LM8500-REF-01 National Semiconductor, LM8500-REF-01 Datasheet - Page 16

• Manufacturer Part Number: LM8500-REF-01
• Description: BOARD EVALUATION LM8500
• Manufacturer: National Semiconductor

Specifications of LM8500-REF-01

• Main Purpose: Interface, Touch Screen Controller
• Utilized Ic / Part: LM8500
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• Secondary Attributes: -
• Embedded: -
• Primary Attributes: -

The Diagnostics program
To access the Diagnostics program to change various setting on the touch screen controller, click
on Start|Programs|UPDD|Diagnostics
Comms Mode – The default setting is stream mode. In this mode, the driver will interpret all
touches on the touch panel. The other modes are touchdown and liftoff. In the touchdown
mode, the driver will only receive data from the TSC when a touchdown is detected on the panel.
In the liftoff mode, the driver will only receive data from the TSC when a liftoff is detected on
the panel. It is necessary to first select the desired communication mode then press the Comms
Mode button for the changes to be sent to the device.
Samples per Coordinate – The default setting is 8 samples per coordinate. The other available
settings are 1, 2, 4, 16, and 32 samples per coordinate. Keep in mind that higher settings might
cause the mouse pointer to trail the actual position of the touch. It is necessary to first select the
desired number of samples then press the Samples button for the changes to be sent to the device
Focus Value – The default setting is 4. For more information on what the Focus Value does,
please refer to the datasheet.
Max Delta – The default setting is 8. For more information on what the Max Delta does, please
refer to the datasheet.
Min Pressure – The default setting is 40. The Min Pressure is used by the device to determine
how hard a touch must be on the detected on the panel to be considered a valid touch. Please
note, too high of a Min Pressure value might cause touches on the corner of the touch panel to
be not considered valid by the device.
Pressure – When enabled, the TSC will send the pressure measurement in addition to the X-Y
coordinates. With the pressure measurement enabled, more data bytes are sent from the TSC to
the driver; thus the coordinate pairs per second (CPPS) will be lower.
Power Down – The self-power down mode is enabled by default. The option is used to conserve
power. If disabled, the TSC will always be on and will consume more power.
Diagnostics Tab – This allows the
changing of the various options on
the LM8300/8500