Difference between revisions of "KW11-L Line Time Clock"

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[[Image:M787-KW11-L.jpg|300px|thumb|right|KW11-L card]]
 
[[Image:M787-KW11-L.jpg|300px|thumb|right|KW11-L card]]
  
The '''KW11-L Line Time Clock''' is a [[UNIBUS]] [[device]] option which provides clock [[interrupt]]s at a rate of 50 or 60 Hz, driven from the [[alternating current|AC]] power provided to the [[Central Processing Unit|CPU]]'s [[power supply]].
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The '''KW11-L Line Time Clock''' is a [[UNIBUS]] [[device]] option which provides [[clock]] [[interrupt]]s at a rate of 50 or 60 Hz, driven from the [[alternating current|AC]] power provided to the [[Central Processing Unit|CPU]]'s [[power supply]].
  
 
The programming interface is extremely simple; there is one [[register]], with two [[bit]]s; one to enable interrupts, and one which is set for every clock cycle (and causes an interrupt when that happens, if the other bit is set).
 
The programming interface is extremely simple; there is one [[register]], with two [[bit]]s; one to enable interrupts, and one which is set for every clock cycle (and causes an interrupt when that happens, if the other bit is set).
  
Physically, it is an [[DEC card form factor|extended-length]] single-height board, which plugs into a dedicated slot in the CPU's [[backplane]].
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Physically, the original KW11-L is an [[DEC card form factor|extended-length]] single-height board ('''M787'''), which plugs into a dedicated slot in the CPU's [[backplane]]. Only the [[PDP-11/20]], [[PDP-11/40]], [[PDP-11/45]] and [[PDP-11/70]] support the original card, although later [[PDP-11]]'s generally provided a program-compatible equivalent. E.g. on later UNIBUS machines (e.g. the [[PDP-11/04]] and [[PDP-11/34]]), the functionality was included in the [[DL11-W asynchronous serial line interface|DL11-W]].
 
 
Only the [[PDP-11/20]], [[PDP-11/40]], [[PDP-11/45]] and [[PDP-11/70]] support it. On later machines (e.g. the [[PDP-11/04]] and [[PDP-11/34]]), the functionality was included in the [[DL11-W asynchronous serial line interface|DL11-W]].
 
  
 
{{PDP-11}}
 
{{PDP-11}}
  
 
[[Category: UNIBUS Peripherals]]
 
[[Category: UNIBUS Peripherals]]

Latest revision as of 02:01, 14 January 2020

KW11-L card

The KW11-L Line Time Clock is a UNIBUS device option which provides clock interrupts at a rate of 50 or 60 Hz, driven from the AC power provided to the CPU's power supply.

The programming interface is extremely simple; there is one register, with two bits; one to enable interrupts, and one which is set for every clock cycle (and causes an interrupt when that happens, if the other bit is set).

Physically, the original KW11-L is an extended-length single-height board (M787), which plugs into a dedicated slot in the CPU's backplane. Only the PDP-11/20, PDP-11/40, PDP-11/45 and PDP-11/70 support the original card, although later PDP-11's generally provided a program-compatible equivalent. E.g. on later UNIBUS machines (e.g. the PDP-11/04 and PDP-11/34), the functionality was included in the DL11-W.