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]]. | + | The '''KW11-L Line Time Clock''' is a [[UNIBUS]] [[device]] option which provides a [[line time clock]], producing [[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, 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]]. | 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]]. | ||
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[[Category: UNIBUS Peripherals]] | [[Category: UNIBUS Peripherals]] | ||
Revision as of 03:20, 1 December 2021
The KW11-L Line Time Clock is a UNIBUS device option which provides a line time clock, producing 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.
