Touch Key Data Memory - Holtek BS83A04C Manual

In the periodic auto scan mode the touch key scan operation will be implemented automatically on
a periodic basis, which can be determined by the ASMP1~ASMP0 bits in the TKC2 register. The
number of touch key scan times depends upon the WDT time-out period and the periodic auto scan
mode period. Each auto scan operation will sequentially be carried out in a specific way from time
slot 0 to time slot 3 like the auto scan mode. The reference oscillator internal capacitor value for each
time slot selected key will be read from the touch key data memory and loaded into the TKM0ROH/
TKM0ROL registers. However, only at the end of the last scan operation in the WDT time-out cycle,
the 16-bit C/F counter value for all scanned keys will be written into the corresponding touch key
data memory.
In addition, the 16 bit upper/lower threshold value for the selected key to be scanned in the time slot
0 will be read from a specific location of the dedicated touch key data memory and loaded into the
corresponding TKM0TH16H/TKM0TH16L registers before the selected key will start to be scanned
in time slot 0. The TKM0TH16H/TKM0TH16L register pair will be loaded with the corresponding
next time slot 16-bit upper/lower threshold value from the dedicated touch key data memory
automatically by the hardware at the end of the current time slot when the periodic auto scan mode is
selected. each touch key has its own independent upper/lower threshold comparaor. The upper/lower
threshold comparison function will automatically be enabled in the periodic auto scan mode. When
any key C/F counter value is less than the lower threshold if M0KnTHS=0, or larger than the upper
threshold if M0KnTHS=1, this indicates that the touch key state changes, then the M0KnTHF flag
will be set high by the hardware, and an interrupt signal will be generated. Note that if the touch key
threshold TKTH interrupt occurs, 1-byte data will be written to the TKM0ROL register because the
TKM0ROH/TKM0ROL register pair will be loaded with the corresponding next time slot capacitor
value from the dedicated touch key data memory and the 16-bit C/F counter content, TKM016DH/
TKM016DL, and the TKM0TH16H/TKM0TH16L value are compared at the same time.
As the periodic auto scan operation is implemented using the WDT counter clock to reduce power
consumption, when the WDT is cleared the WDT counter will be reset, the periodic auto scan
operation time will be affected but the number of touch key times will not be affected.

Touch Key Data Memory

The device provides three dedicated Data Memory area. The first area is used to store the 16-bit C/
F counter values of the touch key module and located in Data Memory Sector 5, The second area is
used to store the reference oscillator internal capacitor values of the touch key module and located
in Data Memory Sector 6. The last area is used to store the 16-bit upper/lower threshold value of the
touch key module and located in Data Memory Sector 7.
TKM016DL / TKM016DH
16-bit C/F counter
TKM0ROL / TKM0ROH
10-bit Ref. OSC capacitor
M0KnTHS Comparetor
Upper/Low side
threshold Register
TKM0TH16H/TKM0TH16L
Note: n=Touch Key number, 1~4.
Rev. 1.00
4-Key Enhanced Touch I/O Flash MCU
16-bit C/F counter value
(Sector 5)
00H TKM016DL_K1
01H TKM016DH_K1
02H TKM016DL_K2
TKM016DH_K2
Module 0
TKM016DL_K3
TKM016DH_K3
TKM016DL_K4
TKM016DH_K4
07H
TKTH
Touch Key Register Memory Map
76
BS83A04C
Upper/Low SIde Threshold VAlue
Ref. OSC Capacitor value
(Sector 6)
(Sector 7)
TKM0ROL_K1 TKM0TH16L_K1
TKM0ROH_K1 TKM0TH16H_K1
TKM0ROL_K2 TKM0TH16L_K2
TKM0ROH_K2 TKM0TH16H_K2
TKM0TH16L_K3
TKM0ROL_K3
TKM0TH16H_K3
TKM0ROH_K3
TKM0TH16L_K4
TKM0ROL_K4
TKM0ROH_K4 TKM0TH16H_K4
March 24, 2020