HT45F3420 Datasheet, PDF (118/141 Pages) Holtek Semiconductor Inc – Personal Care Flash MCU

HT45F3420/HT45F3430
Personal Care Flash MCU
Multi-function Interrupt
Within the devices there is only one Multi-function interrupts. Unlike the other independent
interrupts, the interrupt has no independent source, but rather are formed from other existing
interrupt sources, namely the STM CCRA and CCRP interrupts.
A Multi-function interrupt request will take place when the Multi-function interrupt request flag,
MFF is set. The Multi-function interrupt flag 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 the Multi-function interrupt occurs, a subroutine call to the Multi-
function interrupt vector 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 flag will be automatically
reset when the interrupt is serviced, the request flags from the original source of the Multi-function
interrupts, namely the STM Interrupts, will not be automatically reset and must be manually reset by
the application program.
A/D Converter Interrupt
The devices contain an A/D converter which has its own independent interrupt. The A/D Converter
Interrupt is controlled by the termination of an A/D conversion process. An A/D Converter Interrupt
request will take place when the A/D Converter Interrupt request flag, ADF, is set, which occurs
when the A/D conversion process finishes. To allow the program to branch to its respective interrupt
vector address, the global interrupt enable bit, EMI, and A/D Interrupt enable bit, ADE, must first be
set. When the interrupt is enabled, the stack is not full and the A/D conversion process has ended, a
subroutine call to the A/D Converter Interrupt vector, will take place. When the interrupt is serviced,
the A/D Converter Interrupt flag, ADF, will be automatically cleared. The EMI bit will also be
automatically cleared to disable other interrupts.
Time Base Interrupt
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, TB0F or TB1F 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, TB0E or TB1E, 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, TB0F or TB1F, 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
which is selected using the TBCK bit in the TBC register.
Rev. 1.31
118
April 11, 2017