Motorola M68000 User Manual page 42

BUS MASTER
ADDRESS THE DEVICE
1) PLACE FUNCTION CODE ON FC2–FC0
2) PLACE ADDRESS ON A23–A0
3) ASSERT ADDRESS STROBE (AS)
4) SET R/W TO WRITE
5) PLACE DATA ON D0–D7
6) ASSERT LOWER DATA STROBE (LDS)
OR DS
TERMINATE OUTPUT TRANSFER
1) NEGATE LDS OR DS
2) NEGATE AS
3) REMOVE DATA FROM D7-D0
4) SET R/W TO READ
START NEXT CYCLE
S0 S1 S2 S3 S4 S5 S6 S7 S0 S1 S2 S3 S4 S5 S6 S7 S0 S1 S2 S3 S4 S5 S6 S7
CLK
FC2–FC0
A23–A0
AS
LDS
R/W
DTACK
D7–D0
ODD BYTE WRITE
4-4 M68000 8-/16-/32-BIT MICROPROCESSORS USER'S MANUAL
Freescale Semiconductor, Inc.
Figure 4-3. Byte Write-Cycle Flowchart
ODD BYTE WRITE
Figure 4-4. Write-Cycle Timing Diagram
For More Information On This Product,
Go to: www.freescale.com
SLAVE
INPUT THE DATA
1) DECODE ADDRESS
2) STORE DATA ON D7–D0
3) ASSERT DATA TRANSFER
ACKNOWLEDGE (DTACK)
TERMINATE THE CYCLE
1) NEGATE DTACK
EVEN BYTE WRITE
MOTOROLA