DS41393A-Page 12

© 2009 Microchip Technology, Inc.

7.12 Configuration Registers

The Configuration Registers allow application specific customization of the controller. The default values have

been optimized for most applications and are automatically used, unless you choose to change them.

Unique sensors and/or product applications may benefit from adjustment of configuration registers.

The factory default settings for the Configuration registers can be recovered by writing a value of 0xFF to address

0x00 of the EEPROM, then cycling power.

Register Name

Address

Offset

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Default

Value

TouchThreshold

0x02

Value of: 0-255

0xC5

SensitivityFilter

0x03

Value of: 0-255

0x04

SamplingFast

0x04

Value of: 1, 2, 4, 8, 16, 32, 64, 128

0x04

SamplingSlow

0x05

Value of: 1, 2, 4, 8, 16, 32, 64, 128

0x10

AccuracyFilterFast

0x06

Value of: 1-8

0x02

AccuracyFilterSlow

0x07

Value of: 1-8

0x08

SpeedThreshold

0x08

Value of: 0-255

0x04

SleepDelay

0x0A

Value of: 0-255

0x64

PenUpDelay

0x0B

Value of: 0-255

0x80

TouchMode

0x0C

PD2

PD1

PD0

PM1

PM0

PU2

PU1

PU0

0xB1

TouchOptions

0x0D

–

–

–

–

–

–

48W

CCE

0x00

CalibrationInset

0x0E

Value of: 0-40

0x19

PenStateReportDelay

0x0F

Value of: 0-255

0xC8

TouchReportDelay

0x11

Value of: 0-255

0x00

Table 8 : Configuration Registers

Configuration registers are defined as an Offset value from the Start address for the register group.

To read or write to a register, do the following.

1) Issue the <Register Start Address Request> command to obtain the Start address for the register group.

2) Calculated the desired register’s absolute address by adding the register’s Offset value to Start address for

the register group.

3) Issue the <Register Read> or <Register Write> command, using the calculated register’s absolute address.

7.12.1 TouchThreshold Register (offset 0x02)

The TouchThreshold register sets the threshold for a touch condition to be detected as a touch. A touch is

detected if it is below the TouchThreshold setting. Too small of a value might prevent the controller from

accepting a real touch, while too large of a value might allow the controller to accept very light or false touches

conditions. Valid values are as follows.

0 ≤ TouchThreshold ≤ 255

7.12.2 SensitivityFilter Register (offset 0x03)

The SensitivityFilter register sets the level of touch sensitivity. A higher value is more sensitive to a touch

(accepts a lighter touch), but may exhibit a less stable touch position. A lower value is less sensitive to a touch

(requires a harder touch), but will provide a more stable touch position. Valid values are as follows.

0 ≤ SensitivityFilter ≤ 255

Warning: Use of invalid register value will yield unpredictable results!