Datasheet

AR1100 RESISTIVE USB AND RS-232 TOUCH SCREEN CONTROLLER
DS41606B-page 30  2011 Microchip Technology Inc.
7.2.3 EXECUTION
The host first commands the AR1100 to enter
Calibration mode, then subsequently presents the
calibration point targets, one at a time, from left to right,
top to bottom. The AR1100 returns a calibration
command response packet each time the operator
touches a target – signaling the host to proceed. Upon
completion, the data from the calibration process is
saved to EEPROM and available for use by the
AR1100 during normal operation. Calibration process
can be aborted by the host by simply issuing any
command. That command will be ignored but the
response to that command will have a status byte that
indicates that calibration had terminated prematurely
(see below).
7.2.3.1 Normal sequence
• host issues calibration command: <0x55>
<0x02> <0x14> <type>
• host present 1
st
target
• operator touches (and releases) sensor at 1
st
target
• device issues response packet: <0x55> <0x02>
<0x00> <0x14>
• host presents 2
nd
target
• operator touches (and releases) sensor at 2
nd
target
• device issues response packet: <0x55> <0x02>
<0x00> <0x14>
•…
• host presents last target
• operator touches (and releases) sensor at last
target
• device issues response packet: <0x55> <0x02>
<0x00> <0x14>
• host terminates the target display
• device returns to normal operation
7.2.3.2 Aborted sequence
• host issues calibration command: <0x55>
<0x02> <0x14> <type>
• host presents 1
st
target
• operator touches (and releases) sensor at 1
st
target
• device issues response packet: <0x55> <0x02>
<0x00> <0x14>
• host presents 2
nd
target
• operator touches (and releases) sensor at 2
nd
target
• device issues response packet: <0x55> <0x02>
<0x00> <0x14>
•host issues TOUCH_ENABLE command to abort
calibration: <0x55> <0x01> <0x12>
• device issues response packet: <0x55> <0x02>
<0xFC> <0x12>
• (status 0xFC indicates calibration termination)
• host terminates the target display
• device returns to normal operation
7.2.3.3 Normal sequence (verbose)
The VCF (Verbose Calibration Feedback) bit in the
TouchOptions Configuration register enables ‘verbose’
communication from the AR1100 in Calibration mode
as evidenced below:
• host sets ‘verbose’ flag in Configuration register
i.e., TouchOptions[VCF]
• host issues calibration command: <0x55>
<0x02> <0x14> <type>
• device responds: <0x55> <0x07> <0x00>
<0x14> <0xFE> <0xXX> <0xXX> <0xYY>
<0xYY>
0xFE indicates ‘enter’ Calibration mode, XX and YY are
don’t care.
• host presents 1
st
target
• operator touches (and releases) sensor at 1
st
target
• device issues response packet: <0x55> <0x07>
<0x00> <0x14> <0x00> <0xXX> <0xXX>
<0xYY> <0xYY>
•the 5
th
byte indicates the calibration point 0x00
(the 1
st
)
0xXXXX and 0xYYYY are RAW coordinates of the
touch point (16-bit, little endian)
• host presents 2
nd
target
• operator touches (and releases) sensor at 2
nd
target
• device issues response packet: <0x55> <0x07>
<0x00> <0x14> <0x01> <0xXX> <0xXX>
<0xYY> <0xYY>
•The 5
th
byte indicates the calibration point 0x01
(the 2
nd
)
0xXXXX and 0xYYYY are RAW coordinates of the
touch point (16-bit, little endian)
…