Dragon 32 BASIC ROMs (MCM68A364) pinout
DIP-24. Microsoft Extended Color BASIC 1.0 for the Dragon, $8000–$BFFF in two 8 KB chips.
Two 24-pin 8 KB mask ROMs hold the Dragon's BASIC, selected by the SAM device-select decode through the 74LS138 (IC33). The pinout is not the 2764 EPROM pinout: an adapter is needed to replace one with an EPROM. Dragon Data's service sheet lists IC17 and IC18 for "garbage on screen" and faults during program operation. Which chip holds $8000 and which $A000 is not marked on the SA2120 sheet.
Open the interactive BASIC ROM 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 | Q0 | data | Data output 0 (D0 on the Dragon sheet). |
| 10 | Q1 | data | Data output 1. |
| 11 | Q2 | data | Data output 2. |
| 12 | Vss | ground | Ground. |
| 13 | Q3 | data | Data output 3. |
| 14 | Q4 | data | Data output 4. |
| 15 | Q5 | data | Data output 5. |
| 16 | Q6 | data | Data output 6. |
| 17 | Q7 | data | Data output 7. |
| 18 | A11 | addr | Address bit 11. |
| 19 | A10 | addr | Address bit 10. |
| 20 | /E | ctrl | Chip enable, active LOW: E falling latches the address and enables the outputs; E HIGH deselects the chip and puts it in power-down. The data sheet prints the name without a bar; its timing is active LOW, as the Dragon sheet draws it. |
| 21 | A12 | addr | Address bit 12. |
| 22 | A9 | addr | Address bit 9. |
| 23 | A8 | addr | Address bit 8. |
| 24 | Vcc | power | +5 V supply. |
Fitted in
- Dragon 32 IC17, IC18
