Holtek BS66F340 - Touch Key Operation

Rev. 1.60 192 August 20, 2019 Rev. 1.60 193 August 20, 2019
BS66F340/BS66F350/BS66F360/BS66F370
Touch A/D Flash MCU with LED Driver
BS66F340/BS66F350/BS66F360/BS66F370
Touch A/D Flash MCU with LED Driver
• TKMnC2 Register
Bit 7 6 5 4 3 2 1 0
Name MnSK31 MnSK30 MnSK21 MnSK20 MnSK11 MnSK10 MnSK01 MnSK00
R/W R/W R/W R/W R/W R/W R/W R/W R/W
POR 1 1 1 0 0 1 0 0
Bit 7~6 MnSK31~MnSK30: Touch key module n time slot 3 key scan select
00: KEY 1
01: KEY 2
10: KEY 3
11: KEY 4
These bits are used to select the desired scan key in time slot 3 and only available in
the auto scan mode.
Bit 5~4 MnSK21~MnSK20: Touch key module n time slot 2 key scan select
00: KEY 1
01: KEY 2
10: KEY 3
11: KEY 4
These bits are used to select the desired scan key in time slot 2 and only available in
the auto scan mode.
Bit 3~2 MnSK11~MnSK10: Touch key module n time slot 1 key scan select
00: KEY 1
01: KEY 2
10: KEY 3
11: KEY 4
These bits are used to select the desired scan key in time slot 1 and only available in
the auto scan mode.
Bit 1~0 MnSK01~MnSK00: Touch key module n time slot 0 key scan select
00: KEY 1
01: KEY 2
10: KEY 3
11: KEY 4
These bits are used to select the desired scan key in time slot 0 in the auto scan mode
or used as the multiplexer for scan key select in the manual mode.
Touch Key Operation
When a nger 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 xed time period touch key actions can
be determined.