20-8
MCF5272 User’s Manual
Data Transfer Mechanism
Table 20-4 lists the bytes that should be driven on the data bus during read cycles by the
external peripheral device being accessed. The entries shown as Byte X are portions of the
requested operand that are read. The operand being read is defined by the size of the transfer
and A[1:0] for the bus cycle. Bytes labeled “X” are don’t cares and are not required during
that read cycle. Bytes labeled “–” are not valid transfers.
Word
8-bit
(not
supported
for
SDRAM)
00
0
1
1
1
01
0
1
1
1
10
0
1
1
1
11
0
1
1
1
16-bit
00
0
0
1
1
10
0
0
1
1
32-bit
00
0
0
1
1
10
1
1
0
0
Longword
8-bit
(not
supported
for
SDRAM)
00
0
1
1
1
01
0
1
1
1
10
0
1
1
1
11
0
1
1
1
16-bit
00
0
0
1
1
10
0
0
1
1
32-bit
00
0
0
0
0
Line
8-bit
(not
supported
for
SDRAM)
00
0
1
1
1
01
0
1
1
1
10
0
1
1
1
11
0
1
1
1
16-bit
00
0
0
1
1
10
0
0
1
1
32-bit
00
0
0
0
0
Table 20-3. Data Bus Byte Strobes (Continued)
Transfer Size
Port Size
A[1:0]
BS3
BS2
BS1
BS0
D[31:24]
D[23:16]
D[15:8]
D[7:0]
Содержание DigitalDNA ColdFire MCF5272
Страница 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
Страница 38: ...xxxviii MCF5272 User s Manual TABLES Table Number Title Page Number ...
Страница 58: ...1 10 MCF5272 User s Manual MCF5272 Specific Features ...
Страница 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Страница 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Страница 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Страница 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
Страница 338: ...13 44 MCF5272 User s Manual Application Examples ...
Страница 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Страница 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
Страница 482: ...20 30 MCF5272 User s Manual Reset Operation ...
Страница 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...
Страница 548: ...INDEX Index 12 MCF5272 User s Manual ...