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Spi interface, At8xc51snd1c – Rainbow Electronics AT89C51SND1C User Manual

Page 190

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190

AT8xC51SND1C

4109E–8051–06/03

Waveforms

Figure 144. External IDE 16-bit Bus Cycle - Data Read Waveforms

Note:

1. D15:8 is written in DAT16H SFR.

Figure 145. External IDE 16-bit Bus Cycle - Data Write Waveforms

Note:

1. D15:8 is the content of DAT16H SFR.

SPI Interface

Definition of Symbols

Table 165. SPI Interface Timing Symbol Definitions

T

AVDV

T

LLAX

T

RHDX

T

RHDZ

T

AVLL

T

AVRL

P2

P0

RD

ALE

T

LHLL

T

RLRH

Data In

T

RLAZ

T

LLRL

T

RHLH

T

RLDV

D7:0

A7:0

Data In

D15:8

(1)

A15:8

T

WHLH

T

AVWL

T

LLAX

T

WHQX

P2

P0

WR

ALE

T

LHLL

T

WLWH

T

AVLL

T

QVWH

D7:0

Data Out

T

LLWL

A7:0

D15:8

(1)

Data Out

A15:8

Signals

Conditions

C

Clock

H

High

I

Data In

L

Low

O

Data Out

V

Valid

X

No Longer Valid

Z

Floating