em78f644nso28s ELAN Microelectronics Corp, em78f644nso28s Datasheet - Page 155

• Manufacturer Part Number: em78f644nso28s
• Description: Flash Series 8-bit Microcontroller
• Manufacturer: ELAN Microelectronics Corp

Product Specification (V1.0) 05.05.2010
(This specification is subject to change without further notice)
RE and RF are the Interrupt Status registers that record the interrupt requests in the
relative flags/bits. IOCE and IOCF are the Interrupt Mask registers. The global
interrupt is enabled by the ENI instruction and is disabled by the DISI instruction.
When one of the enabled interrupts occurs, the next instruction will be fetched from
their individual address. The interrupt flag bit must be cleared by instructions before
leaving the interrupt service routine and before interrupts are enabled to avoid
recursive interrupts.
The flag (except ICIF bit) in the Interrupt Status Register (RF and RE) is set
regardless of the status of its mask bit or the execution of ENI. The RETI instruction
ends the interrupt routine and enables the global interrupt (the execution of ENI).
The external interrupt is equipped with an on-chip digital noise rejection circuit (input
pulse of less than 8 system clock time is eliminated as noise), but in Low Crystal
oscillator (LXT) mode, the noise rejection circuit is disabled. When an interrupt
(Falling edge) is generated by the External interrupt (when enabled), the next
instruction will be fetched from Address 003H.
Before the interrupt subroutine is executed, the contents of ACC and the R3 & R4
registers are saved by hardware. If another interrupt occurs, the ACC, R3 and R4 will
be replaced by the new interrupt. After the interrupt service routine is completed,
ACC, R3, and R4 will be pushed back.
Internal /
External
External
External
Internal
External
Internal
Internal /
External
External
External
Internal
External
Internal
Internal
The EM78F642/542N has 6 interrupts (3 external, 3 internal) listed below:
The EM78F641/541N has 5 interrupts (3 external, 2 internal) as listed below:
Interrupt Source
Interrupt Source
Reset
INT
Port 6 pin change ENI +ICIE=1
TCC
Comparator2
TC2
TC3
Reset
INT
Port 6 pin change ENI +ICIE=1
TCC
Comparator 2
TC3
Enable Condition Int. Flag Int. Vector
Enable Condition Int. Flag Int. Vector
ENI + EXIE=1
ENI + TCIE=1
ENI+CMP2IE=1
ENI + TC3IE=1
-
ENI + EXIE=1
ENI + TCIE=1
ENI+CMP2IE=1
ENI + TCIE2=1
ENI + TCIE3=1
EM78F648/644/642/641/548/544/542/541N
-
EXIF
ICIF
TCIF
CMP2IF
TC3IF
-
EXIF
ICIF
TCIF
CMP2IF
TCIF2
TCIF3
-
8-Bit Microcontroller
0000
0003
0009
0015
0024
0027
0000
0003
0006
0009
0015
0027
0006
Priority
Priority
High 0
High 0
1
2
3
4
5
1
2
3
4
5
6
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