| Pin Number |
Pin Name |
Description (may be empty) |
| 1 | +5V | -> |
| 2 | +5V | -> |
| 3 | GND | |
| 4 | GND | |
| 5 | XDRD0 | <-> memory expansion data word |
| 6 | XDRD1 | |
| 7 | XDRD2 | |
| 8 | XDRD3 | |
| 9 | XDRD4 | |
| 10 | XDRD5 | |
| 11 | XDRD6 | |
| 12 | XDRD7 | |
| 13 | XDRD8 | |
| 14 | XDRD9 | |
| 15 | XDRD10 | |
| 16 | XDRD11 | |
| 17 | XDRD12 | |
| 18 | XDRD13 | |
| 19 | XDRD14 | |
| 20 | XDRD15 | |
| 21 | GND | |
| 22 | GND | |
| 23 | A8 | -> address lines |
| 24 | A7 | |
| 25 | A6 | |
| 26 | A5 | |
| 27 | A4 | |
| 28 | A3 | |
| 29 | A2 | |
| 30 | A1 | |
| 31 | A0 | |
| 32 | ~EXRAM | <- to activate mem expansion, connect to GND |
| 33 | GND | |
| 34 | GND | |
| 35 | ~CASL | -> ~CAS for the low byte |
| 36 | ~CASH | -> ~CAS for the high byte |
| 37 | ~RAS0 | -> (by default used by internal mem -- depends on JP3) |
| 38 | ~RAS1 | -> ~RAS for external memory -- depends on JP3 |
| 39 | ~WE | -> write enable |
| 40 | ~CCK | -> (some clock signal...not used by standard memory expanders) |
| 41 | XD0 | <-> data lines to real-time clock ( M6242B ) |
| 42 | XD1 | |
| 43 | XD2 | |
| 44 | XD3 | |
| 45 | XA0 | -> addres lines to real-time clock |
| 46 | XA1 | |
| 47 | XA2 | |
| 48 | XA3 | |
| 49 | ~XCLKRD | -> external clock read (read date/time) |
| 50 | ~XCLKWR | -> external clock write (set date/time) |
| 51 | +5V | -> |
| 52 | +5V | -> |
| 53 | GND | |
| 54 | GND | |
| 55 | +12V | -> |
| 56 | -12V | -> |
(Directions relative to computer.)
You can also identify the pins on the expansion board by holding it with components up and the connector at the right side: pin 1 - top left, pin 2 top right...
correct
incorrect