Memory
The memory I chose for my PDP-11 is a Camintonn CMV-504 dynamic RAM module. Genuine DEC memory modules, with more than 256 KB onboard, are difficult to find and much more expensive than third-party modules. Configuration information on non-DEC modules, however, can be difficult to find.
The CMV-504, shown below, packs 2 MB of RAM on a dual width board. This should be more than adequate for my needs.
The configuration information below is what I know about the dual-width Camintonn modules. It applies to the following part numbers:
- CMV-504 2 MB Memory Module
- CMV-254 1 MB Memory Module
- CMV-500 512 KB Memory Module
- CMV-250 256 KB Memory Module
Note: Most of the the jumper identifiers on the module are in very small print, making them difficult to find.
Starting Address: Jumpers 1-9, 15, 16
Update Starting Address Increment: 8K 16K 32K 64K 128K 256K 512K 1024K 2048K
| Starting Address in 512K Increments | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Address | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 15 | 16 |
| I = INSTALLED; R = REMOVED | |||||||||||
| 0 KB | I | I | I | I | I | I | I | I | I | I | R |
| 512 KB | I | I | I | I | I | I | R | R | R | R | I |
| 1024 KB | I | I | I | I | I | I | I | R | R | R | I |
| 1536 KB | I | I | I | I | I | I | R | I | R | R | I |
| 2048 KB | I | I | I | I | I | I | I | I | R | R | I |
| 2560 KB | I | I | I | I | I | I | R | R | I | R | I |
| 3072 KB | I | I | I | I | I | I | I | R | I | R | I |
| 3584 KB | I | I | I | I | I | I | R | I | I | R | I |
Ending Address: Jumpers 10-14
Update Ending Address Increment: 128K 256K 512K 1024K 2048K
| Ending Address in 512K Increments | |||||
|---|---|---|---|---|---|
| Address | 10 | 11 | 12 | 13 | 14 |
| I = INSTALLED; R = REMOVED | |||||
| 512 KB | I | I | R | R | R |
| 1024 KB | I | I | I | R | R |
| 1536 KB | I | I | R | I | R |
| 2048 KB | I | I | I | I | R |
| 2560 KB | I | I | R | R | I |
| 3072 KB | I | I | I | R | I |
| 3584 KB | I | I | R | I | I |
| 4096 KB | I | I | I | I | I |
18-bit CSR: Jumper "A" installed.
22-bit CSR: Jumper "B" installed.
CSR Parity Enabled: Jumper "C" installed.
CSR Parity Disabled: Jumper "D" installed.
| CSR Address | |||||
|---|---|---|---|---|---|
| Address | G | H | J | ||
| 17772100 | I | I | I | ||
| 17772102 | I | I | R | ||
| 17772104 | I | R | I | ||
| 17772106 | I | R | R | ||
| 17772110 | R | I | I | ||
| 17772112 | R | I | R | ||
| 17772114 | R | R | I | ||
| 17772116 | R | R | R | ||
4KW I/O Page Size: Jumper "K" installed.
2KW I/O Page Size: Jumper "L" installed.
Block Mode DMA Disabled: Jumper "S" installed.
Block Mode DMA Enabled: Jumper "T" installed.
References
- SMS 1000 Microcomputer System Models 40, 41 and 50 OEM Manual, February 1987, Scientific Micro Systems, Inc.
