68000 データシートの表示（PDF） - Freescale Semiconductor

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68000

8-/16-/32-Bit Microprocessors User’s Manual

Freescale Semiconductor 

Freescale Semiconductor, Inc.

BUS MASTER

ADDRESS THE DEVICE

1) SET R/W TO READ

2) PLACE FUNCTION CODE ON FC2–FC0

3) PLACE ADDRESS ON A23-A0

4) ASSERT ADDRESS STROBE (AS)

5) ASSERT LOWER DATA STROBE (LDS)

(DS ON MC68008)

ACQUIRE THE DATA

1) LATCH DATA

2) NEGATE LDS (DS FOR MC68008)

3) NEGATE AS

START NEXT CYCLE

SLAVE

INPUT THE DATA

1) DECODE ADDRESS

2) PLACE DATA ON D7–D0

3) ASSERT DATA TRANSFER

ACKNOWLEDGE (DTACK)

TERMINATE THE CYCLE

1) REMOVE DATA FROM D7–D0

2) NEGATE DTACK

Figure 4-1. Byte Read-Cycle Flowchart

CLK

FC2–FC0

A23–A0

AS

(DS) LDS

S0 S1 S2 S3 S4 S5 S6 S7 S0 S1 S2 S3 S4 S5 S6 S7 S0 S1 S2 S3 S4 w w w w S5 S6 S7

R/W

DTACK

D7–D0

READ

WRITE

2 WAIT STATE READ

Figure 4-2. Read and Write-Cycle Timing Diagram

4-2

M68000 8-/16-/32-BIT MICROPROCESSORS USER'S MANUAL

MOTOROLA

For More Information On This Product,

Go to: www.freescale.com

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