Difference between revisions of "KUV11 Writeable Control Store"
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It consists of a [[DEC card form factor|quad]] [[printed circuit board|card]] (M8018) which plugs into the [[QBUS]] [[backplane]] close to the [[Central Processing Unit|CPU]] card, and a [[flat cable]] which runs from the KUV11 to a free micro-[[Read-only memory|ROM]] [[chip socket]] on the CPU card, and gives the KUV11 access to the micro-instruction [[bus]]. | It consists of a [[DEC card form factor|quad]] [[printed circuit board|card]] (M8018) which plugs into the [[QBUS]] [[backplane]] close to the [[Central Processing Unit|CPU]] card, and a [[flat cable]] which runs from the KUV11 to a free micro-[[Read-only memory|ROM]] [[chip socket]] on the CPU card, and gives the KUV11 access to the micro-instruction [[bus]]. | ||
| − | The micro-store consists of 24 1Kx1 high-speed [[static RAM]] [[integrated circuit|chips]] | + | The micro-store consists of 24 1Kx1 high-speed [[static RAM]] [[integrated circuit|chips]]. The LSI-11 micro-[[word]] is 22 bits long; the extra two bits are fed to backplane pins (AE1 and AF1) to provide high-speed controls. A [[Dual Inline Package|DIP]] switch on the KUV11 controls where the micro-store appears in the micro-[[address space]]. |
The micro-words themseves are fed to the LSI-11 over the cable; the LSI-11 does not have the ability to write the micro-store contents over that cable, but has read-write access to it via the QBUS. That bus also provides access to a number of control [[register]]s on the KUV11. | The micro-words themseves are fed to the LSI-11 over the cable; the LSI-11 does not have the ability to write the micro-store contents over that cable, but has read-write access to it via the QBUS. That bus also provides access to a number of control [[register]]s on the KUV11. | ||
| − | The principle hardware debugging aid is the 'micro-[[address]] trace [[Random Access Memory|RAM]]', which is a 16-entry record of consecutive micro-addresses emitted as the micro-program runs, which can be frozen under program control, using one of the two extra bits in the micro-word. | + | The principle hardware debugging aid is the 'micro-[[address]] trace [[Random Access Memory|RAM]]', which is a 16-entry record of consecutive micro-addresses emitted as the micro-program runs, which can be frozen under program control, using one of the two extra bits in the extended micro-word. |
| − | == | + | ==External links== |
| − | * | + | * [http://www.bitsavers.org/pdf/dec/pdp11/1103/ PDP-11/03] - documentation at [[Bitsavers]] |
| + | ** [http://www.bitsavers.org/pdf/dec/pdp11/1103/EK-KUV11-TM_LSI11_WCS.pdf LSI-11 WCS user's guide] (EK-KUV11-TM-001) | ||
| + | ** [http://www.bitsavers.org/pdf/dec/pdp11/1103/LSI-11_User_Microcoding_Preliminary.pdf LSI-11 User Microcoding Preliminary] | ||
| + | ** [http://www.bitsavers.org/pdf/dec/pdp11/1103/M8018_LSI-11_WCS_Schematic.pdf Writeable Control Store Engineering Drawings] | ||
| + | * [http://www.vaxarchive.org/hardware/pdp11/wcsrc.tar WCS reference card] (images in TAR file) | ||
| − | + | [[Category: PDP-11 QBUS Processors]] | |
Latest revision as of 20:12, 2 July 2023
The KUV11 Writeable Control Store is an option for the LSI-11 which provides a user-programmable microcode memory extension, along with some hardware aids to debugging micro-programs. It allows additional, custom instructions to be added to the PDP-11 instruction set.
It consists of a quad card (M8018) which plugs into the QBUS backplane close to the CPU card, and a flat cable which runs from the KUV11 to a free micro-ROM chip socket on the CPU card, and gives the KUV11 access to the micro-instruction bus.
The micro-store consists of 24 1Kx1 high-speed static RAM chips. The LSI-11 micro-word is 22 bits long; the extra two bits are fed to backplane pins (AE1 and AF1) to provide high-speed controls. A DIP switch on the KUV11 controls where the micro-store appears in the micro-address space.
The micro-words themseves are fed to the LSI-11 over the cable; the LSI-11 does not have the ability to write the micro-store contents over that cable, but has read-write access to it via the QBUS. That bus also provides access to a number of control registers on the KUV11.
The principle hardware debugging aid is the 'micro-address trace RAM', which is a 16-entry record of consecutive micro-addresses emitted as the micro-program runs, which can be frozen under program control, using one of the two extra bits in the extended micro-word.
External links
- PDP-11/03 - documentation at Bitsavers
- WCS reference card (images in TAR file)
