FTG ISA Light Pen
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,	Pointing Devices

Overview

The FTG ISA Light Pen device driver provides support for an FTG Light Pen attached via an FTG PXL-395 internal interface adaptor.  

You can keep both the FTG light pen and a mouse or other pointing device active, allowing you to choose which pointing device is more useful for a given task.

Using the Light Pen over Black regions

The light pen positions the cursor by detecting light from the screen, which may be problematic when using the light pen over large black areas.  While this is not generally a problem with OPENSTEP for Mach's user interface, avoid setting the background to a very dark color.

Installing and Configuring an FTG Light Pen

First, install the PXL-395 adaptor as described in the FTG User Manual.  When setting the port address and interrupt jumpers on the PXL-395, make a note of the settings, because you will need this information when you use Configure.  NeXT recommends setting the Interrupt jumper to Auto.

Second, use Configure.app to configure the FTG ISA Light Pen device driver.  Specify a port address and interrupt number that match the jumper settings on the board.  If you jumpered "Auto", then you may select any available interrupt at this point.

After setting the port and interrupt numbers, save the configuration and quit Configure.  Restart the computer.  Log in as root and proceed to the Calibration process.

Calibrating the FTG Light Pen driver

You must calibrate the FTG ISA light pen driver the first time it is installed and any time a new display mode is selected.  Also, you can re-calibrate the light pen driver any time to improve cursor tracking.

Run Configure.app and select the FTG light pen driver.  If the light pen driver successfully registered at boot time, the Calibrate button will be enabled.  Click the Calibrate button and follow the instructions presented.  After calibrating, you should save the configuration.

Setting the Responsivity of the FTG Light Pen 

After completing calibration, you may wish to change the value of the Response field.  This controls the number of consecutive samples the driver averages to control the cursor location.  The higher the number, the slower and smoother the cursor motion.  The lower the number, the faster and more responsive the cursor is.  Larger numbers will help make the pen less jittery over large black regions.

After setting the Response control, save the configuration.

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See also

·	"Add a Device" in Configure's on-line help.

·	See NeXTAnswer 1824 for general information on installing and configuring device drivers.