Zilog Z80180 - Manual (Page 92)

Z8018x
Family MPU User Manual
UM005003-0703
77
disabling all maskable interrupts. The interrupt service routine normally
terminates with the EI (Enable Interrupts) instruction followed by the
RETI (Return from Interrupt) instruction, to reenable the interrupts.
Figure 37 depicts the use of INT0 (Mode 1) and RETI for the Mode 1
interrupt sequence.
Figure 37. INT0 Mode 1 Interrupt Sequence
Figure 38 illustrates INT0 Mode 1 Timing.
INT0 (Mode 1)
Main
Program
0
PCH
PCL
PCL
PCH
Interrupt Service
Program
0038H
RETI
® (SP-2)
® (SP-1)
® EF1, EF2
¬ (SP)
¬ (SP+1) E1 (1 ® 1EF1, 1EF2)
INT0
(Mode 1)