Microcontroller User's Manual

13-8 MCF5282 User’s Manual MOTOROLA
Data Transfer Operation
• In S4, the external device can stop driving data after the rising edge of CLKOUT.
However data could be driven up to S5.
• For a read cycle, the external device stops driving data between S4 and S5.
States are described in Table 13-3.
13.4.4 Write Cycle
During a write cycle, the MCF5282 sends data to the memory or to a peripheral device. The
write cycle flowchart is shown in Figure 13-7.
Figure 13-7. Write Cycle Flowchart
The write cycle timing diagram is shown in Figure 13-8.
Figure 13-8. Basic Write Bus Cycle
Table 13-3 describes the six states of a basic write cycle.
System
1. Set R/W
to write
2. Place address on A[31:0]
3. Assert TIP
and SIZ[1:0]
4. Assert TS
5. Place data on D[31:0]
6. Negate TS
1. Decode address
2. Store data on D[31:0]
3. Assert TA
1. Sample TA low
2. Stop driving data from D[31:0]
1. Negate TA
1. Start next cycle
MCF5282
R/W
TIP
TS
D[31:0]
TA
S0 S1 S2 S3 S4 S5
Write
CLKOUT
CSn, BSn
A[31:0], SIZ[1:0]