Interrupts - Holtek HT66F20 Manual

Interrupts

Interrupts are an important part of any microcontroller system. When an external event or an
internal function such as a Timer Module or an A/D converter requires microcontroller attention,
their corresponding interrupt will enforce a temporary suspension of the main program allowing the
microcontroller to direct attention to their respective needs. The device contains several external
interrupt and internal interrupts functions. The external interrupts are generated by the action of the
external INT0~INT3 and PINT pins, while the internal interrupts are generated by various internal
functions such as the TMs, Comparators, Time Base, LVD, EEPROM, SIM and the A/D converter.
Interrupt Registers
Overall interrupt control, which basically means the setting of request flags when certain
microcontroller conditions occur and the setting of interrupt enable bits by the application program,
is controlled by a series of registers, located in the Special Purpose Data Memory, as shown in the
accompanying table. The number of registers depends upon the device chosen but fall into three
categories. The first is the INTC0~INTC3 registers which setup the primary interrupts, the second
is the MFI0~MFI3 registers which setup the Multi-function interrupts. Finally there is an INTEG
register to setup the external interrupt trigger edge type.
Each register contains a number of enable bits to enable or disable individual registers as well as
interrupt flags to indicate the presence of an interrupt request. The naming convention of these
follows a specific pattern. First is listed an abbreviated interrupt type, then the (optional) number of
that interrupt followed by either an "E" for enable/disable bit or "F" for request flag.
Rev. 2.50
HT66F20/HT66F30/HT66F40/HT66F50/HT66F60
HT66FU30/HT66FU40/HT66FU50/HT66FU60
Function Enable Bit
Global EMI
Comparator CPnE
INTn Pin INTnE
A/D Converter ADE
M�lti-f�nction MFnE
Time Base TBnE
SIM SIME
LVD LVE
EEPROM DEE
PINT Pin XPE
TnPE
TM TnAE
TnBE
Interrupt Register Bit Naming Conventions
202
A/D Flash MCU with EEPROM
Request Flag Notes
— —
CPnF n=0 or �
INTnF n=0~3
ADF —
MFnF n=0~5
TBnF n=0 or �
SIMF —
LVF —
DEF —
XPF —
TnPF
TnAF n=0~3
TnBF
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