2102 static RAM 1K x 1 pinout
DIP-16. Model I video RAM: seven 2102AN-4L hold the 1 KB screen at $3C00-$3FFF.
1024 × 1 static RAM on +5 V alone, no refresh. The Model I fits seven: six hold character bits 0 to 5 and the seventh holds bit 7, the graphics flag. Bit 6 is made by NOR gate Z30 from bits 5 and 7, which is why a stock Model I has no lowercase. A bad chip puts the same wrong dot pattern or character in many screen positions, or a bit that never changes.
Open the interactive 2102 pinoutPins
| Pin | Name | Type | Signal |
|---|---|---|---|
| 1 | A6 | addr | Address bit 6. |
| 2 | A5 | addr | Address bit 5. |
| 3 | R/W | ctrl | Read/write. HIGH reads, LOW writes DATA IN while /CE is LOW. VWR* from the video multiplexer on the Model I. |
| 4 | A1 | addr | Address bit 1. |
| 5 | A2 | addr | Address bit 2. |
| 6 | A3 | addr | Address bit 3. |
| 7 | A4 | addr | Address bit 4. |
| 8 | A0 | addr | Address bit 0. |
| 9 | GND | ground | Ground. |
| 10 | Vcc | power | +5 V. |
| 11 | DATA IN | data | Data input. |
| 12 | DATA OUT | data | Data output, same polarity as the input. High impedance when /CE is HIGH. |
| 13 | /CE | ctrl | Chip enable. LOW selects the chip. |
| 14 | A9 | addr | Address bit 9. |
| 15 | A8 | addr | Address bit 8. |
| 16 | A7 | addr | Address bit 7. |
Fitted in
- TRS-80 Model I Z45-Z48, Z61-Z63