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Rev. 1.00
118
October 26, 2018
Rev. 1.00
119
October 26, 2018
BS86DH12C
High Voltage Touch A/D Flash MCU with HVIO
BS86DH12C
High Voltage Touch A/D Flash MCU with HVIO
Bit 0
MnK1EN
: Touch key module n Key 1 enable control
MnK1EN
Touch Key Module n – Mn
M0
M1
M2
0: Disable
I/O or other functions
1: Enable
KEY1
KEY5
KEY9
Touch Key Operation
When a finger touches or is in proximity to a touch pad, the capacitance of the pad will increase.
By using this capacitance variation to change slightly the frequency of the internal sense oscillator,
touch actions can be sensed by measuring these frequency changes. Using an internal programmable
divider the reference clock is used to generate a fixed time period. By counting a number of
generated clock cycles from the sense oscillator during this fixed time period touch key actions can
be determined.
TKST
MnKOEN
MnROEN
KEY OSC CLK
Reference OSC CLK
f
CFTMCK
Enable
f
CFTMCK
(MnDFEN=0)
f
CFTMCK
(MnDFEN=1)
TKRCOV
Cleared by hardware
Set Touch Key interrupt request flag
Time slot counter overflow time
Touch Key Scan Mode Timing Diagram
Each touch key module contains four touch key inputs which are shared with logical I/O pins, and
the desired function is selected using register bits. Each touch key has its own independent sense
oscillator. Therefore, there are four sense oscillators within each touch key module.
During this reference clock fixed interval, the number of clock cycles generated by the sense
oscillator is measured, and it is this value that is used to determine if a touch action has been made
or not. At the end of the fixed reference clock time interval a Touch Key interrupt signal will be
generated.
Using the TSCS bit in the TKC0 register can select the module 0 time slot counter as the time slot
counter for all modules. All modules use the same started signal, TKST, in the TKC0 register. The
touch key module 16-bit C/F counter, touch key function 16-bit counter, 5-bit time slot unit period
counter in all modules will be automatically cleared when the TKST bit is cleared to zero, but the
8-bit programmable time slot counter will not be cleared. The overflow time is set by user. When the
TKST bit changes from low to high, the 16-bit C/F counter, touch key function 16-bit counter, 5-bit
time slot unit period counter and 8-bit time slot timer counter will be automatically switched on.
The key oscillator and reference oscillator in all modules will be automatically stopped and the 16-bit
C/F counter, touch key function 16-bit counter, 5-bit time slot unit period counter and 8-bit time slot