Calibrating data transmission line spacing on a frame-scanning display device for optically transmitting data to a portable programmable device

In a computer system which uses selected data transmission raster lines of a frame-scanning display device for serial bit transmission to an external receiving device, wherein the data transmission raster lines are selected from a total number of available raster lines per display frame, a method of calibrating the spacing of the data transmission raster lines relative each other within the total number of available raster lines to establish a desired serial transmission bit rate, the method comprising the following steps:

• setting an internal timer of the computer system to generate timing signals at a predetermined frequency;
• counting the number of the timing signals which occur during a selected measurement period;
• counting the number of frame scans of the frame-scanning display device which occur during the selected measurement period;
• deriving a frame scan period of the frame-scanning display device based upon the predetermined frequency of the timing signals, the counted number of timing signals, and the counted number of frame scans;
• deriving a raster line period by dividing the derived frame scan period by the total number of available raster lines per display frame;
• and
• spacing the data transmission raster lines relative to each other within the total number of available raster lines in relationship to the raster line period, said spacing establishing the desired serial transmission rate to the external receiving device.

A computer system which uses selected data transmission raster lines of a frame-scanning display device for serial bit transmission to an external receiving device, the computer system comprising:

• a data processor;
• a frame-scanning display device having a total number of available raster lines per display frame;
• an internal timer which is set to generate timing signals at a predetermined frequency;
• the data processor being programmed to count the number of timing signals and the number of frame scans of the frame-scanning display device which occur during a selected measurement period;
• the data processor being further programmed to space the data transmission raster lines relative to each other within the total number of available raster lines as they appear on the frame-scanning display device based upon the predetermined frequency of the timing signals, the counted number of timing signals, and the counted number of frame scans, said spacing establishing a desired serial transmission bit rate to the external receiving device.

A computer system which uses selected data transmission raster lines of a frame-scanning display device for serial bit transmission to an external receiving device, the computer system comprising:

• a data processor;
• a frame-scanning display device having a total number of available raster lines per display frame;
• an internal timer which is set to generate timing signals at a predetermined frequency;
• the data processor being programmed to count the number of timing signals and the number of frame scans of the frame-scanning display device which occur during a selected measurement period;
• the data processor being further programmed to derive a frame scan period of the frame-scanning display device by dividing the counted number of timing signals by a product of the predetermined frequency of the timing signals and the counted number of frame scans;
• the data processor being further programmed to derive a raster line period by dividing the derived frame scan period by the total number of available raster lines per display frame;
• the data processor being further programmed to space the data transmission raster lines relative to each other within the total number of available raster lines as they appear on the frame-scanning display device in relationship to the derived frame scan period, said spacing establishing a desired serial transmission bit rate to the external receiving device.