
CHAPTER 9
PIU (TOUCH PANEL INTERFACE UNIT)
User’s Manual U14579EJ2V0UM
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(4) CmdScan state
When in this state, the A/D converter operates using various settings. Voltage data from one port only is
fetched based on a combination of the touch panel I/O signal setting (TPX(1:0), TPY(1:0)) and the selection of
an input port (ADX, ADY, AUDIOIN, ADIN) connected to the A/D converter. Use PIUCMDREG register to
make the touch panel pin setting and to select the input port.
(5) WaitPenTouch state
This is the standby state that waits for a touch panel “Touch” state. When the PIU detects a touch panel
“Touch” state, a touch panel contact status change interrupt occurs inside the PIU. At this point, if the
PADATSTART bit is active, the state changes to the PenDataScan state.
In the WaitPenTouch state, it is possible to change to Suspend mode, however, the PCICLK stops and panel
status detection is not performed.
(6) PenDataScan state
This is the state in which touch panel coordinates are detected. The A/D converter is activated and the four
sets of data for each coordinate are sampled.
Caution
If one complete pair of coordinates is not obtained during the interval between one pair of
coordinates and the next coordinate data, a data lost interrupt occurs inside the PIU.
(7) IntervalNextScan state
This is the standby state that waits for the next coordinate sampling period and the touch panel’s “Release”
state. After the touch panel state is detected, the time period specified via PIUSIVLREG register elapses
before the transition to the PenDataScan state. If the PIU detects the “Release” state within the specified time
period, a touch panel contact status change interrupt occurs inside the PIU. At this point, the state changes to
the WaitPenTouch state if the PADATSTOP bit is active. If the PADATSTOP bit is inactive, it changes to the
PenDataScan state after the specified time period has elapsed.