Difference between revisions of "QBUS"

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{| class="wikitable"
 
{| class="wikitable"
−
! Signal !! Pin
+
! Signal !! Pin !! Note !! Signal !! Pin !! Note
 
|-
 
|-
−
| BIRQ5 || AA1 (old BSpare1)
+
| BIRQ5 || AA1 || old BSpare1 || +5 || AA2
 
|-
 
|-
−
| BIRQ6 || AB1 (old BSpare2)
+
| BIRQ6 || AB1 || old BSpare2 || -12/-5 || AB2
 
|-
 
|-
−
| BDAL16 || AC1 (old BSpare3)
+
| BDAL16 || AC1 || old BSpare3 || Ground || AC2
 
|-
 
|-
−
| BDAL17 || AD1 (old BSpare4)
+
| BDAL17 || AD1 || old BSpare4 || +12 || AD2
 
|-
 
|-
−
| SSpare1 || AE1 (alt +5B)
+
| SSpare1 || AE1 || alt +5B || BDOUT || AE2
 
|-
 
|-
−
| SSpare2 || AF1 (alt SRUN/SMENBL on CF1)
+
| SSpare2 || AF1 || alt SRUN/SMENBL on CF1 || BRPLY || AF2
 
|-
 
|-
−
| SSpare3 || AH1 (alt SRUN on CH1)
+
| SSpare3 || AH1 || alt SRUN on CH1 || BDIN || AH2
 
|-
 
|-
−
| Ground || AJ1
+
| Ground || AJ1 || || BSYNC || AJ2
 
|-
 
|-
−
| MSpareA || AK1
+
| MSpareA || AK1 || || BWTBT || AK2
 
|-
 
|-
−
| MSpareB || AL1
+
| MSpareB || AL1 || || BIRQ4 || AL2 || was BIRQ
 
|-
 
|-
−
| Ground || AM1
+
| Ground || AM1 || || BIAKI || AM2
 
|-
 
|-
−
| BDMR || AN1
+
| BDMR || AN1 || || BIAKO || AN2
 
|-
 
|-
−
| BHALT || AP1
+
| BHALT || AP1 || || BBS7 || AP2
 
|-
 
|-
−
| BREF || AR1
+
| BREF || AR1 || || BDMGI || AR2
 
|-
 
|-
−
| +5B/+12B || AS1 (old PSpare3)
+
| +5B/+12B || AS1 || old PSpare3 || BDMGO || AS2
 
|-
 
|-
−
| Ground || AT1
+
| Ground || AT1 || || BINIT || AT2
 
|-
 
|-
−
| PSpare1 || AU1
+
| PSpare1 || AU1 || || BDAL00 || AU2
 
|-
 
|-
−
| +5B || AV1
+
| +5B || AV1 || || BDAL01 || AV2
 
|-
 
|-
 
|  
 
|  
 
|-
 
|-
−
| +5 || AA2
+
| BDCOK || BA1 || || +5 || BA2
 
|-
 
|-
−
| -12/-5 || AB2
+
| BPOK || BB1 || || -12/-5 || BB2
 
|-
 
|-
−
| Ground || AC2
+
| BDAL18 || BC1 || old SSpare4 || Ground || BC2
 
|-
 
|-
−
| +12 || AD2
+
| BDAL19 || BD1 || old SSpare5 || +12 || BD2
 
|-
 
|-
−
| BDOUT || AE2
+
| BDAL20 || BE1 || old SSpare6 || BDAL02 || BE2
 
|-
 
|-
−
| BRPLY || AF2
+
| BDAL21 || BF1 || old SSpare7 || BDAL03 || BF2
 
|-
 
|-
−
| BDIN || AH2
+
| SSpare8 || BH1 || || BDAL04 || BH2
 
|-
 
|-
−
| BSYNC || AJ2
+
| Ground || BJ1 || || BDAL05 || BJ2
 
|-
 
|-
−
| BWTBT || AK2
+
| MSpareB || BK1 || || BDAL06 || BK2
 
|-
 
|-
−
| BIRQ4 || AL2 (was BIRQ)
+
| MSpareB || BL1 || || BDAL07 || BL2
 
|-
 
|-
−
| BIAKI || AM2
+
| Ground || BM1 || || BDAL08 || BM2
 
|-
 
|-
−
| BIAKO || AN2
+
| BSACK || BN1 || || BDAL09 || BN2
 
|-
 
|-
−
| BBS7 || AP2
+
| BIRQ7 || BP1  || old PSpare6 || BDAL10 || BP2
 
|-
 
|-
−
| BDMGI || AR2
+
| BEVNT || BR1 || || BDAL11 || BR2
 
|-
 
|-
−
| BDMGO || AS2
+
| PSpare4/+12B || BS1 || || BDAL12 || BS2
 
|-
 
|-
−
| BINIT || AT2
+
| Ground || BT1 || || BDAL13 || BT2
 
|-
 
|-
−
| BDAL00 || AU2
+
| PSpare2 || BU1 || || BDAL14 || BU2
 
|-
 
|-
−
| BDAL01 || AV2
+
| +5 || BV1 || || BDAL15 || BV2
−
|-
+
|}
−
|
 
−
|-
 
−
|
 
−
|-
 
−
| BDCOK || BA1
 
−
|-
 
−
| BPOK || BB1
 
−
|-
 
−
| BDAL18 || BC1 (old SSpare4)
 
−
|-
 
−
| BDAL19 || BD1 (old SSpare5)
 
−
|-
 
−
| BDAL20 || BE1 (old SSpare6)
 
−
|-
 
−
| BDAL21 || BF1 (old SSpare7)
 
−
|-
 
−
| SSpare8 || BH1
 
−
|-
 
−
| Ground || BJ1
 
−
|-
 
−
| MSpareB || BK1
 
−
|-
 
−
| MSpareB || BL1
 
−
|-
 
−
| Ground || BM1
 
−
|-
 
−
| BSACK || BN1
 
−
|-
 
−
| BIRQ7 || BP1  (old PSpare6)
 
−
|-
 
−
| BEVNT || BR1
 
−
|-
 
−
| PSpare4/+12B || BS1
 
−
|-
 
−
| Ground || BT1
 
−
|-
 
−
| PSpare2 || BU1
 
−
|-
 
−
| +5 || BV1
 
−
|-
 
−
|  
 
−
|-
 
−
| +5 || BA2
 
−
|-
 
−
| -12/-5 || BB2
 
−
|-
 
−
| Ground || BC2
 
−
|-
 
−
| +12 || BD2
 
−
|-
 
−
| BDAL02 || BE2
 
−
|-
 
−
| BDAL03 || BF2
 
−
|-
 
−
| BDAL04 || BH2
 
−
|-
 
−
| BDAL05 || BJ2
 
−
|-
 
−
| BDAL06 || BK2
 
−
|-
 
−
| BDAL07 || BL2
 
−
|-
 
−
| BDAL08 || BM2
 
−
|-
 
−
| BDAL09 || BN2
 
−
|-
 
−
| BDAL10 || BP2
 
−
|-
 
−
| BDAL11 || BR2
 
−
|-
 
−
| BDAL12 || BS2
 
−
|-
 
−
| BDAL13 || BT2
 
−
|-
 
−
| BDAL14 || BU2
 
−
|-
 
−
| BDAL15 || BV2
 
  
 
==See also==
 
==See also==

Revision as of 17:11, 10 January 2016

The QBUS, previously known as the "LSI-11 bus", was intended as a cheaper alternative to the UNIBUS system by Digital Equipment Corporation.

It was widely used in PDP-11s and VAXen.

The bus had multiplexed address and data lines, and was available in 16-, 18-, and 22-address-bit configurations (data width remained 16 bits in all three versions).

Important note: The 16-bit and 18/22-bit backplanes are electrically incompatible and mixing the two may damage cards on the bus.

It is possible to upgrade 18-bit backplanes to 22-bit; see Upgrading QBUS backplanes.

Signalling

Like the UNIBUS, there are three basic kinds of cycles on the QBUS: data read/write cycles (in which a 'master' reads or writes data to/from a 'slave', which is usually, but not always, memory); DMA cycles (in which a device gains control of the bus so that it can do a read/write cycle); and interrupt cycles, in which a device causes the CPU to perform an interrupt.

All QBUS transactions are asynchronous, and use interlocked request/response signals for control and timing.

Pinout

QBUS pins are identified in the standard UNIBUS manner; there are two connectors, A and B; pins on the component side are 1, those on the solder side are 2. Pins are identified by the 'DEC alphabet', A-V, with G, I, O and Q dropped.

By signal

Signal Pin
Ground AJ1
Ground AM1
Ground AT1
Ground AC2
Ground BJ1
Ground BM1
Ground BT1
Ground BC2
+5 AA2
+5 BV1
+5 BA2
+5B AE1 *
+5B AS1 *
+5B AV1
+12 AD2
+12 BD2
+12B AS1 *
+12B BS1
-12 AB2
-12 BB2
BDAL00 AU2
BDAL01 AV2
BDAL02 BE2
BDAL03 BF2
BDAL04 BH2
BDAL05 BJ2
BDAL06 BK2
BDAL07 BL2
BDAL08 BM2
BDAL09 BN2
BDAL10 BP2
BDAL11 BR2
BDAL12 BS2
BDAL13 BT2
BDAL14 BU2
BDAL15 BV2
BDAL16 AC1
BDAL17 AD1
BDAL18 BC1
BDAL19 BD1
BDAL20 BE1
BDAL21 BF1
BBS7 AP2
BDIN AH2
BDOUT AE2
BREF AR1
BRPLY AF2
BSACK BN1
BSYNC AJ2
BWTBT AK2
BDCOK BA1
BEVNT BR1
BHALT AP1
BINIT AT2
BPOK BB1
BDMGI AR2
BDMGO AS2
BDMR AN1
BIAKI AM2
BIAKO AN2
BIRQ4 AL2
BIRQ5 AA1
BIRQ6 AB1
BIRQ7 BP1
SRUN AH1 *
ASpare2 BU1
MSpareA AK1
MSpareB AL1
MSpareB BK1
MSpareB BL1
PSpare1 AU1
PSpare2 BU1
PSpare4 BS1
SSpare1 AE1 *
SSpare2 AF1
SSpare3 AH1 *
SSpare8 BH1

Signals marked with a "*" show cases where two signals use the same pin (not at the same time, obviously).

By pin

Signal Pin Note Signal Pin Note
BIRQ5 AA1 old BSpare1 +5 AA2
BIRQ6 AB1 old BSpare2 -12/-5 AB2
BDAL16 AC1 old BSpare3 Ground AC2
BDAL17 AD1 old BSpare4 +12 AD2
SSpare1 AE1 alt +5B BDOUT AE2
SSpare2 AF1 alt SRUN/SMENBL on CF1 BRPLY AF2
SSpare3 AH1 alt SRUN on CH1 BDIN AH2
Ground AJ1 BSYNC AJ2
MSpareA AK1 BWTBT AK2
MSpareB AL1 BIRQ4 AL2 was BIRQ
Ground AM1 BIAKI AM2
BDMR AN1 BIAKO AN2
BHALT AP1 BBS7 AP2
BREF AR1 BDMGI AR2
+5B/+12B AS1 old PSpare3 BDMGO AS2
Ground AT1 BINIT AT2
PSpare1 AU1 BDAL00 AU2
+5B AV1 BDAL01 AV2
BDCOK BA1 +5 BA2
BPOK BB1 -12/-5 BB2
BDAL18 BC1 old SSpare4 Ground BC2
BDAL19 BD1 old SSpare5 +12 BD2
BDAL20 BE1 old SSpare6 BDAL02 BE2
BDAL21 BF1 old SSpare7 BDAL03 BF2
SSpare8 BH1 BDAL04 BH2
Ground BJ1 BDAL05 BJ2
MSpareB BK1 BDAL06 BK2
MSpareB BL1 BDAL07 BL2
Ground BM1 BDAL08 BM2
BSACK BN1 BDAL09 BN2
BIRQ7 BP1 old PSpare6 BDAL10 BP2
BEVNT BR1 BDAL11 BR2
PSpare4/+12B BS1 BDAL12 BS2
Ground BT1 BDAL13 BT2
PSpare2 BU1 BDAL14 BU2
+5 BV1 BDAL15 BV2

See also

Retrieved from "https://gunkies.org/w/index.php?title=QBUS&oldid=11391"