MCM6810 128 x 8 static RAM pinout
DIP-24. The 256-byte CPU scratchpad at $8300: two chips, one per byte of the word.
Two 128 x 8 static RAMs make the 9900 scratchpad (decoded at $8000-$83FF, used at $8300). Each has six chip selects: CS0 and CS3 must be high, /CS1, /CS2, /CS4 and /CS5 low. +5 V only. The workspace registers live here, so a bad 6810 stops the console before the title screen.
Open the interactive MCM6810 pinoutPins
| Pin | Name | Type | Signal |
|---|---|---|---|
| 1 | GND | ground | 0 V. |
| 2 | D0 | data | Data I/O 0. |
| 3 | D1 | data | Data I/O 1. |
| 4 | D2 | data | Data I/O 2. |
| 5 | D3 | data | Data I/O 3. |
| 6 | D4 | data | Data I/O 4. |
| 7 | D5 | data | Data I/O 5. |
| 8 | D6 | data | Data I/O 6. |
| 9 | D7 | data | Data I/O 7. |
| 10 | CS0 | ctrl | Chip select 0, active high. |
| 11 | /CS1 | ctrl | Chip select 1, active low. |
| 12 | /CS2 | ctrl | Chip select 2, active low. |
| 13 | CS3 | ctrl | Chip select 3, active high. |
| 14 | /CS4 | ctrl | Chip select 4, active low. |
| 15 | /CS5 | ctrl | Chip select 5, active low. |
| 16 | R/W | ctrl | High = read, low = write. |
| 17 | A6 | addr | Address 6. |
| 18 | A5 | addr | Address 5. |
| 19 | A4 | addr | Address 4. |
| 20 | A3 | addr | Address 3. |
| 21 | A2 | addr | Address 2. |
| 22 | A1 | addr | Address 1. |
| 23 | A0 | addr | Address 0. |
| 24 | Vcc | power | +5 V supply. |