MC68030FE20C Freescale Semiconductor, MC68030FE20C Datasheet - Page 184

• Manufacturer Part Number: MC68030FE20C
• Description: IC MPU 32BIT ENHANCED 132-CQFP
• Manufacturer: Freescale Semiconductor

Specifications of MC68030FE20C

• Processor Type: M680x0 32-Bit
• Speed: 20MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 132-CQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

MOTOROLA
the data strobe by itself since there is only one valid byte for every transfer.
These enable or strobe signals select only the bytes required for write cycles
or for noncachable read cycles. The other bytes are not selected, which
enable signals for 16- and 32-bit ports from the size and address encodings
and the read/write signal.
32-bit slave can only receive three bytes in the current bus cycle. A 16- or
8-bit slave can only receive one byte. The table defines the byte enables for
all port sizes. Byte data strobes can be obtained by combining the enable
signals with the data strobe signal. Devices residing on 8-bit ports can use
prevents incorrect accesses in sensitive areas such as I/O.
Figure 7-18 shows a logic diagram for one method for generating byte data
The table shows that the MC68030 transfers the number of bytes specified
misaligned or the number of bytes is greater than the port width. In these
cases, the device transfers the greatest number of bytes possible fo r the port.
For example, if the size is four bytes and the address offset (A1 :A0) is 01, a
by the size signals to or from the specified address unless the operand is
Word
3 Byte
Long Word
Byte
Transfer
Size
SlZl
0
0
0
0
0
0
0
0
1
1
1
I
I
I
1
1
T a b l e
SIZ0
I
I
I
0
0
0
0
0
0
0
0
1
1
1
1
1
B y t e , W o r d ,
7 - 7 . D a t a
MC68030 USER'S MANUAL
A1
0
I
I
0
0
0
0
0
0
0
1
1
1
1
1
1
B u s W r i t e
a n d L o n g - W o r d
A0
0
I
I
0
0
0
0
0
1
1
0
0
1
1
1
1
: B
D31 :D24
Byte (B) - Word (W) - Long-Word (L) Ports
BWL
B
BW
B
BWL
B
BW
B
BWL
B
BW
B
BWL
B
BW
E n a b l e
Data Bus Active Sections
D23:D16
S i g n a l s
P o r t s
W
WL
WL
W
W
W
WL
WL
W
W
WL
WL
W
WL
f o r
D15:D8
- -
- -
- -
- -
L
L
L
L
L
L
L
L
L
D7:D0
L
L
L
L
L
L
L
L
L
L
7-23
7