Z8018010FSC datasheet(49/124 Pages) ZILOG

49 / 124 page

Z 8018x Fam il

M PU Use r M anual

UM005001-ZMP0400

• Data Bus, 3-state

SLEEP mode is exited in one of two ways as described below.

• RESET Exit from SLEEP mode. If the RESET input is held Low for

at least six clock cycles, it exits SLEEP mode and begins the normal

RESET sequence with execution starting at address (logical and

physical) 00000H.

• Interrupt Exit from SLEEP mode. The SLEEP mode is exited by

detection of an external (NMI, INT0, INT2) or internal (ASCI,

CSI/O, PRT) interrupt.

In case of NMI, SLEEP mode is exited and the CPU begins the normal

NMI interrupt response sequence.

In the case of all other interrupts, the interrupt response depends on the

state of the global interrupt enable flag IEF1 and the individual interrupt

source enable bit.

If the individual interrupt condition is disabled by the corresponding

enable bit, occurrence of that interrupt is ignored and the CPU remains in

the SLEEP mode.

Assuming the individual interrupt condition is enabled, the response to

that interrupt depends on the global interrupt enable flag (IEF1). If

interrupts are globally enabled (IEF1 is 1) and an individually enabled

interrupt occurs, SLEEP mode is exited and the appropriate normal

interrupt response sequence is executed.

If interrupts are globally disabled (IEF1 is 0) and an individually enabled

interrupt occurs, SLEEP mode is exited and instruction execution begins

with the instruction following the SLP instruction. This feature provides a

technique for synchronization with high speed external events without

incurring the latency imposed by an interrupt response sequence.

Figure 21 depicts SLEEP timing.

Z8018010FSC Datasheet(PDF) 49 Page - Zilog, Inc.