TSC2102 datasheet(18/54 Pages) TI

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TSC2102

SLAS379A− APRIL 2003 − REVISED JUNE 2004

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Table 1. Programmable PINTDAV Functionality

D15−D14

PINTDAV FUNCTION

Acts as PEN interrupt (active low) only. When PEN touch is detected, PINTDAV goes low.(1)

Acts as data available (active low) only. The PINTDAV goes low as soon as one set of ADC conversions are completed for data

of X,Y, XYZ, battery input, or auxiliary input selected by D13−D10 in REG00H/Page1. The resulting ADC output is stored in the

appropriate registers. The PINTDAV remains low and goes high only after this complete set of registers selected by D13−D10

REG00H/Page1 is read out.

Acts as both PEN interrupt and data available. When PEN touch is detected, PINTDAV goes low and remains low. The PINTDAV

goes high only after one set of A/D conversions is completed for data of X,Y, XYZ, battery input, or auxiliary input selected by

D13−D10 in REG00H/Page1.

(1) See the section Conversion Time Calculation for the TSC2102 in this data sheet for timing diagrams and conversion time calculations.

Pen-touch detect circuit is disabled during hardware power down.

Touch Screen Measurements

The touch screen ADC can be controlled by the host processor or can be self−controlled to offload processing from the

host processor. Bit D15 of REG00H/Page1 sets the control mode of the TSC2102 touch screen ADC; and bit D12 of

REG01H/Page 1 can be read to check the control mode status.

Conversion Controlled by TSC2102 Initiated at Touch Detect

In this mode, the TSC2102 detects when the touch panel is touched and causes the PINTDAV line to go low. At the same

time, the TSC2102 starts up its internal clock. Assuming the part was configured to convert XY coordinates, it then turns

on the Y drivers, and after a programmed panel voltage stabilization time, powers up the ADC and converts the Y

coordinate. If averaging is selected, several conversions may take place; when data averaging is complete, the Y

coordinate result is stored in the Y register.

If the screen is still touched at this time, the X drivers are enabled, and the process repeats, but measuring instead the X

coordinate, storing the result in the X register.

If only X and Y coordinates are to be measured, then the conversion process is complete. The time it takes to complete

this process depends upon the selected resolution, internal conversion clock rate, averaging selected, panel voltage

stabilization time, and precharge and sense times.

If the pressure of the touch is also to be measured, the process continues in the same way, measuring the Z1 and Z2 values,

and placing them in the Z1 and Z2 registers. As before, this process time depends upon the settings described above.

See the section Conversion Time Calculation for the TSC2102 in this data sheet for timing diagrams and conversion time

calculations.

Conversion Controlled by TSC2102 Initiated by the Host

In this mode, the TSC2102 detects when the touch panel is touched and causes the pen-interrupt signal line to go low. The

host recognizes the interrupt request, and then writes to the ADC control register (D13−D10 REG00H/Page1) to select one

of the touch screen scan functions. The host can either choose to initiate one of the scan functions, in which case the

TSC2102 controls the driver turnons, and wait times (e.g. upon receiving the interrupt the host can initiate the continuous

scan function X−Y−Z1−Z2 after which the TSC2102 controls the rest of conversion). The host can also choose to control

each aspect of conversion by controlling the driver turnons and start of conversions. For example, upon receiving the

interrupt request, the host turns on the X drivers. After waiting for the settling time, the host then addresses the TSC2102

again, this time requesting an X coordinate conversion, and so on.

The main difference between this mode and the previous mode is that the host, not the TSC2102, controls the touch screen

scan functions.

See the section Conversion Time Calculation for the TSC2102 in this data sheet for timing diagrams and conversion time

calculations.

TSC2102 Datasheet(PDF) 18 Page - Texas Instruments

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