View source for LSI-11

The '''LSI-11''' was DEC's first cost-reduced [[PDP-11]] [[Central Processing Unit|CPU]], using the [[QBUS]] and the [[LSI-11 chip set]]. It was the first of the [[LSI-11 CPUs]]; it had the [[QBUS]] limitations, and use of [[QBUS CPU ODT|ODT]] for control, as the others.

The LSI-11 is a [[DEC card form factor|quad]] board (M7264) with additional functionality on-board. They were popular in [[Original Equipment Manufacturer|OEM]] usage.

The usual CPU options were available for the LSI-11: the [[KEV11-A floating point|KEV11-A]], for the [[PDP-11 Extended Instruction Set|EIS]]/[[FIS floating point|FIS]] instructions; the [[KEV11-B Extended Instruction Set|KEV11-B]] provides EIS without FIS; the [[KEV11-C Commercial Instruction Set|KEV11-C]] provides a subset of the PDP-11 [[PDP-11 Commercial Instruction Set|CIS]] (it also apparently includes the EIS, but not the FIS).

The [[integrated circuit|chip]] order (from the left, with the contact finger edge down, and the component side facing the viewer) is [[KEV11]], uROM 1, uROM 0, Control, Data Path.

==Variant models==

Many different LSI-11 models exist, including the '''KD11-F''' and '''KD11-H''' base versions, and numerous other variants. The KD11-F version includes 4KW of [[Metal Oxide Semiconductor|MOS]] [[Random Access Memory|RAM]] on-board; the KD11-H version has the RAM deleted.

Others included various KEV11 chips pre-installed:

* the KD11-L is a KD11-F with a KEV11-A
* the KD11-N is a KD11-H with a KEV11-A
* the KD11-P is a KD11-F with a KEV11-C
* the KD11-Q is a KD11-H with a KEV11-C

Some models include additional cards: 

* the KD11-J is a KD11-H sold with an [[MMV11-A QBUS core memory]] card
* the KD11-R is a KD11-H sold with an [[MSV11-C QBUS MOS memory]] card

==See also==

* [[LSI-11/2]]

==External links==

* [http://web.frainresearch.org:8080/projects/pdp-11/lsi-11.php LSI-11 Processors]

{{PDP-11}}

[[Category: PDP-11 Processors]]
[[Category: QBUS Processors]]