Z80180 Datasheet, PDF (92/326 Pages) Zilog, Inc. – Z8018x Family MPU

Z 8018x Fam ily
M PU Us e r M anual
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
Main
Program
0 → EF1, EF2
PCH → (SP-1)
0038H
PCL → (SP-2)
INT0
(Mode 1)
PCL ← (SP)
PCH ← (SP+1)
INT0 (Mode 1)
Interrupt Service
Program
E1 (1 → 1EF1, 1EF2)
RETI
Figure 38 illustrates INT0 Mode 1 Timing.
UM005001-ZMP0400