Figure 3-6. Byte Write Cycle Flowchart; Figure 3-7. Word And Byte Write Cycle Timing Diagram - Motorola MC68306 User Manual

BUS MASTER
ADDRESS THE DEVICE
1) PLACE FUNCTION CODE ON FC2–FC0
2) PLACE ADDRESS ON ADDRESS BUS
3) ASSERT ADDRESS STROBE (AS)
4) SET R/W TO WRITE
5) PLACE DATA ON D0–D7 OR D15–D8
(ACCORDING TO INTERNAL A0)
6) ASSERT UPPER DATA STROBE (UDS)
OR LOWER DATA STROBE (LDS)
(BASED ON INTERNAL A0)
TERMINATE OUTPUT TRANSFER
1) NEGATE UDS AND LDS
2) NEGATE AS
3) REMOVE DATA FROM D7-D0 OR
D15-D8
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
A31–A1
*
A0
AS
UDS
LDS
R/W
DTACK
D15–D8
D7–D0
*INTERNAL SIGNAL ONLY

Figure 3-7. Word and Byte Write Cycle Timing Diagram

3-6

Figure 3-6. Byte Write Cycle Flowchart

WORD WRITE
MC68306 USER'S MANUAL
1) DECODE ADDRESS
2) LATCH DATA ON D7–D0 IF LDS IS
ASSERTED. LATCH DATA ON D15–D8
IF UDS IS ASSERTED
3) ASSERT DATA TRANSFER
ACKNOWLEDGE (DTACK)
1) NEGATE DTACK
ODD BYTE WRITE
SLAVE
INPUT THE DATA
TERMINATE THE CYCLE
EVEN BYTE WRITE
MOTOROLA