Z8018110FEC View Datasheet(PDF) - Zilog

Part Name

Description

View to exact match

Z8018110FEC

SMART ACCESS CONTROLLER (SAC™)

Zilog 

Zilog

SYSTEM CONTROL SIGNALS

Pin Name

ST

Pin Number

3

Input/Output, Tri-State

Out, Active 1

Z80181

SMART ACCESS CONTROLLER SAC™

Function

Status. This signal is used with the /M1 and /HALT output

to decode the status of the CPU machine cycle. Note that

the /M1 output is affected by the status of the M1E bit in the

OMCR register. The following table shows

the status while M1E=1.

ST /HALT /M1

0

1

0

1

1

0

1

1

1

0

X

1

0

0

0

1

0

1

Operation

CPU Operation

(1st Opcode fetch)

CPU Operation

(2nd and 3rd Opcode fetch)

CPU Operation

(MC other than Opcode fetch)

DMA operation

HALT mode

SLEEP mode

(Incl. System STOP mode)

2-10

DS971800500

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