EM78468
8-BIT Microcontroller
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.
InterruptOccur
InterruptSource
ENI/ DISI
ACC
R3
STACKACC
STACKR3
RETI
Fig. 15. Interrupt Backup Diagram
Table 3 Interrupt Vector
Interrupt Vector
0003H
Interrupt Status
TCC overflow interrupt.
0006H
0009H
000CH
External interrupt P5.4/INT0 pin
External interrupt P5.5/INT1 pin
Counter 1 underflow interrupt
000FH
Counter 2 underflow interrupt
0012H
0015H
High-pulse width timer underflow interrupt
Low-pulse width timer underflow interrupt
0018H
PORT 6, PORT 8 input status change wake-up
Product Specification (V1.1) 04.11.2005
• 41
(This specification is subject to change without further notice)
ELAN [ ELAN MICROELECTRONICS CORP ]
