Difference between revisions of "KTJ11-B UNIBUS adapter"

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[[Image:KTJ11-B.jpg|300px|thumb|right|KTJ11-B board]]
 
[[Image:KTJ11-B.jpg|300px|thumb|right|KTJ11-B board]]
  
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The '''KTJ11-B UNIBUS adaptor''' is used with the [[KDJ11-B CPU|KDJ11-B]] and [[KDJ11-E CPU|KDJ11-E]] [[QBUS]] [[Central Processing Unit|CPU]] cards to add [[UNIBUS]] capability to systems built around those CPU cards, the [[PDP-11/84]] and [[PDP-11/94]] systems respectively.
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The '''KTJ11-B UNIBUS adaptor''' is used with the [[KDJ11-B CPU|KDJ11-B]] and [[KDJ11-E CPU|KDJ11-E]] [[QBUS]] [[Central Processing Unit|CPU]] cards in the special [[KDJ11 PMI/UNIBUS backplane]] to add [[UNIBUS]] capability to systems built around those cards; the [[PDP-11/84]] and [[PDP-11/94]] systems respectively. It converts the native [[Private Memory Interconnect]] (PMI) [[bus]] supported by these CPUs to the [[Digital Equipment Corporation|DEC]]-standard UNIBUS.
  
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It is a [[DEC card form factor|hex-height]] board ('''M8191'''), and can only plug into a special [[backplane]], unique to those systems, which is wired to support it.  
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It is a [[DEC card form factor|hex-height]] board ('''M8191'''), and can only plug into the special [[backplane]], unique to those systems, which is wired to support it.  
  
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==Backplane details==
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==Technical details==
  
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The custom 12+1 slot backplane used by the KTJ11-B was half QBUS, and half UNIBUS (the 13th 'slot' is not a full slot, it only has a [[DEC edge connector contact identification|connector]] for one set of fingers). It has [[Private Memory Interconnect]] (PMI) bus slots at the top (for the CPU and [[main memory]] cards), a special slot in the middle for the KTJ11-B, and then UNIBUS slots.
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The KTJ11-B contains a [cache]], to increase the efficiency of [[Direct Memory Access|DMA]] transfers on the UNIBUS; generally, two DMA red cycles on the UNIBUS result in a single PMI bus read operation. The cache contains 32 [[word]]-width entries, arranged into 4 independent 8-word sets; the KTJ11-B can thus handle 4 simultaneous DMA operations on the UNIBUS efficiently.
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In detail, the backplane contains (in order) four [[DEC card form factor|quad-height]] slots, the first of which is the custom partial slot, and the others are PMI (technically [[QBUS#Variable address size|Q22]]/[[CD interconnect|CD]], although slightly modified from the normal form of that in this backplane, see below); they are used for (in order, from the front of the machine):
 
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* the Machine Debug Monitor board (M7677); this slot is not numbered
 
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* the CPU board; this is slot 1
 
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* main memory board
 
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* optional second main memory board
 
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and nine hex-height slots, used for:
 
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* KTJ11-B UNIBUS adapter, in slot 4
 
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* four [[Small Peripheral Controller|SPC]] UNIBUS slots
 
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* three [[Modified UNIBUS Device|MUD]] UNIBUS slots
 
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* UNIBUS 'out' and quad SPC slot, in slot 12
 
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Note that the PMI slots do not have the [[Private Memory Interconnect#CD interconnect details|bottom-up]] ordering of PMI-capable slots in a Q22/CD backplane, but are wired as a true bus, allowing the 'CPU, memory, memory' insertion ordering seen here.
 
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Note also that in the normal configuration (see below for details), the QBUS [[bus grant line]]s are not routed through the memory slots, so if one of these slot is unused, there is no need for a [[M9047 grant continuity card]] in that slot.
 
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As a further feature, on most UNIBUS backplanes, the 'NPG' ([[Direct Memory Access|DMA]] grant line) signal is carried across unused slots by wire jumpers on [[wire-wrap]] pins on the back side of the backplane; on the -11/84 backplane, they are brought out to a [[Dual Inline Package|DIP]] switch on the MDM module, for easier configuration changes.
 
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Any UNIBUS slot which does not have a device installed in it, must have a [[bus grant|grant]] continuity card such as a [[G7273 grant continuity card|G7273]] placed in it.
 
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===Backplane layout===
 
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Board locations are:
 
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<!-- (as seen from the board insertion side of the backplane, not the wire-wrap pin side, as is common in [[Digital Equipment Corporation|DEC]] documentation) -->
 
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{| class="wikitable"
 
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! !! colspan="6" | Connector
 
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|-
 
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! Slot !! A !! B !! C !! D !! E !! F
 
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|-
 
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| 0 || colspan="4" style="text-align:center;" | M7677 MDM
 
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|-
 
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| 1 || colspan="4" style="text-align:center;" | M8190 or M8981 CPU
 
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|-
 
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| 2 || colspan="4" style="text-align:center;" | PMI memory
 
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|-
 
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| 3 || colspan="4" style="text-align:center;" | PMI memory
 
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|-
 
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| 4 || colspan="6" style="text-align:center;" | M8191 UBA
 
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|-
 
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| 5 || colspan="6" style="text-align:center;" | SPC device
 
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|-
 
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| 6 || colspan="6" style="text-align:center;" | SPC device
 
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|-
 
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| 7 || colspan="6" style="text-align:center;" | SPC device
 
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|-
 
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| 8 || colspan="6" style="text-align:center;" | SPC device
 
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|-
 
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| 9 || colspan="6" style="text-align:center;" | MUD device
 
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|-
 
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| 10 || colspan="6" style="text-align:center;" | MUD device
 
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|-
 
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| 11 || colspan="6" style="text-align:center;" | MUD device
 
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|-
 
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| 12 || colspan="2" style="text-align:center;" | UNIBUS Out || colspan="4" style="text-align:center;" | SPC
 
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|}
 
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''Note:'' In an -11/94, there will usually be no PMI memory, but there will be an M9714 Alternate Power Source cards in connectors A-B of slot 2.
 
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===QBUS slots===
 
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The two main memory slots can in fact be configured as regular Q22/CD QBUS slots, by removing two jumpers. EK-PDP84-TM-PR4 (PDP-11/84 Technical Manual) says (in section 2.1.14, "Backplane (H9277-A)", pg. 2-6):
 
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: ''Bus signals BDMGI (pin AR2) and BIAKI (pin AM2) for slots 2 & 3 are jumpered on the front of the backplane.''
 
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There are indeed two jumpers, W1 and W2 (in the upper right-hand corner, when facing the backplane from the board insertion side); the traces connected to them are on the surface, so it is possible to see where they go: one end runs to a trace connected from slot 1 to slot 2, and the other to a trace connected from slot 3 to slot 4; those connect to AM2 (BIAKI) and AN2 (BIAKO), and AR2 (BDMGI) and AS2 (BDMGO).
 
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Thus, when the jumpers are in, the CPU's BIAKO/BDMGO pins are connected directly to the UNIBUS adapter's BIAKI/BDMGI pins; when they are out, those signals are routed through the two 'memory' slots, in the normal QBUS manner.
 
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It therefore seems those two slots ''might'' be able to function as real QBUS slots. However, it is not clear that the CPU will 'do the right thing'; the UNIBUS adapter puts out a signal to let the CPU know that it is there, and the CPU may then expect to see only PMI-type DMA and [[interrupt]] cycles on the bus.
 
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The DMA cycle ''might'' work, it all depends on what happens at step 8 (EK-KDJ1B-UG-001, pp. 7-6 to 7-9) when, instead of PBSY being asserted, BSYNC is asserted. The PMI ''memory'' will be fine (since in an -11/83, this kind of thing is expected)... but the ''CPU'', who knows. (The CPU would do the right thing in an -11/83, but the same board might not do the right thing here, since it 'knows' there is a UNIBUS adapter present.)
 
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Interrupt cycles are more problematic; the assertion of the interrupt level on the BDAL lines (step 1a) will probably pass, but step 6 (assertion of BSACK) may be an issue, since the device will want to assert BRPLY instead (BSACK is not used in a QBUS interrupt), and the CPU may not do the right thing.
 
  
 
==External links==
 
==External links==
  
 
* [http://www.bitsavers.org/pdf/dec/pdp11/1184/EK-1184E-TM-001_Dec87.pdf PDP-11/84 System Technical and Reference Manual] (EK-1184E-TM-001) - the KTJ11-B is covered on pp. 68-85 of the PDF
 
* [http://www.bitsavers.org/pdf/dec/pdp11/1184/EK-1184E-TM-001_Dec87.pdf PDP-11/84 System Technical and Reference Manual] (EK-1184E-TM-001) - the KTJ11-B is covered on pp. 68-85 of the PDF
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* [http://www.bitsavers.org/pdf/dec/pdp11/handbooks/PDP-11_Systems_Handbook_1987.pdf PDP-11 Systems Handbook] (EB 29317 41) - the KTJ11-B is covered on pp. 143-147 of the PDF
 
* [http://www.bitsavers.org/pdf/dec/pdp11/1184/MP-02015-01_11-84_Maintenance_Print_Set_198412.pdf 11/84 Field Maintenance Print Set (MP-02015-001)] - Contains KTJ11-B Field Maintenance Print Set (MP-02010-01) on pp. 127-156
 
* [http://www.bitsavers.org/pdf/dec/pdp11/1184/MP-02015-01_11-84_Maintenance_Print_Set_198412.pdf 11/84 Field Maintenance Print Set (MP-02015-001)] - Contains KTJ11-B Field Maintenance Print Set (MP-02010-01) on pp. 127-156
  
 
[[Category: PDP-11 UNIBUS Processors]]
 
[[Category: PDP-11 UNIBUS Processors]]
 
[[Category: UNIBUS]]
 
[[Category: UNIBUS]]
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[[Category: Private Memory Interconnect]]

Latest revision as of 01:07, 8 October 2024

KTJ11-B board

The KTJ11-B UNIBUS adaptor is used with the KDJ11-B and KDJ11-E QBUS CPU cards in the special KDJ11 PMI/UNIBUS backplane to add UNIBUS capability to systems built around those cards; the PDP-11/84 and PDP-11/94 systems respectively. It converts the native Private Memory Interconnect (PMI) bus supported by these CPUs to the DEC-standard UNIBUS.

It is a hex-height board (M8191), and can only plug into the special backplane, unique to those systems, which is wired to support it.

Technical details

The KTJ11-B contains a [cache]], to increase the efficiency of DMA transfers on the UNIBUS; generally, two DMA red cycles on the UNIBUS result in a single PMI bus read operation. The cache contains 32 word-width entries, arranged into 4 independent 8-word sets; the KTJ11-B can thus handle 4 simultaneous DMA operations on the UNIBUS efficiently.

External links

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