Difference between revisions of "LSI-11"

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The '''LSI-11''' was DEC's first cost-reduced [[PDP-11]] processor, using the [[QBUS]]. Several different LSI-11 models exist, including the KDF11-F (quad form factor), and the KD11-HA (dual form factor), also called the '''LSI-11/2'''.
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[[Image:LSI-11.jpg|250px|thumb|right|M7264 KD11-F board (etch revision F), with KEV11-A]]
  
They were the first PDP-11 model to not have a front panel to control them; instead, as a cost-reduction measure, when the [[CPU]] is halted, specialized [[microcode]] used the main serial line as a operating console. The command set is named '''Octal Debugging Technique (ODT)'''; there are command to read and write memory, start the CPU, etc. The main serial interface is normally configured so that when the CPU is running, sending a [[asynchronous serial line|break]] on the console serial line halts the CPU.
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The '''LSI-11''' was DEC's first cost-reduced [[PDP-11]] [[Central Processing Unit|CPU]], introducing the [[QBUS]], and using the [[LSI-11 chip set]]. It was the first of the [[LSI-11 CPUs]]; it had the same QBUS limitations, and use of [[QBUS CPU ODT|ODT]] for control, as the others.
  
==Implementation==
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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.
  
All LSI-11 models use the same chip set internally, the Western Digital WD16/CP1600 (alternative designations). The chip set consists of a data path chip, a control chip, and two or three [[microcode]] [[Read-only memory|ROMs]] (each holding 512 words which are 22 bits wide).
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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). It also supported the optional [[KUV11 Writeable Control Store]].
  
The data path chip contains data paths, registers, and logic to perform [[micro-instruction]]s; it includes a register file, the [[ALU]], condition flags logic, and a data port which gives access to the QBUS' data/address line. The control chip contains micro-instruction sequencing, and control for the data port; it includes a 'programmable translation array', which decodes [[macro-instruction]]s to produce [[microcode]] addresses, the 'location counter' (micro-[[program counter]]), the 'return register' (microcode subroutine return), and interrupt logic.
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The [[integrated circuit|chip]] order (from the left, with the contact finger edge down, and the component side facing the viewer) is [[KEV11]], μROM 1, μROM 0, Control, Data Path.
  
The uROMs all have the same pinout, and are wired in parallel, so they can be placed in any of the three uROM positions. The first two uROMs contain the basic PDP-11 instruction set; the third uROM is optional, and a number of different choices are available. One is the [[KEV11-A]], for the EIS/[[FIS floating point|FIS]] instructions; the KEV11-B provides EIS without FIS.
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==Variant models==
  
The [[KEV11-C]] (see below for uROM information) provides a subset of the PDP-11 [[PDP-11 Commercial Instruction Set|CIS]], sometimes known as DIS ([[DIBOL]] instruction set). It also apparently includes the EIS (but not the FIS). DIS came as a standard in some commercial-oriented LSI-11 systems; the KD11-P and KD11-Q processors (M7264-BB and M7264-YB, respectively) are CPU models with the KEV11-C installed. The DIS cannot be used with the FIS, not only because of the limited number of uROM slots, but also because the DIS and basic instruction set together use the entire uROM address space.
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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.
  
==LSI-11==
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Others included various KEV11 chips pre-installed:
  
The LSI-11 is a quad board (M7264) with additional functionality on-board (making possible a single-board computer): the base KD11-F version includes 4KW of MOS RAM; the KD11-H version has the RAM deleted; the KD11-Q includes the KEV11-C.
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* the KD11-L is a KD11-F with a KEV11-A
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* the KD11-N is a KD11-H with a KEV11-A
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* the KD11-P is a KD11-F with a KEV11-C
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* the KD11-Q is a KD11-H with a KEV11-C
  
The 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.
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Some models include additional cards:
  
==LSI-11/2==
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* the KD11-J is a KD11-H sold with an [[MMV11-A QBUS core memory]] card
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* the KD11-R is a KD11-H sold with an [[MSV11-C QBUS MOS memory]] card
  
The LSI-11 is a dual board (M7270); it contains the processor, and nothing else.
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==See also==
  
'''''Note:''''' The image in the "Microcomputer Products Handbook" (pg. C-18) is erroneous; the order of the chips (from the handle end) is, in fact, KEV11, Control, uROM 1, uROM 0, Data Path (per the KD11-HA print set); the order given in the Handbook is that for the LSI-11 (no doubt an image was re-used without checking).
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* [[LSI-11/2]]
  
==Chip variants==
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==External links==
  
There are a number of variants of all the various uROM chips; it is not known if all variants are completely inter-operable (i.e. any revision of any chip can be replaced with any other, and have the machine still work), so combinations will be listed.
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* [http://web.frainresearch.org:8080/projects/pdp-11/lsi-11.php LSI-11 Processors]
 
 
Chip numbers of the form 23-xxxxx-rr, etc are DEC part numbers (where 'rr' seems to represent a revision number - 0, if not given); the corresponding Western Digital numbers are xxxxy, etc (where the 'x's are digits, and the 'y' a letter). The Data Path chip is a 1611H (various DEC part numbers), and the Control chip is a 2007C (ditto); the uROM chips are all 30xxy.
 
 
 
The following sets (Data, Control, uROMs) have been observed (the first three on dual cards):
 
 
 
* 1611H 21-11549-01, 2007C 23-002C4, 3010A 23-001B5, 3007D 23-002B5
 
* 1611H 21-16890, 2007C 23-002C4, 3010D 23-001B5, 3007D 23-007B5
 
* 1611H 21-16890, 2007C 23-003C4, 3010D 23-008B5, 3007D 23-007B5
 
* unknown, unknown, 3010D 23-001B5, 3007D 23-002B5
 
 
 
The 3010D contains uROM addresses 0x000-0x1ff, and the 3007D 23-002B5 contains 0x200-0x3ff.
 
 
 
For the KEV11-B, one version is known, the 23-090A5; it is suitable for the M7270 quad module etch revisions C and D.
 
 
 
The KEV11-C uses two uROMs, the 3025D 23-004B5 and 3026D (perhaps B?) 23-005B5. (There may also be a hybrid - i.e. single DIP carrier - version of the KEV11-C, but the part number is unknown.)
 
 
 
The version of the KEV11-C option with two uROMs obviously takes two uROM sockets; it is therefore used with a 40-pin hybrid (two chips on one carrier) which holds the two uROMs of the base instruction set. The hybrid is 23-001B6, 23-002B6, or 23-003B6 (for M7264 ECO 10, ECO 12, and ECO 16, respectively).
 
 
 
==Links==
 
 
 
* [https://github.com/brouhaha/cp16dis Microcode disassembler]
 
  
 
{{PDP-11}}
 
{{PDP-11}}
  
[[Category:QBUS processors]]
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[[Category: PDP-11 Processors]]
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[[Category: QBUS Processors]]

Revision as of 01:51, 5 March 2020

M7264 KD11-F board (etch revision F), with KEV11-A

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

The LSI-11 is a quad board (M7264) with additional functionality on-board. They were popular in OEM usage.

The usual CPU options were available for the LSI-11: the KEV11-A, for the EIS/FIS instructions; the KEV11-B provides EIS without FIS; the KEV11-C provides a subset of the PDP-11 CIS (it also apparently includes the EIS, but not the FIS). It also supported the optional KUV11 Writeable Control Store.

The chip order (from the left, with the contact finger edge down, and the component side facing the viewer) is KEV11, μROM 1, μROM 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 MOS 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:

See also

External links