TS2068 Extension ROM (2364, 28-pin) pinout
DIP-28. Extension ROM: bank switching and extra BASIC routines, Extension Bank $0000-$1FFF
An 8K x 8 mask ROM (2364) in a 28-pin package, selected by /EXROM from SCLD pin 11. It is not the 24-pin Commodore-style 2364. Pins 22, 26 and 27 are extra chip selects tied to /MREQ and /RD. A 2764 EPROM fits only after the Technical Manual rework: cut the feed to pin 27 and tie pins 1 and 27 to +5 V.
Open the interactive EXROM pinoutPins
| Pin | Name | Type | Signal |
|---|---|---|---|
| 1 | NC | nc | Not connected. Tie to +5 V when fitting a 2764 EPROM. |
| 2 | A12 | addr | Address bit 12. |
| 3 | A7 | addr | Address bit 7. |
| 4 | A6 | addr | Address bit 6. |
| 5 | A5 | addr | Address bit 5. |
| 6 | A4 | addr | Address bit 4. |
| 7 | A3 | addr | Address bit 3. |
| 8 | A2 | addr | Address bit 2. |
| 9 | A1 | addr | Address bit 1. |
| 10 | A0 | addr | Address bit 0. |
| 11 | D0 | data | Data bit 0. |
| 12 | D1 | data | Data bit 1. |
| 13 | D2 | data | Data bit 2. |
| 14 | GND | ground | Ground. |
| 15 | D3 | data | Data bit 3. |
| 16 | D4 | data | Data bit 4. |
| 17 | D5 | data | Data bit 5. |
| 18 | D6 | data | Data bit 6. |
| 19 | D7 | data | Data bit 7. |
| 20 | /CS | ctrl | Chip select from /EXROM (SCLD pin 11, P1 A27, dock pin 34). |
| 21 | A10 | addr | Address bit 10. |
| 22 | /MREQ | ctrl | Second chip select, wired to /MREQ. |
| 23 | A11 | addr | Address bit 11. |
| 24 | A9 | addr | Address bit 9. |
| 25 | A8 | addr | Address bit 8. |
| 26 | /RD | ctrl | Third chip select, wired to /RD. NC on a 2764; for a 27128 replace the /RD feed with A13. |
| 27 | /RD | ctrl | Fourth chip select, wired to /RD. /PGM on a 2764: cut the feed and tie to +5 V. |
| 28 | VCC | power | +5 V supply. |