AR1020T-I/SS Microchip Technology, AR1020T-I/SS Datasheet - Page 20

• 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

7.12.11 TouchOptions Register (offset 0x0D)
The TouchOptions register contains various “touch” related option bits.
R = Readable bit, W = Writable bit, U = Unimplemented bit read as ‘0’
Bit 7
bit 7-2 Unimplemented: Read as ‘0’
bit 1
bit 0
7.12.12 CalibrationInset Register (offset 0x0E)
The CalibrationInset register defines the expected position of the calibration points, inset from the perimeter of the
touch sensor’s active area, by a percentage of the full scale dimension.
This allows for the calibration targets to be placed inset from edge to make it easier for a user to touch them.
The CalibrationInset register value is only used when the Calibration Mode command is issued to the controller.
In Calibration Mode, the controller will extrapolate the calibration point touch report values by the defined
CalibrationInset percentage to achieve full scale.
A software application that issues the Calibration Mode command must present the displayed calibration targets
at the same inset percentage as defined in this CalibrationInset register.
Valid values are as follows.
0 ≤ CalibrationInset ≤ 40
Calibration Inset = ( CalibrationInset / 2 ) % , Range of 0–20% with 0.5% resolution
For example, CalibrationInset = 25 (0x19) yields a calibration inset of (25 / 2) or 12.5%. During the calibration
procedure, the controller will internally extrapolate the calibration point touch values in Calibration Mode by 12.5%
to achieve full scale.
DS41393A-Page 16
A 4-wire touch sensor will not work if the 48W configuration bit is incorrectly defined as one, which
selects 8-wire.
An 8-wire touch sensor will provide basic operation if the 48W configuration bit is incorrectly defined
as zero, which selects 4-wire. However, the benefit of the 8-wire sensor will only be realized, if the
48W configuration bit is correctly defined as one, selecting 8-wire.
U–0
–
48W: 4-wire or 8-wire Sensor Selection bit
1 = Selects 8-wire sensor operating mode
0 = Selects 4-wire sensor operating mode
CCE: Calibrated Coordinates Enable bit
1 = Enables calibrated coordinates, if the controller has been calibrated
0 = Disables calibrated coordinates
Location of calibration
targets presented
during calibration.
U–0
–
12.5% of
Full Scale
U–0
–
12.5% of
Full Scale
U–0
–
U–0
–
U–0
–
48W
R/W
© 2009 Microchip Technology, Inc.
CCE
R/W
Bit 0