name: MCS6520 function: Peripheral Interface Adaptor package: 40pin DIP,40 manufacturer: Synertek added-by: Gary Walker +--()--+ Vss | 1 40| CA1 PA0 | 2 39| CA2 PA1 | 3 38| /IRQA PA2 | 4 37| /IRQB PA3 | 5 36| RS0 PA4 | 6 35| RS1 PA5 | 7 34| /RES PA6 | 8 33| D0 PA7 | 9 32| D1 PB0 |10 31| D2 PB1 |11 30| D3 PB2 |12 29| D4 PB3 |13 28| D5 PB4 |14 27| D6 PB5 |15 26| D7 PB6 |16 25| ENABLE PB7 |17 24| CS2 CB1 |18 23| /CS3 CB2 |19 22| CS1 Vcc |20 21| R/W +------+ This information was added by a third party and may be incorrect. This pinout came from the Chipdir: http://www.chipdir.org/