2732-pinout 4K x 8 ROM pinout
DIP-24. Character ROM in the 2732 pinout: IIe and IIc video ROM (4K x 8); PCjr character ROM (2K x 8 fitted, socket wired for a 2716 or 2732)
24-pin 4 KB ROM with the 2732 EPROM pinout: /CE on pin 18, /OE on pin 20, A11 on pin 21. A 2332 mask ROM has A11 on pin 18 and chip selects on 20 and 21, so the two do not swap without rewiring. In these machines it holds the character set, so a fault shows as wrong or broken text while graphics modes look right. A 2732 EPROM is a direct replacement. PCjr: the fitted character generator holds 2K bytes (MCM68A316E or equivalent), and IBM says the device is pin compatible with 2716 and 2732 EPROMs (Technical Reference p. 2-49). Jumper W2 puts +5 V or RA3 on pin 21 (sheet 5 of 17), so the socket also takes a 4 KB part.
Open the interactive 2732 pinoutPins
| Pin | Name | Type | Signal |
|---|---|---|---|
| 1 | A7 | addr | Address bit 7. |
| 2 | A6 | addr | Address bit 6. |
| 3 | A5 | addr | Address bit 5. |
| 4 | A4 | addr | Address bit 4. |
| 5 | A3 | addr | Address bit 3. |
| 6 | A2 | addr | Address bit 2. |
| 7 | A1 | addr | Address bit 1. |
| 8 | A0 | addr | Address bit 0. |
| 9 | D0 | data | Data bit 0. |
| 10 | D1 | data | Data bit 1. |
| 11 | D2 | data | Data bit 2. |
| 12 | GND | ground | Ground. |
| 13 | D3 | data | Data bit 3. |
| 14 | D4 | data | Data bit 4. |
| 15 | D5 | data | Data bit 5. |
| 16 | D6 | data | Data bit 6. |
| 17 | D7 | data | Data bit 7. |
| 18 | /CE | ctrl | Chip enable, active LOW. |
| 19 | A10 | addr | Address bit 10. |
| 20 | /OE | ctrl | Output enable, active LOW. |
| 21 | A11 | addr | Address bit 11. On the PCjr, jumper W2 connects it to +5 V or to RA3 (sheet 5 of 17); a 2K part has no A11. |
| 22 | A9 | addr | Address bit 9. |
| 23 | A8 | addr | Address bit 8. |
| 24 | VCC | power | +5 V supply. |
Fitted in
- Apple IIe UF4, video ROM: 342-0133 (unenhanced) or 342-0265 (enhanced). Apple schematic 050-0051-D sheet 3 draws a 2732.
- Apple IIc UE4, marked CHAR GEN: 342-0265-A on the photographed board. Schematic 050-0093-A sheet 2/5 draws a 28-pin 2732/2764 site with 2764 pin numbers, so add 2 to the pin numbers below.
- IBM PCjr 4860 ZM64, character ROM (IBM 1503723 on the photographed board). PCjr Technical Reference, sheet 5 of 17, draws an MK34000.
Sources
- IBM PCjr Technical Reference (Nov 1983), System Board sheet 5 of 17, p. B-7: ZM64 MK34000, all 24 pins
- IBM PCjr Technical Reference (Nov 1983), Video Subsystem, Character Generator: 2K bytes, MCM68A316E or equivalent, pin compatible with 2716 and 2732, p. 2-49
- Apple IIe schematic 050-0051-D, sheet 3 of 4: UF4 2732 video ROM (PDF p. 4)