MC68020 Motorola, MC68020 Datasheet - Page 59

• Manufacturer Part Number: MC68020
• Description: (MC68020 / MC68EC020) MICROPROCESSORS USERS MANUAL
• Manufacturer: Motorola

Figure 5-7 shows a word write to an 8-bit bus port. Like the preceding example, this
example requires two bus cycles. Each bus cycle transfers a single byte. SIZ1 and SIZ0
for the first cycle specify two bytes; for the second cycle, one byte. Figure 5-8 shows the
associated bus transfer signal timing.
5-12
Figure 5-7. Word Operand Write to Byte Port Example
15
D31 DATA BUS D24
BYTE MEMORY
OP2
OP2
OP3
WORD OPERAND
M68020 USER’S MANUAL
SIZ1 SIZ0 A1
1
0
MC68020/EC020
OP3
0
1
0
0
0
A0
0
1
MEMORY CONTROL
DSACK1
H
H
DSACK0
L
L
MOTOROLA