LSI-11 Processors
Overview
The LSI-11 processor is a microcomputer that was originally designed for OEM use, and meant to be integrated in third-party products. It was later packaged and sold by DEC as the PDP-11/03 line of production computers.
The processor has a 16-bit address bus and a 16-bit data bus. It can address up to 64 KB (32 KW) of memory and reserves the top 8 KB (4 KW) of the address space for I/O devices. This leaves up to 56 KB (28 KW) of memory for programs and data. Some configurations allow the I/O area to be reduce to 4 KB, allowing up to 60 KB (30 KW) of memory for programs.
In the table below, I broke out each processor by model number to illustrate the base variations. I many cases, the variation between two models was simply the addition of a chip, or chipset. For instance, adding an EIS/FIS chip to a KD11-F processor changes its model number to KD11-L.
| LSI-11 Processors and Their Capabilities | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Processor | LSI-11 | LSI-11/2 | ||||||||
| Module Number | M7264 | M7264-BB | M7264-YA | M7264-YB |
M7264-YC |
M7270 | ||||
| Model Number | KD11-F | KD11-L | KD11-P | KD11-H | KD11-N | KD11-Q | KD11-H | KD11-N | KD11-HA | KD11-NA |
| Component Side |
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| Solder Side |
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| Introduced | 1975 | 1975 | 1977 | 1976 | 1976 | 1977 | 1980 | 1980 | 1977 | 1977 |
| Discontinued | 1977 | 1977 | 1984 | 1980 | 1980 | 1982 | ||||
| Module Size | Quad | Quad | Quad | Quad | Quad | Quad | Quad | Quad | Dual | Dual |
| Chipset | LSI-11 | LSI-11 | LSI-11 | LSI-11 | LSI-11 | LSI-11 | LSI-11 | LSI-11 | LSI-11 | LSI-11 |
| DIS Instructions | optional1,3 | no2 | yes | optional1,3 | no2 | yes | optional1,3 | yes | optional1,2 | no2 |
| EIS Instructions | optional5 | yes | yes | optional5 | yes | yes | optional5 | yes | optional4 | yes |
| FIS Instructions | optional6 | yes | no | optional6 | yes | no | optional6 | no | optional4 | yes |
| Memory Management | no | no | no | no | no | no | no | no | no | no |
| Performance (VUP) | 0.05 | 0.05 | 0.05 | 0.05 | 0.05 | 0.05 | 0.05 | 0.05 | 0.05 | 0.05 |
| Clock Period (ns)7 | 360-4008 | 360-4008 | 360-4008 | 360-4008 | 360-4008 | 360-4008 | 360-4008 | 360-4008 | 380 | 380 |
| Q-bus Address Size | 16-bits | 16-bits | 16-bits | 16-bits | 16-bits | 16-bits | 16-bits | 16-bits | 16-bits | 16-bits |
| Q-bus Interrupts | 1-level | 1-level | 1-level | 1-level | 1-level | 1-level | 1-level | 1-level | 1-level | 1-level |
| RAM Capacity | 64 KB | 64 KB | 64 KB | 64 KB | 64 KB | 64 KB | 64 KB | 64 KB | 64 KB | 64 KB |
| Onboard RAM | 8 KB | 8 KB | 8 KB | no | no | no | no | no | no | no |
| Onboard ROM | no | no | no | no | no | no | no | no | no | no |
| ODT Microcode | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| Memory Refresh | yes | yes | no9,10 | yes | yes | no9 | yes | yes | no | no |
| Termination (ohms) | 250 | 250 | 250 | 250 | 250 | 250 | 250 | 250 | 220 | 220 |
| AC Bus Load | 2.4 | 2.4 | 2.4 | 2.4 | 2.4 | 2.4 | 2.4 | 2.4 | 1.7 | 1.7 |
| DC Bus Load | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| +5V Load | 1.8 A | 1.8 A | 1.8 A | 1.8 A | 1.8 A | 1.8 A | 1.8 A | 1.8 A | 1.2 A | 1.2 A |
| +12V Load | 0.8 A | 0.8 A | 0.8 A | 0.8 A | 0.8 A | 0.8 A | 0.8 A | 0.8 A | 0.22 A | 0.22 A |
1
Requires the KEV11-CA 23-004B5 & 23-005B5 DIBOL chip set.
2
The DIS and EIS/FIS chipsets are mutually exclusive.
3
Requires etch Rev E or F.
4
Requires the KEV11-A (23-003B5) EIS/FIS processor chip.
5
Etch Rev C requires the KEV11 23-091A5-01 EIS/FIS processor chip.
Etch Rev D requires the KEV11 23-091A5-01 EIS/FIS processor chip,
or the KEV11-B 12-090A5-01 EIS-only processor chip.
Etch Revs E & F require the KEV11-A 23-003B5 EIS/FIS processor chip.
6
Etch Revs C & D require the KEV11 23-091A5-01 EIS/FIS processor chip.
Etch Revs E & F require the KEV11-A 23-003B5 EIS/FIS processor chip.
7
Clock frequency = 1 / Clock Period (e.g. 1 / 400 ns = 1 / 0.0000004 = 2,500,000 Hz, or 2.5 MHz)
8
Module has a variable frequency oscillator, so the period may vary
slightly.
9
The DIBOL chipset does not have microcode refresh.
10
A system must be equipped with an REV11 module to perform the onboard
memory refresh operation.
Due to the number of variations in M7264 module numbers, referenced in the DEC documentation, I went ahead and broke out the differences between them. Most have to do with the RAM chip manufacturer used.
| M7264 variations | |
|---|---|
| Variation | Description |
| M7264 | Processor with 350ns Mostek 4096 RAM |
| M7264-AA | M7264 or M7264-AB, CB, DB, EB, FB, HB, JB |
| M7264-AB | Processor with 350ns Intel 2104 RAM |
| M7264-BB | Processor with 350ns Mostek 4096 RAM and DIBOL microm |
| M7264-CB | Processor with 350ns Fujitsu 8224 RAM |
| M7264-DB | Processor with 350ns Intel 2104A RAM |
| M7264-EB | Processor with 200ns Mostek 2047 RAM |
| M7264-FB | Processor with 200ns DEC 2047 RAM |
| M7264-HB | Processor with 200ns Motorola 2047 RAM |
| M7264-JB | Processor with 200ns Fujitsu 8227 RAM |
| M7264-YA | Processor with no onboard RAM |
| M7264-YB | Processor with no onboard RAM and DIBOL microm |
| M7264-YC | Processor with no onboard RAM (replaced the M7264-YA) |
I also broke down the more common KD11 variations, to clarify their differences.
| Q-bus KD11 Variations | |
|---|---|
| Variation | Description |
| KD11-F | LSI-11 processor, 4KW MOS RAM onboard |
| KD11-H | LSI-11 processor, no onboard RAM |
| KD11-J | KD11-H packaged with a MMV11-A 4KW core memory module |
| KD11-L | KD11-F with EIS/FIS |
| KD11-M | KD11-J with EIS/FIS |
| KD11-N | KD11-H with EIS/FIS |
| KD11-P | LSI-11 processor with DIBOL microm, 4KW MOS RAM onboard |
| KD11-Q | LSI-11 processor with DIBOL microm, no onboard RAM |
| KD11-R | KD11-H packaged with a MSV11-CD 16KW MOS memory module |
| KD11-S | KD11-R with EIS/FIS |
| KD11-U | KD11-H packaged with an MRV11-BA EPROM module |
| KD11-HA | LSI-11/2 processor |
| KD11-NA | LSI-11/2 processor with EIS/FIS |
Summary
Probably the more desirable processor to own is the M7270 LSI-11/2. It has all of the relevant capabilities that the larger M7264 has, but takes up less space in the card cage. It is fairly common and affordable.
An early KD11-F, or KD11-J, with a core memory board would also be desirable, for historical preservation purposes. An M7264 with the DIBOL (commercial) instruction set would be collectable, due to its rarity.
References
- LSI-11, PDP-11/03 User's Manual, 2nd Edition, November 1975 (EK-LSI11-TM-002)
- LSI-11, PDP-11/03 User's Manual, 3nd Edition, May 1976 (EK-LSI11-TM-003)
- M7270 LSI-11/2 Microcomputer Module User's Guide
- LSI-11 Systems Service Manual, 3rd Edition, August 1981 (EK-LSIFS-SV-003)
- LSI-11 Systems Service Manual, 5th Edition, January 1985 (EK-LSIFS-SV-005)
- KD11-F Field Maintenance Print Set, Revision A, January 1978 (MP00049)
- KD11-H Field Maintenance Print Set, Revision A, January 1978 (MP00050)
- KD11-J Field Maintenance Print Set, Revision B, September 1975 (MP00051)
- KD11-M Field Maintenance Print Set, Revision B, May 1976 (MP00053)
- Digital Equipment Corporation Option/Module List, June 23, 1975
- Digital Equipment Corporation Option/Module List, December 3, 1975
- Digital Equipment Corporation Option/Module List, April 21, 1983
Additional Resources
- MicroNote 5 - Q22 Compatible Options
