State Transition Flow - NEC VR4181 mPD30181 User Manual

14.4 State Transition Flow

Be sure to initialize the PIU before scan sequencer operation. Initialization via a reset sets particular values for
the sequence interval, etc., which should be re-set to appropriate values.
The following registers require initial settings.
SCANINTVAL(10:0) bit of PIUSIVLREG register
STABLE(5:0) bit of PIUSTBLREG register
Interrupt mask cancellation settings are required for registers other than the PIU registers.
Setting
Interrupt mask clear
Clock mask clear
(1) Transition flow for voltage detection at A/D general-purpose ports and audio input port
Standby, WaitPenTouch, or Interval state
<1> PIUAMSKREG
<2> PIUASCNREG
↓
ADPScan state
<3> PIUASCNREG
↓
Standby, WaitPenTouch, or Interval state
(2) Transition flow for auto scan coordinate detection
Standby state
<1> PIUCNTREG
<2> PIUCNTREG
↓
WaitPenTouch state
CHAPTER 14 TOUCH PANEL INTERFACE UNIT (PIU)
Table 14-7. Mask Clear During Scan Sequencer Operation
Unit
ICU
ICU
MBA Host Bridge
Mask setting for A/D ports and audio input port
ADPSSTART = 1
ADPSSTART = 0
PIUMODE(1:0) = 00
PADATSTART = 1
PADATSTOP = 1
PIUSEQEN = 1
User's Manual U14272EJ3V0UM
Register Bit
MSYSINT1REG MPIUINTR
MPIUINTREG bits 6 to 0
CMUCLKMSK MSKPIUPCLK
Value
1
0x7F
1
295