EM78P468LAQ EMC [ELAN Microelectronics Corp], EM78P468LAQ Datasheet - Page 44

• Manufacturer Part Number: EM78P468LAQ
• Description: 8-BIT Microcontroller
• Manufacturer: EMC [ELAN Microelectronics Corp]

EM78P468L
8-BIT Microcontroller
40 •
4.8 Interrupt
This LSI has eight interrupt sources as listed below:
This IC has internal interrupts which are falling edge triggered or as follows :
If these interrupt sources change signal from high to low, the RF register will generate “1”
flag to corresponding register if the IOCF0 register is enabled.
RF is the interrupt status register. It records the interrupt request in flag bit. IOCF0 is the
interrupt mask register. Global interrupt is enabled by ENI instruction and disabled by
DISI instruction. When one of the interrupts (when enabled) is generated, it will cause the
next instruction to be fetch from address 0003H~0018H according to interrupt source.
With this LSI, each individual interrupt source has its own interrupt vector as depicted in
Table 3. Before the interrupt subroutine is executed, the contents of ACC and the R3
register are initially saved by hardware. After the interrupt service routine is completed,
ACC and R3 are restored. The existing interrupt service routine does not allow other
interrupt service routine to be executed. So if other interrupts occur while the existing
interrupt service routine is being executed, the hardware will save the later interrupts.
Only after the existing interrupt service routine is completed that the next interrupt
service routine is executed.
TCC overflow interrupt.
External interrupt P5.4/INTO pin
External interrupt P5.5/INT1 pin
Counter 1 underflow interrupt
Counter 2 underflow interrupt
High-pulse width timer underflow interrupt
Low-pulse width timer underflow interrupt
Port 6, Port 8 input status change wake-up
TCC timer overflow interrupt,
Four 8-bits down counter/timer underflow interrupt
Fig. 14 Circuit 2 for the Residue Voltage Protection
(This specification is subject to change without further notice)
Product Specification (V1.0) 03.15.2006