HT68F14 HOLTEK [Holtek Semiconductor Inc], HT68F14 Datasheet - Page 115

• Manufacturer Part Number: HT68F14
• Description: Enhanced I/O Flash Type MCU
• Manufacturer: HOLTEK [Holtek Semiconductor Inc]

Rev. 1.10
Multi-function Interrupt
Time Base Interrupts
Within these devices there are up to six Multi-function interrupts. Unlike the other independent
interrupts, these interrupts have no independent source, but rather are formed from other existing
interrupt sources, namely the TM Interrupts.
A Multi-function interrupt request will take place when any of the Multi-function interrupt request
flags, MF0F~MF1F are set. The Multi-function interrupt flags will be set when any of their included
functions generate an interrupt request flag. To allow the program to branch to its respective interrupt
vector address, when the Multi-function interrupt is enabled and the stack is not full, and either one of
the interrupts contained within each of Multi-function interrupt occurs, a subroutine call to one of the
Multi-function interrupt vectors will take place. When the interrupt is serviced, the related
Multi-Function request flag, will be automatically reset and the EMI bit will be automatically cleared
to disable other interrupts.
However, it must be noted that, although the Multi-function Interrupt flags will be automatically reset
when the interrupt is serviced, the request flags from the original source of the Multi-function
interrupts, namely the TM Interrupts, will not be automatically reset and must be manually reset by the
application program.
The function of the Time Base Interrupt is to provide regular time signal in the form of an internal
interrupt. It is controlled by the overflow signal from the respective timer function. When this happens,
the respective interrupt request flags TBF 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 bit
TBE 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 TBF will be automatically reset and the EMI bit will be cleared to
disable other interrupts.
The purpose of the Time Base Interrupt is to provide an interrupt signal at fixed time periods. Their
clock sources originate from the internal clock source fTB. This fTB input clock passes through a
divider, the division ratio of which is selected by programming the appropriate bits in the TBC register
to obtain longer interrupt periods whose value ranges. The clock source that generates fTB, which in
turn controls the Time Base interrupt period, can originate from several different sources, as shown in
the System Operating Mode section.
Note: The f
TBC
is from the LIRC oscillator.
Time Base Interrupt
115
Enhanced I/O Flash Type MCU
HT68F13/HT68F14/HT68F15
February 9, 2011