Claims
- 1. Calibration circuitry configured to calibrate a local raster of a local video subsystem to a remote raster of a remote video subsystem, the remote video subsystem for providing a sync signal to the local video subsystem, the local video subsystem including a local raster clock and a remote raster clock configured to generate a remote raster clock signal, the calibration circuitry comprising:
- processing logic configured to initialize the local raster clock with an initial clock count corresponding to a frequency of the local raster clock, the initialized local raster clock configured to be phase locked to the sync signal to thereby generate an estimate of the remote raster clock signal, wherein the estimated remote raster clock signal has an estimated remote raster clock frequency.
- 2. The calibration circuitry of claim 1, wherein the local raster clock is a phase locked loop.
- 3. In a computer system including a local video subsystem and a remote video subsystem, wherein the local video subsystem has a local raster and the remote video subsystem has a remote raster, the local raster has a local raster clock and the remote raster has a remote raster clock for generating a remote raster clock signal, the remote video subsystem for providing a sync signal to the local video subsystem, a method for calibrating the local raster to the remote raster, the method comprising the steps of:
- initializing the local raster clock with an initial clock count corresponding to a frequency of the local raster clock; and
- phase locking the local raster clock to the sync signal, so that the local raster clock generates an estimate of the remote raster clock signal, wherein the estimated remote raster clock signal has an estimated remote raster clock frequency.
- 4. The method of claim 3, wherein the local raster clock is a phase locked loop.
- 5. A computer system comprising:
- a display device;
- a bus;
- a processor coupled to the bus;
- a remote graphics subsystem coupled to the bus;
- a local video subsystem coupled to the bus, to the remote graphics subsystem and to the display device, said local video subsystem comprising logic to initialize a local raster clock of the local video subsystem with an initial clock count corresponding to a frequency of the local raster clock, the initialized local raster clock further configured to be phase locked to a sync signal provided by the remote graphics subsystem, said phase locked initialized local raster clock estimating a remote raster clock frequency of the remote graphics subsystem.
- 6. The computer system as set forth in claim 5, wherein the local raster clock comprises a phase locked loop.
- 7. The computer system as set forth in claim 5, wherein the initial count corresponds to an estimated number of total external clock pulses in a scan line.
Parent Case Info
This is a continuation of application application Ser. No. 08/367,957, filed Jan. 3, 1995 U.S. Pat. No. 5,668,594.
US Referenced Citations (8)
Continuations (1)
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Number |
Date |
Country |
Parent |
367957 |
Jan 1995 |
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