Difference between revisions of "Extended UNIBUS"

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The '''Extended UNIBUS''' or '''EUB''' was [[DEC]]'s name for both an upgrade to their standard [[UNIBUS]] [[PDP-11]] bus, to add additional address lines, in order to support larger memories; and also for the slots in a [[backplane]] which instantiated the bus. The slots were [[DEC card form factor|hex]] slot, and could hold only special EUB memory cards, the only EUB cards ever produced.
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The '''Extended UNIBUS''' or '''EUB''' was [[DEC]]'s name for both an upgrade to their standard [[UNIBUS]] [[PDP-11]] bus, to add additional address lines, in order to support larger memories; and also for the slots in a [[backplane]] which instantiated the bus. The added address lines are A18-A21.
  
The only machines to support the EUB were the [[PDP-11/44]] and [[PDP-11/24]], which had a limited number of EUB slots in their main backplanes (the ones which held their CPUs). In the -11/24, at least, the EUB slots can also support a normal [[Small Peripheral Controller|SPC]] device, in the [[DEC card form factor#Edge connector contact identification|C-F connectors]] usually used for SPC devices in hex slots.
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The slots were [[DEC card form factor|hex]] slot, and could hold only special EUB memory cards, the only EUB cards ever produced. The only machines to support the EUB were the [[PDP-11/44]] and [[PDP-11/24]], which had a limited number of EUB slots in their main backplanes (the ones which held their CPUs).
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In the -11/24, at least, the EUB slots can also support a normal [[Small Peripheral Controller|SPC]] device, in the [[DEC card form factor#Edge connector contact identification|C-F connectors]] usually used for SPC devices in hex slots.
  
 
EUB slots differed from the older [[Modified UNIBUS Device|MUD]] slots in that they re-purposed some of the pins in the A/B rows to carry EUB signals (A18-A21, principally), thus making it not pin-compatible with the usual dual UNIBUS slot).
 
EUB slots differed from the older [[Modified UNIBUS Device|MUD]] slots in that they re-purposed some of the pins in the A/B rows to carry EUB signals (A18-A21, principally), thus making it not pin-compatible with the usual dual UNIBUS slot).
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==EUB memory boards==
  
 
The only EUB-capable memories which DEC produced were the [[MS11-L]], [[MS11-M]], and [[MS11-P]]. The first two were jumperable for use on either the UNIBUS or EUB, although the second used the unusual power voltage of +12V, which most backplanes did not supply.
 
The only EUB-capable memories which DEC produced were the [[MS11-L]], [[MS11-M]], and [[MS11-P]]. The first two were jumperable for use on either the UNIBUS or EUB, although the second used the unusual power voltage of +12V, which most backplanes did not supply.
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Other manufacturers also produced EUB memories.
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 +
==Pinout==
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The pins which changed from MUD to EUB are:
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* AB1 - Reserved
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* AB2 - Boot Enable
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* AN1 - A21
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* AP1 - A20
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* AP2 - Reserved
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* AR1 - +15V/12V Battery
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* AR2 - Reserved
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* AS1 - +15V/12V Battery
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* AS2 - Reserved
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* AU1 - Reserved
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* AU2 - Reserved
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* AV1 - Reserved
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* AV2 - Reserved
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* BA1 - Reserved
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* BB1 - +5V Battery
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* BB2 - Reserved
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* BD1 - +5V Battery
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* BE1 - A19
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* BE2 - A18
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* BV2 - Reserved
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 +
{{PDP-11}}

Revision as of 14:18, 22 July 2016

The Extended UNIBUS or EUB was DEC's name for both an upgrade to their standard UNIBUS PDP-11 bus, to add additional address lines, in order to support larger memories; and also for the slots in a backplane which instantiated the bus. The added address lines are A18-A21.

The slots were hex slot, and could hold only special EUB memory cards, the only EUB cards ever produced. The only machines to support the EUB were the PDP-11/44 and PDP-11/24, which had a limited number of EUB slots in their main backplanes (the ones which held their CPUs).

In the -11/24, at least, the EUB slots can also support a normal SPC device, in the C-F connectors usually used for SPC devices in hex slots.

EUB slots differed from the older MUD slots in that they re-purposed some of the pins in the A/B rows to carry EUB signals (A18-A21, principally), thus making it not pin-compatible with the usual dual UNIBUS slot).

EUB memory boards

The only EUB-capable memories which DEC produced were the MS11-L, MS11-M, and MS11-P. The first two were jumperable for use on either the UNIBUS or EUB, although the second used the unusual power voltage of +12V, which most backplanes did not supply.

Other manufacturers also produced EUB memories.

Pinout

The pins which changed from MUD to EUB are:

  • AB1 - Reserved
  • AB2 - Boot Enable
  • AN1 - A21
  • AP1 - A20
  • AP2 - Reserved
  • AR1 - +15V/12V Battery
  • AR2 - Reserved
  • AS1 - +15V/12V Battery
  • AS2 - Reserved
  • AU1 - Reserved
  • AU2 - Reserved
  • AV1 - Reserved
  • AV2 - Reserved
  • BA1 - Reserved
  • BB1 - +5V Battery
  • BB2 - Reserved
  • BD1 - +5V Battery
  • BE1 - A19
  • BE2 - A18
  • BV2 - Reserved