Difference between revisions of "KD11-K CPU"
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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 '''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. | ||
| + | |||
| + | 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 [[interupt]]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 [[ | + | 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 | + | | 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) | ||
Revision as of 23:51, 11 January 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 interupts 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:
- Base instructions
- Console and Error log
- EIS, Initialization
- Floating point
- Floating point
- ECS
- ECS/UCS
- 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 | Bootstrap | SPC | ||||
| 14 | UNIBUS Out | 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
- PDP-11/60 - BitSavers
