ocr: 1/O - - INPUT/OUTPUT CIRCUITS FOED OUTSCHEMATIC SHEET 1, PAGE 73, FOR EASY REFERENCE. 906108 6526 COMPLEX INTERFACE 1 VSS Ground Connection. ADAPTER 2-9 PAO-PA7 Parallel port A signals. Bidirectional parallel port. VSS- 1 40 -CNT 10-17 PBO-PB7 Parallel port B signals. Bidirectional parallel PA1 PAO- 2 3 38 39 I -SP RSO 18 PC port. after Handshake a read or output. write A on low port pulse B. is generated PA2- 4 37 ERS1 19 TOD Time of day clock input. Programmable 50hz PA3- 5 36 - RS2 or 60hz input. PA4- 6 35 I RS3 21 20 IRQ VCC 5VDC Interrupt input. output to microprocessor. PA5 7 34 33 I DBO ...
