MC68306FC16 Datasheet, PDF (37/191 Pages) Motorola, Inc – Integrated EC000 Processor

strobe. When the A0 bit equals zero, UDS is asserted; when the A0 bit equals one, LDS is
asserted.
The word write cycle flowchart is shown in Figure 3-5. The byte write cycle flowchart is
shown in Figure 3-6. The word and byte write cycle timing is shown in Figure 3-7.
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 D15–D0
6) ASSERT UPPER DATA STROBE (UDS)
AND LOWER DATA STROBE (LDS)
TERMINATE OUTPUT TRANSFER
1) NEGATE UDS AND LDS
2) NEGATE AS
3) REMOVE DATA FROM D15–D0
4) SET R/W TO READ
START NEXT CYCLE
SLAVE
INPUT THE DATA
1) DECODE ADDRESS
2) LATCH DATA ON D15–D0
3) ASSERT DATA TRANSFER
ACKNOWLEDGE (DTACK)
TERMINATE THE CYCLE
1) NEGATE DTACK
Figure 3-5. Word Write Cycle Flowchart
MOTOROLA
MC68306 USER'S MANUAL
3-5