1541/1571 40/42 Pin Gate Arrays Parallel/Serial Data Conversion R/W Control Logic Stepper Motor Control Spindle Motor On/Off Driver (325572) CPU Control (251828) 64H105 64H156 325572-01 251828-01(251828-02) 1541/1541A/SX-64 1541B/1541C/1541-II/1571 _____________ _____________ | |_| | | |_| | Vcc | 1 40 | B TEST | 1 40(42) |-BYTE -B | 2 39 |-BYTE YB0 | 2 39(41) | SOE -Q | 3 38 | SOE YB1 | 3 38(40) | B Q | 4 37 |-SYNC YB2 | 4 37(39) | CK -MTR | 5 36 | OE YB3 | 5 36(38) |-XQ -A | 6 35 | YB7 YB4 | 6 35(37) | Q | 7 34 | YB6 YB5 | 7 34(36) | R/W MTR | 8 33 | YB6 | 8 33(35) | LOCK | 9 32 | YB5 YB7 | 9 32(34) | PLL STP0 | 10 31 | YB4 VSS | 10 31(33) | CLR | 11 30 | YB3 STP1 | 11 30(32) | VCC STP1 | 12 29 | YB2 STP0 | 12 29(31) |-XRW | 13 28 | MTR | 13 28(30) | Y3 | 14 27 | YB1 -A | 14 27(29) | Y2 Y3 | 15 26 | YB0 DS0 | 15 26(28) | Y1 Y2 | 16 25 | Q-OUT DS1 | 16 25(27) | Y0 Y1 | 17 24 | D-IN -SYNC | 17 24(26) | ATN Y0 | 18 23 | CLK-IN TED | 18 23(25) | ATNI CLK | 19 22 | LOAD OE | 19 22(24) | ATNA Vss | 20 21 | CLR -ACCL | 20 21(23) | OSC |_____________| Vcc | (21) (22) | Vss |_____________| 1541B/1541C/1571 20 Pin Gate Array 64H157 251829-01 _________ Similar to PLS159 | |_| | Address Selector OSC | 1 20 |-RAME Saddle Canceller SYNC | 2 19 |-IO1 Motor Speed Compensator (PLL) DATA | 3 18 |-IO2 TEST | 4 17 |-CS1 Vss | 5 16 |-CS2 A15 | 6 15 | Vcc A14 | 7 14 |-ROME A13 | 8 13 | LOCK A12 | 9 12 | PLL A10 | 10 11 | CLR |_________|