
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| 8 | || |
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| 9 | | |
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| 10 | |GAL26CV12 |
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| 11 | | |
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| 12 | || INPUT |
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| 13 | | 1:A8, 2:A9, 3:A10, 4:A11, 5:A12, 6:A13, 8:A14, 9:A15, 10:A16, |
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| 14 | | 11:A17, 12:A18, 13:A19, 14:A20, 15:A21, 16:A22, 17:A23, |
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| 15 | | 27:VMA, 28:A7, 26:VDA, |
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| 16 | || OUTPUT |
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| 17 | | 18:ME0, 19:ME1, 20:DBE, 22:DBX, 23:I00, 24:IO1, 25:IO2 |
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| 18 | | |
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| 19 | | ACTIVE-LOW: ME0, ME1, DBE, DBX, IO0, IO1, IO2 |
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| 20 | | |
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| 21 | | |
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| 22 | | SIGNATURE: "0202 " |
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| 23 | | |
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| 24 | || -------------------------------------------------------- |
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| 25 | || |
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| 26 | || /IO0 -> 00FC00 - 00FC7F |
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| 27 | || /IO1 -> 00FC80 - 00FCFF |
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| 28 | || /IO2 -> 00FD00 - 00FDFF |
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| 29 | || /ME0 -> 100000 - EFFFFF (RAM) |
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| 30 | || /ME1 -> 010000 - 013FFF (RAM 16K) |
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| 31 | || /DBE -> internal data bus enable |
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| 32 | || /DBX -> external data bus enable |
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| 33 | || |
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| 34 | || -------------------------------------------------------- |
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| 35 | || |
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| 36 | | BANK0 = (A23' & A22' & A21' & A20' & A19' & A18' & A17' & A16' & VMA') |
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| 37 | | BANK1 = (A23' & A22' & A21' & A20' & A19' & A18' & A17' & A16 & VMA') |
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| 38 | || -------------------------------------------------------- |
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| 39 | || |
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| 40 | || IOS -> 00FC00 - 00FDFF |
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| 41 | | IOS = (BANK0 & A15 & A14 & A13 & A12 & A11 & A10 & A9' & VDA) |
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| 42 | | IO0A = (IOS & A8' & A7') |
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| 43 | | IO1A = (IOS & A8' & A7 ) |
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| 44 | | IO2A = (IOS & A8) |
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| 45 | | IO0 = IO0A |
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| 46 | | IO1 = IO1A |
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| 47 | | IO2 = IO2A |
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| 48 | | CS1A = (A23' & A22' & A21' & A20' & A19 & VMA') |
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| 49 | | CSHA = (A23 & A22 & A21 & A20 & A19 & VMA') |
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| 50 | || BANK $01 : $010000 - $01FFFF |
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| 51 | || BANK1 = (A23' & A22' & A21' & A20' & A19' & A18' & A17' & A16 & VMA') |
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| 52 | | ME1A = (BANK1 & A15' & A14') |
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| 53 | | ME1 = CXA |
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| 54 | || |
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| 55 | || -------------------------------------------------------- |
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| 56 | || RAM SELECT $100000 - $EFFFFF |
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| 57 | || |
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| 58 | || $100000 - $1FFFFF (1Mb) |
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| 59 | | BLK1 = (A23' & A22' & A21' & A20 & VMA') |
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| 60 | || $200000 - $3FFFFF (2Mb) |
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| 61 | | BLK2 = (A23' & A22' & A21 & VMA') |
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| 62 | || $400000 - $7FFFFF (4Mb) |
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| 63 | | BLK3 = (A23' & A22 & VMA') |
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| 64 | || $800000 - $BFFFFF (4Mb) |
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| 65 | | BLK4 = (A23 & A22' & VMA') |
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| 66 | || $C00000 - $DFFFFF (2Mb) |
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| 67 | | BLK5 = (A23 & A22 & A21' & VMA') |
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| 68 | || $E00000 - $EFFFFF (1Mb) |
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| 69 | | BLK6 = (A23 & A22 & A21 & A20' & VMA') |
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| 70 | | ME0A = (BLK1 # BLK2 # BLK3 # BLK4 # BLK5 # BLK6) |
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| 71 | | ME0 = ME0A |
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| 72 | || |
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| 73 | || -------------------------------------------------------- |
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| 74 | || INTERNAL DATA BUS ENABLE |
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| 75 | || FIRST 16 BANKS OF RAM (1Mb), BUT NOT CX1, AND LAST 16 BANKS |
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| 76 | || PLUS IO0 |
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| 77 | || |
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| 78 | || 16K BLOCK $014000 - $017FFF |
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| 79 | | BR1 = (BANK1 & A15' & A14) |
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| 80 | || 32K BLOCK $018000 - $01FFFF |
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| 81 | | BR2 = (BANK1 & A15) |
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| 82 | || |
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| 83 | || BANK $01 RAM SELECT |
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| 84 | | CS0B = (BR1 # BR2) |
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| 85 | || |
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| 86 | || BANK $02 & $03 : $020000 - $03FFFF (128K BLOK) |
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| 87 | | CS0C = (A23' & A22' & A21' & A20' & A19' & A18' & A17 & VMA') |
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| 88 | || |
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| 89 | || BANK $03 - $07 : $040000 - $07FFFF (256K BLOK) |
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| 90 | | CS0D = (A23' & A22' & A21' & A20' & A19' & A18 & VMA') |
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| 91 | || |
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| 92 | || BANK $00 - $07 RAM SELECTION (512K BLOCK) |
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| 93 | | CS0A = (BANK0 # CS0B # CS0C # CS0D) |
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| 94 | || BANKF0: $F00000 - $F7FFFF |
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| 95 | | BANKF0 = (A23 & A22 & A21 & A20 & A19' & VMA') |
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| 96 | | DBE = (CS0A # CS1A # BANKF0 # CSHA # IO0A) |
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| 97 | || |
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| 98 | || EXTERNAL DATA BUS ENABLE |
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| 99 | || |
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| 100 | | DBX = (ME0A # ME1A # IO1A # IO2A) |