AR1020T-I/SS Microchip Technology, AR1020T-I/SS Datasheet - Page 21

• Manufacturer Part Number: AR1020T-I/SS
• Description: IC TOUCH SCREEN CTRLR 20-SSOP
• Manufacturer: Microchip Technology
• Type: Resistiver

Specifications of AR1020T-I/SS

• Package / Case: 20-SSOP
• Touch Panel Interface: 4-Wire, 5-Wire, 8-Wire
• Number Of Inputs/keys: 3 Key
• Resolution (bits): 10 b
• Data Interface: I²C, Serial, SPI™
• Voltage - Supply: 3.3 V ~ 5.5 V
• Current - Supply: 17mA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Voltage Supply Source: Single Supply
• Supply Voltage Range: 3.135V To 3.465V, 4.75V To 5.25V
• Operating Temperature Range: -40°C To +85°C
• Digital Ic Case Style: TSSOP
• No. Of Pins: 20
• Svhc: No SVHC (15-Dec-2010)
• Supply: RoHS Compliant
• Ic Function: Touch Screen Controller
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Sampling Rate (per Second): -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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.


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.
The format for sending commands is:
© 2009 Microchip Technology, Inc.
SamplingFast (offset 0x04)
AccuracyFilterFast (offset 0x06)
1) Send Disable Touch command
2) Wait 50ms
3) Send desired command/s
4) Send Enable Touch command
<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.
= 8
= 8
<Header><DataSize><Command><Data>…<Data>
DS41393A-Page 17