Holtek BS83B24C Manual page 158

Touch Key Interrupt
An Touch Key Interrupt request will take place when the Touch Key Interrupt request flag, TKMF,
is set, which occurs when the touch key time slot counter overflows. To allow the program to branch
to its respective interrupt vector address, the global interrupt enable bit, EMI, and the Touch Key
Interrupt enable bit, TKME, must first be set. When the interrupt is enabled, the stack is not full
and the touch key time slot counter overflows, a subroutine call to the Touch Key Interrupt vector,
will take place. When the Touch Key Interrupt is serviced, the TKRMF flag will be automatically
cleared, the EMI bit will also be automatically cleared to disable other interrupts.
Time Base Interrupts
The function of the Time Base Interrupts is to provide regular time signal in the form of an internal
interrupt. They are controlled by the overflow signals from their respective timer functions. When
these happens their respective interrupt request flags, TBnF, will be set. To allow the program to
branch to their respective interrupt vector addresses, the global interrupt enable bit, EMI, and Time
Base enable bits, TBnE, must first be set. When the interrupt is enabled, the stack is not full and the
Time Base overflows, a subroutine call to their respective vector locations will take place. When the
interrupt is serviced, the respective interrupt request flag, TBnF, will be automatically cleared, the
EMI bit will also be automatically cleared to disable other interrupts.
The purpose of the Time Base Interrupt is to provide an interrupt signal at fixed time periods.
Its clock source, f
through a divider, the division ratio of which is selected by programming the appropriate bits in the
TBnC registers to obtain longer interrupt periods whose value ranges. The clock cource which in
turn controls the Time Base interrupt period is selected using the CLKSEL[1:0] bits in the PSCR
register.
f
SYS
M
f
f /4 U
SYS
X
f
SUB
CLKSEL[1:0]
• PSCR Register
Bit 7
Name —
R/W —
POR —
Bit 7~2 Unimplemented, read as "0"
Bit 1~0 CLKSEL1~CLKSEL0: Prescaler clock source selection
00: f
01: f
1x: f
Rev. 1.00
, originates from the internal clock source f
PSC
TB0ON
�
f /� ~ f /�
PSC PSC
PSC
P�escale�
�
f /� ~ f /�
PSC PSC
TB1ON
Time Base Interrupts
6 5
— —
— —
— —
SYS
/4
SYS
SUB
15�
BS83B24C/BS83C40C
Touch Flash MCU
, f /4 or f
SYS SYS
M
15
Time Base 0 Inte���pt
U
X
TB0[�:0]
15
M
Time Base 1 Inte���pt
U
X
TB1[�:0]
4 3 2
— — — CLKSEL1 CLKSEL0
— — —
— — —
and then passes
SUB
1 0
R/W R/W
0 0
�e���a�� 0�� �01�