VR4102 datasheet(385/701 Pages) NEC

385 / 701 page

CHAPTER 19 PIU (TOUCH PANEL INTERFACE UNIT)

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• 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 pin setting (TPX[1:0], TPY[1:0]) and the selection of an

input port (TPX[1:0], TPY[1:0], AUDIOIN, ADIN[2:0]) to the A/D converter. Use PIUCMDREG to make the

touch panel pin setting and to select the input port.

• WaitPenTouch state

This is the standby state that waits for a touch panel “touch” state. When the PIU detects a touch panel

“touch” state, PenChgIntr (an internal interrupt in the PIU) occurs. At this point, if the PADAUTOSCAN bit is

active, the state changes to the PenDataScan state. During the WaitPenTouch state, it is possible to change

to Suspend mode because the panel state can be detected even when TClock has been stopped.

• 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 PadDataLostIntr interrupt occurs.

• IntervalNextScan state

This is the standby state that waits for the next coordinate sampling period or a touch panel “release” state.

After the touch panel state is detected, the time period specified via PIUSIVLREG elapses before the

transition to the PenDataScan state. If the PIU detects a “release” state within the specified time period,

PenChgIntr (an internal interrupt in the PIU) occurs. 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.

VR4102 Datasheet(PDF) 385 Page - NEC