Holtek HT32F54231 User Manual page 552

32-Bit Arm ® Cortex ® -M0+ MCU
HT32F54231/HT32F54241/HT32F54243/HT32F54253
Touch Key Auto Scan Operation Start
Time Slot &
No
16-bit C/F Counter
keep counting
Figure 202. Touch Key Auto Scan Mode Flowchart – TKMOD[1:0] = 00
Rev. 1.00
Start
Write Ref. OSC internal
Capacitor value
to the TKMnRO_Km bit field
Set Start bit TKST 0 → 1
 Busy flag TKBUSY = 1
Load Ref. OSC internal
Capacitor value from
the TKMnRO_Km bit field
Store C/F counter value to
the TKMn16D_Km bit field
Initiate Time Slot &
16-bit C/F Counter
All Time Slot counter &
16-bit C/F counter
start to count
All Time Slot
Counter overflow ?
Yes
No
All key scan finish ?
Yes
552 of 576
Touch key busy flag
TKBUSY = 0
TKRCOV = 1
Generate Interrupt
request flag
Touch key scan end
Set TKST 1 → 0
Read C/F counter value from
the TKMn16D_Km bit field
Change
next key
End
January 28, 2022