Difference between revisions of "KD11-K CPU"

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(External links: +FMPS, manuals - also backplane layout)
(External links: Narrow down category.)
 
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The '''KD11-K''' was the [[Central Processing Unit|CPU]] of the [[PDP-11/60]]. It provided the [[PDP-11 Memory Management|subset PDP-11 memory management]], and used the [[UNIBUS]] for its [[main memory]] access (although a built-in [[cache]] was standard).
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The '''KD11-K''' was the [[Central Processing Unit|CPU]] of the [[PDP-11/60]]. It provided the [[PDP-11 Memory Management|subset PDP-11 memory management]], and used a [[UNIBUS]] for its [[main memory]] access (although a built-in [[cache]] was standard).
  
 
It provided the full [[FP11 floating point]] using [[microcode]]; as an option, the [[FP11-E Floating Point Processor]], a 4 hex board [[co-processor]] which provided a high-performance implementation, was also available. Also available were either a User Control Store (1KW of read-write microcode), an Extended Control Store ([[ROM]] microcode), or a Diagnostic Control Store.
 
It provided the full [[FP11 floating point]] using [[microcode]]; as an option, the [[FP11-E Floating Point Processor]], a 4 hex board [[co-processor]] which provided a high-performance implementation, was also available. Also available were either a User Control Store (1KW of read-write microcode), an Extended Control Store ([[ROM]] microcode), or a Diagnostic Control Store.
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 +
One unusual aspect was that the CPU's [[backplane]] had a separate UNIBUS connectors for [[input/output|I/O]] activity, and for memory access. The FMPS indicates (pg. 4) that devices that do [[interrupt]]s and [[Direct Memory Access|DMA]] must be connected to the I/O UNIBUS, and not to the memory UNIBUS; but it also indicates (pg. 3) that there is only a single UNIBUS. (Perhaps all the [[bus grant line]]s from the bus arbitration circuitry in the CPU are only connected to the I/O connector?)
  
 
==Microcode==
 
==Microcode==
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==Implementation==
 
==Implementation==
  
It consisted of a custom 14-slot [[backplane]], and 6 [[DEC card form factor|hex]] [[printed circuit board|boards]]:
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It consisted of a custom 14-slot backplane (([[DEC part number]] 70-12953), and 6 [[DEC card form factor|hex]] [[printed circuit board|boards]]:
  
 
* uWord (M7872)
 
* uWord (M7872)
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! Slot !! A !! B !! C !! D !! E !! F
 
! Slot !! A !! B !! C !! D !! E !! F
 
|-
 
|-
| 1 || colspan="6" style="text-align:center;" | WCS/ECS/DCS (optional)
+
| 1 || colspan="6" style="text-align:center;" | WCS or ECS or DCS (optional)
 
|-
 
|-
 
| 2 || colspan="6" style="text-align:center;" | uWord (M7872)
 
| 2 || colspan="6" style="text-align:center;" | uWord (M7872)
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| 12 || colspan="2" style="text-align:center;" | Unused || colspan="4" style="text-align:center;" | SPC
 
| 12 || colspan="2" style="text-align:center;" | Unused || colspan="4" style="text-align:center;" | SPC
 
|-
 
|-
| 13 || colspan="2" style="text-align:center;" | Bootstrap || colspan="4" style="text-align:center;" | SPC
+
| 13 || colspan="2" style="text-align:center;" | Memory UNIBUS/Bootstrap || colspan="4" style="text-align:center;" | SPC
 
|-
 
|-
| 14 || colspan="2" style="text-align:center;" | UNIBUS Out || colspan="4" style="text-align:center;" | SPC  
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| 14 || colspan="2" style="text-align:center;" | I/O UNIBUS/Terminator || colspan="4" style="text-align:center;" | SPC  
 
|}
 
|}
  
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** [http://www.bitsavers.org/pdf/dec/pdp11/1160/MP00500_1160WCS_Nov77.pdf KU116-AA Field Maintenance Print Set] (MP00500)
 
** [http://www.bitsavers.org/pdf/dec/pdp11/1160/MP00500_1160WCS_Nov77.pdf KU116-AA Field Maintenance Print Set] (MP00500)
  
[[Category: PDP-11 Processors]]
+
[[Category: PDP-11 UNIBUS Processors]]
[[Category: UNIBUS Processors]]
 

Latest revision as of 12:34, 11 October 2022

The KD11-K was the CPU of the PDP-11/60. It provided the subset PDP-11 memory management, and used a UNIBUS for its main memory access (although a built-in cache was standard).

It provided the full FP11 floating point using microcode; as an option, the FP11-E Floating Point Processor, a 4 hex board co-processor which provided a high-performance implementation, was also available. Also available were either a User Control Store (1KW of read-write microcode), an Extended Control Store (ROM microcode), or a Diagnostic Control Store.

One unusual aspect was that the CPU's backplane had a separate UNIBUS connectors for I/O activity, and for memory access. The FMPS indicates (pg. 4) that devices that do interrupts and DMA must be connected to the I/O UNIBUS, and not to the memory UNIBUS; but it also indicates (pg. 3) that there is only a single UNIBUS. (Perhaps all the bus grant lines from the bus arbitration circuitry in the CPU are only connected to the I/O connector?)

Microcode

It was a microcoded CPU, using 48-bit wide micro-words; the address space of the micro-engine was 212 words, divided into 8 blocks. The allocation of the blocks was:

  1. Base instructions
  1. Console and Error log
  2. EIS, Initialization
  3. Floating point
  4. Floating point
  5. ECS
  6. ECS/UCS
  7. ECS/UCS

Implementation

It consisted of a custom 14-slot backplane ((DEC part number 70-12953), and 6 hex boards:

  • uWord (M7872)
  • Decode (M7873)
  • Data Path (M7874)
  • KT/Cache (M7875)
  • Timing (M7876)
  • Status (M7827)

for the basic CPU. They were held in slots 2-7 of the backplane:

Connector
Slot A B C D E F
1 WCS or ECS or DCS (optional)
2 uWord (M7872)
3 Decode (M7873)
4 Data Path (M7874)
5 KT/Cache (M7875)
6 Timing (M7876)
7 Status (M7827)
8 Floating Point Next Micro-Address (M7878)
9 Floating Point Exponent (M7879)
10 Multiplying Network (M7880)
11 Floating Point ALU (M7881)
12 Unused SPC
13 Memory UNIBUS/Bootstrap SPC
14 I/O UNIBUS/Terminator SPC

The optional FPP used slots 8-11 of the backplane; a single slot, slot 1, held the microcode option. The remaining slots in the backplane, 12-14, were SPC slots.

External links