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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 1 | - | 1 | || FILE: #9005.PLD |
| 2 | || PROJ: 20130517 |
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| 3 | || PART: G20V8-#9005 |
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| 4 | || |
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| 5 | || DEV : GAL20V8 |
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| 6 | || |
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| 7 | || DESC: I/O DECODER & CONTROL |
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| 8 | || |
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| 9 | | |
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| 10 | |GAL20V8A |
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| 11 | | |
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| 12 | || INPUT |
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| 13 | | 1:A1, 2:A2, 3:A3, 4:A4, 5:A5, 6:A6, 7:A7, 8:IO0, 9:RW, 10:PHI2, |
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| 14 | | 11:EN, 13:RDYN, 14:RAMN, 23:-, |
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| 15 | || OUTPUT |
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| 16 | | 22:DBE, 21:VDC, 20:PIA, 19:WFF, 18:CRD, 17:CWE, 16:RD, 15:WIO |
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| 17 | | |
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| 18 | | SIGNATURE: "9005 " |
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| 19 | | |
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| 20 | | ACTIVE-LOW: DBE, VDC, PIA, WFF, CRD, CWE, RD, WIO |
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| 21 | | |
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| 22 | | PROPERTY: "SIMPLE" |
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| 23 | | |
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| 24 | || -------------------------------------------------------- |
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| 25 | || IO SELECT => FF70-FF77 (65C02) - FC70-FC77 (65C816) |
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| 26 | | IOS = (IO0' & A7' & A6 & A5 & A4 & A3') |
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| 27 | || R6545/HD6445 => FF70-FF71 / FC70-FC71 |
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| 28 | | CRTC = (IOS & A2' & A1') |
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| 29 | || REGISTRO WRITE ONLY => FF72 |
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| 30 | | WREG = (IOS & A2' & A1 & RW') |
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| 31 | || PIA 65C21 => FF74-FF77 / FC74-FC77 |
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| 32 | | PIAS = (IOS & A2) |
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| 33 | || RD => segnale OE per RAM |
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| 34 | | RD = (RW & PHI2) |
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| 35 | || CRD, CWE => segnali read,write per HD6545 (qualificati con EN) |
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| 36 | | CRD = (CRTC & RW & EN) |
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| 37 | | CWE = (CRTC & RW' & EN) |
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| 38 | || ABILITAZIONE CRTC e PIA |
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| 39 | | PIA = PIAS |
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| 40 | | VDC = CRTC |
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| 41 | || CLOCK per registro FF |
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| 42 | | WFF = (WREG & RDYN) |
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| 43 | || SEGNALE WAIT I/O |
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| 44 | | WIO = (CRTC # WREG) |
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| 45 | || SEGNALE ABILITAZIONE 74x245 |
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| 46 | | DBEIO = ((CRTC & EN) # (WREG & (EN # RDYN)) # (PIAS & PHI2)) |
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| 47 | | DBEM = RAMN' |
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| 48 | | DBE = (DBEIO # DBEM) |