Difference between revisions of "Small Peripheral Controller"
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'''Small Peripheral Controller''' was [[DEC]]'s name for an I/O board slot in the [[backplane]]s of [[UNIBUS]] [[PDP-11]]s. It was a [[DEC card form factor|quad]] slot, and could hold any kind of device. | '''Small Peripheral Controller''' was [[DEC]]'s name for an I/O board slot in the [[backplane]]s of [[UNIBUS]] [[PDP-11]]s. It was a [[DEC card form factor|quad]] slot, and could hold any kind of device. | ||
| − | SPC slots were wired to bring all 4 UNIBUS grant lines through the device; the board | + | SPC slots were wired to bring all 4 UNIBUS grant lines through the device; the board generally had a header which routed the grant (and matching request) line for the desired priority level to the on-board interrupt circuity, and passed the other grant lines through. The DMA (NPG) grant line generally had a jumper on the backplane, which had to be removed if a DMA device was plugged into the slot. Un-occupied slots needed to have a grant continuity card installed. |
Revision as of 15:22, 25 March 2016
Small Peripheral Controller was DEC's name for an I/O board slot in the backplanes of UNIBUS PDP-11s. It was a quad slot, and could hold any kind of device.
SPC slots were wired to bring all 4 UNIBUS grant lines through the device; the board generally had a header which routed the grant (and matching request) line for the desired priority level to the on-board interrupt circuity, and passed the other grant lines through. The DMA (NPG) grant line generally had a jumper on the backplane, which had to be removed if a DMA device was plugged into the slot. Un-occupied slots needed to have a grant continuity card installed.
