MC68020 Motorola, MC68020 Datasheet - Page 56

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

Table 5-5 lists the combinations of SIZ1, SIZ0, A1, and A0 and the corresponding pattern
of the data transfer for write cycles from the internal multiplexer of the MC68020/EC020 to
the external data bus.
MOTOROLA
*
x = Don't care
NOTE: The OP tables on the external data bus refer to a particular byte of the operand that
is written on that section of the data bus.
Table 5-5. MC68020/EC020 Internal to External Data Bus
Due to the current implementation, this byte is output but never used.
Byte
Word
3 Bytes
Long Word
Transfer
Size
SIZ1
0
0
0
0
0
1
1
1
1
1
1
Size
SIZ0
Multiplexer—Write Cycles
1
1
1
1
1
0
0
0
0
0
0
M68020 USER’S MANUAL
A1
Address
0
0
1
1
0
0
1
1
x
x
x
A0
0
1
0
1
0
1
0
1
0
1
x
D31–D24
OP3
OP2
OP2
OP1
OP1
OP1
OP1
OP0
OP0
OP0
OP0
External Data Bus
D23–D16
OP3
OP3
OP2
OP2
OP1
OP2
OP1
OP1
OP0
OP1
OP0
Connection
D15–D8
OP2
OP1
OP3
OP2
OP3
OP3
OP2
OP1
OP2
OP1
OP0
*
*
D7–D0
OP0
OP3
OP3
OP2
OP3
OP2
OP1
OP3
OP2
OP1
OP0
*
5- 9