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Clock Timer

IP.com Disclosure Number: IPCOM000035647D
Original Publication Date: 1989-Jul-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 2 page(s) / 14K

Publishing Venue

IBM

Related People

O'Toole, JF: AUTHOR [+2]

Abstract

A clock timer card contains a clock and control logic. The card can be addressed by the various processors in the terminal. The processors can perform the following operations: 1. Send a control word to the special card; 2. Read the control word from the card; 3. Set the frequency of the clock on the card; and 4. Read out the contents of the clock.

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Clock Timer

A clock timer card contains a clock and control logic. The card can be addressed by the various processors in the terminal. The processors can perform the following operations: 1. Send a control word to the special card; 2. Read the control word from the card; 3. Set the frequency of the clock on the card; and 4. Read out the contents of the clock.

The card and microcode were developed to measure the time for display program orders and various hardware functions. Previous method required the attachment of probes to a measurement tool. This method allows one to measure terminals without attaching probes.

Performance is a critical factor in the operation of Graphics Programs. One can see directly on the display the effects caused by buffer programs which take a long time to run. It is time consuming, however, to establish the amount of time spent by each of the many components in a buffer program. Clock Timer Function

The timer card contains a counter and the required logic to control its stepping and read out. The logic will also allow the clock to be set to one of several frequencies. A predefined address on the system bus will be used to retrieve the current clock value.

The counter runs in one of two modes; the user selects the desired mode by bits in the control word.

Interval - In this mode, the clock is reset each time it is read out.

Continuous - In this mode, the clock will not be reset on read out. Control Word

The control word specifies the frequency at which the clock is to run. Selected bits in the control word specify the mode of operation, and will also control resetting of the clock. When the control word is written to the clock card, it is latched in a register.

The data in the control word register may be retrieved to determine the current clock setting and mode. Four bits are reserved in the control word for user information. These bits can be used when it is possible that there might be more than one user of the clock. Prior to changing the control word, a user would read it out. An "in use" bit can be assigned so that a subsequent user would not change the mode or frequency until the first test was complete. 11 1111 0123 4567 8901 2345 smrx uuuu ffff ffff Bit(s) Function 0 s = 0, Set clock frequency (using bits 8-15) s = 1, Inhibit changing the clock frequency 1 m = 0, Mode = Interval (Clock will be reset on read out) m = 1, Mode = Continuous 2 r = 0, Inhibit clock reset. (When s = 0, then thi...