MC68MH360EM33L Freescale Semiconductor, MC68MH360EM33L Datasheet - Page 87

• Manufacturer Part Number: MC68MH360EM33L
• Description: IC MPU QUICC ETHER 33MHZ 240FQFP
• Manufacturer: Freescale Semiconductor

Specifications of MC68MH360EM33L

• Processor Type: M683xx 32-Bit
• Speed: 33MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 240-FQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Features: -

Figure 4-6 shows a word transfer to an 8-bit bus port. Like the preceding example, this
example requires two bus cycles. Each bus cycle transfers a single byte. The size signals
for the first cycle specify two bytes; for the second cycle, they specify one byte. Figure 4-7
shows the associated bus transfer signal timing.
4.2.2 Misaligned Operands
Since operands may reside at any byte boundaries, they may be misaligned. A byte operand
is properly aligned at any address; a word operand is misaligned at an odd address; a long
word is misaligned at an address that is not evenly divisible by four. The MC68302,
MC68000/MC68008, MC68010, and MC68340 implementations allow long-word transfers
on odd-word boundaries but force exceptions if word or long-word operand transfers are
attempted at odd-byte addresses. Although the QUICC does not enforce any alignment
restrictions for data operands (including PC relative data addresses), some performance
degradation occurs when additional bus cycles are required for long-word or word operands
MOTOROLA
Figure 4-5. Long-Word Operand Write Timing (16-Bit Data Port)
FC3–FC0
D23–D16
D31–D24
DSACK0
DSACK1
A31–A2
CLKO1
SIZ0
SIZ1
R/W
AS
DS
A0
A1
Freescale Semiconductor, Inc.
For More Information On This Product,
S0
MC68360 USER’S MANUAL
Go to: www.freescale.com
WORD WRITE
S2
LONG-WORD OPERAND WRITE TO 16-BIT PORT
0P0
0P1
S4
S0
WORD WRITE
S2
0P3
0P2
S4
Bus Operation
4-11