MPC555
/
MPC556
BURST BUFFER
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
4-14
Figure 4-13 Code Decompression Process
4.3.10 Compression Environment Initialization
At power on reset (POR) or with a hard reset, the default settings will be activated
unless the configuration word inputs override these defaults. The compression mode
configuration data to be programmed is supplied by the user software in the flash.
The hard reset configuration word (described in
) has two bits
which control the code compression mode. Bit 21 enables code compression when
equal to “1” and disables code compression when equal to “0”. Bit 22 defines the ex-
ception table code as either compressed with a value of “1” or non-compressed with a
value of “0”.
4.4 Modes Of Operation
The burst buffer module can operate in the following modes:
• Normal
• Slave
• Reset
• Debug
• Standby
• Burst
The modes of operation are described in the following paragraphs.
Compressed
Memory
Instructions
De
Vocabulary
compressor
PowerPC™
Embedded
CPU
Bit-Aligned COF
Non-Compressed
Instruction Code
Address
COF Word-Aligned
Physical Address
Compressed
Instruction
Compressed Space
“Next Instruction”
Address
Code
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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