© 2009 Microchip Technology, Inc.

DS41393A-Page 17

7.12.13 PenStateReportDelay Register (offset 0x0F)

The PenStateReportDelay register sets the delay time between sending of sequential touch reports for the “Pen

Down” and “Pen Up” touch mode states. See TouchMode Register section for touch modes.

For example, if “Pen Up” state of the TouchMode register is configured to send a touch report with P=1, followed

by a touch report with P=0, then this delay occurs between the two touch reports. This provides some timing

flexibility between the two touch reports that may be desired is certain applications. Valid values are as follows.

0 ≤ PenStateReportDelay ≤ 255

Pen State Report Delay Time = PenStateReportDelay * 50μs

7.12.14 TouchReportDelay Register (offset 0x11)

The TouchReportDelay register sets a forced delay time between successive touch report packets. This allows

slowing down of the touch report rate, if desirable for a given application. For example, a given application may

not need a high rate of touch reports and may want to reduce the overhead used to service all of the touch reports

being sent. In this situation, increased the value of this register will reduce the rate at which the controller sends

touch reports. Valid values are as follows.

0 ≤ TouchReportDelay ≤ 255

Touch Report Delay Time ≈ TouchReportDelay * 500μs

7.12.15 User Configuration – Spiking

If the reported touch position contains some spiking position errors, then this can be improved by changing the

following Configuration Register values.



SamplingFast (offset 0x04)

= 8



AccuracyFilterFast (offset 0x06)

= 8

The trade off with the above change is that the touch report rate (points per second) will be decreased. This is

fine for many applications.

7.13 Command Format

The controller supports application specific configuration commands.

To ensure command communication is not interrupted by touch activity, it is recommended that the controller

touch is disabled, prior to other commands. This can be done as follows.

1) Send Disable Touch command

2) Wait 50ms

3) Send desired command/s

4) Send Enable Touch command

The format for sending commands is:

<Header><DataSize><Command><Data>…<Data>

<Header> is defined as a value of 0x55 and is used to mark the beginning of the command packet.

<DataSize> is the number of bytes being sent in the command packet, after <DataSize>.

<Command> is a value assigned to a specific command.

<Data> represent from zero to eight bytes of command specific data.