Non-Processor Request and Grant - Revision history

Jnc: link some terms

2022-07-06T16:50:44Z

link some terms

Jnc: Add NPG, details of slot usage

2021-11-17T16:04:13Z

Add NPG, details of slot usage

Jnc: Jnc moved page Non-Processor Request to Non-Processor Request and Grant: Cover NPG too

2021-11-17T15:16:33Z

Jnc moved page Non-Processor Request to Non-Processor Request and Grant: Cover NPG too

Jnc: +cats

2018-12-19T23:36:29Z

+cats

Jnc: Proper cat

2018-10-20T01:38:33Z

Proper cat

Jnc: An OK start

2017-05-07T16:40:49Z

An OK start

New page

A '''Non-Processor Request''' is one of the two kinds of bus requests on the [[UNIBUS]]; it is used exclusively to gain control of the UNIBUS's data section so that the device may perform a [[DMA]] cycle.

The name comes from the fact that the device cannot request that the [[CPU]] perform any action (i.e. an [[interrupt]]) while the device has control of the bus.

A device gaining control of the UNIBUS via an NPR request ''may'' perform more than one [[master-slave cycle]] before relinquishing control of the bus, however.

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 A device gaining control of the bus via an NPR request ''may'' perform more than one [[master-slave cycle]] before relinquishing control of the bus, however.
-NPR is a normal 'wired-OR' broadcast bus line; NPG is a unidirectional [[bus grant line|grant line]]. In an [[Small Peripheral Controller|SPC]], etc [[backplane]] slot, there are a ''pair'' of pins for NPG: CA1 for 'NPG In', and CB1 for 'NPG Out'. In an empty slot, or a slot holding a non-DMA device, there must be either a [[jumper]] between those pins, or a [[G7273 grant continuity card]] installed, to carry the [[bus grant|grant]] across that slot.
+NPR is a normal [[wired-OR]] [[broadcast]] bus line; NPG is a unidirectional [[bus grant line|grant line]]. In an [[Small Peripheral Controller|SPC]], etc [[backplane]] slot, there are a ''pair'' of pins for NPG: CA1 for 'NPG In', and CB1 for 'NPG Out'. In an empty slot, or a slot holding a non-DMA device, there must be either a [[jumper]] between those pins, or a [[G7273 grant continuity card]] installed, to carry the [[bus grant|grant]] across that slot.
 The [[QBUS]] has a set of lines with identical functionality, [[DMA Request and Grant]].
 [[Category: UNIBUS]]

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-A '''Non-Processor Request''' is one of the two kinds of bus requests on the [[UNIBUS]] and [[QBUS]]; it is used exclusively to gain control of the UNIBUS's data section so that the device may perform a [[DMA]] cycle.
+The '''Non-Processor Request''' and '''Non-Processor Grant''' (usually given as their acronyms, '''NPR''' and '''NPG''') are the two [[conductor|lines]] on the [[UNIBUS]] used in one of the two kinds of [[bus grant|bus requests]] there; they are for a [[peripheral|device]] to gain control of the UNIBUS's data section so that it may perform a [[Direct Memory Access|DMA]] cycle.
-The name comes from the fact that the device cannot request that the [[CPU]] perform any action (i.e. an [[interrupt]]) while the device has control of the bus.
+The name comes from the fact that the device cannot request that the [[Central Processing Unit|CPU]] perform any action (i.e. an [[interrupt]]) while the device has control of the [[bus]].
-A device gaining control of the UNIBUS via an NPR request ''may'' perform more than one [[master-slave cycle]] before relinquishing control of the bus, however.
+A device gaining control of the bus via an NPR request ''may'' perform more than one [[master-slave cycle]] before relinquishing control of the bus, however.
-{{semi-stub}}
+NPR is a normal 'wired-OR' broadcast bus line; NPG is a unidirectional [[bus grant line|grant line]]. In an [[Small Peripheral Controller|SPC]], etc [[backplane]] slot, there are a ''pair'' of pins for NPG: CA1 for 'NPG In', and CB1 for 'NPG Out'. In an empty slot, or a slot holding a non-DMA device, there must be either a [[jumper]] between those pins, or a [[G7273 grant continuity card]] installed, to carry the [[bus grant|grant]] across that slot.
 [[Category: UNIBUS]]

@@ Line 1: / Line 1: @@
-A '''Non-Processor Request''' is one of the two kinds of bus requests on the [[UNIBUS]]; it is used exclusively to gain control of the UNIBUS's data section so that the device may perform a [[DMA]] cycle.
+A '''Non-Processor Request''' is one of the two kinds of bus requests on the [[UNIBUS]] and [[QBUS]]; it is used exclusively to gain control of the UNIBUS's data section so that the device may perform a [[DMA]] cycle.
 The name comes from the fact that the device cannot request that the [[CPU]] perform any action (i.e. an [[interrupt]]) while the device has control of the bus.
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 {{semi-stub}}

← Older revision		Revision as of 01:38, 20 October 2018
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	A device gaining control of the UNIBUS via an NPR request ''may'' perform more than one [[master-slave cycle]] before relinquishing control of the bus, however.		A device gaining control of the UNIBUS via an NPR request ''may'' perform more than one [[master-slave cycle]] before relinquishing control of the bus, however.

−	{{stub}}	+	{{semi-stub}}

← Older revision	Revision as of 15:16, 17 November 2021
(No difference)