PM3350-SW View Datasheet(PDF) - PMC-Sierra
Part Name
Description
MFG CO.
'PM3350-SW' PDF : 224 Pages View PDF
ELAN 8X10
DATA SHEET
PMC-970109
ISSUE 3
PM3350 ELAN 8 X10
8 PORT ETHERNET SWITCH
The ELAN 8x10 expects to find executable firmware code within the boot image that will
perform the actual initialization process. However, the boot image is only 8 bits wide,
and thus the firmware code supplied within it cannot be directly executed by the ELAN
8x10 Switch Processor, which uses 32-bit instructions located on 32-bit boundaries. It is
thus necessary for the ELAN 8x10 to copy the boot image to a block of RAM that is set
aside for the purpose, and to convert the 8-bit boot image to a 32-bit version so that the
boot firmware code can be directly executed.
When a proper boot image signature is found, therefore, the ELAN 8x10 will
automatically go on to read a preformatted header within the boot image. This header
should supply information required to copy the boot image to a pre-allocated block of
RAM, and is formatted as follows:
Field
Size,
Bytes
1
3
2
3
3
4
4
Byte Offsets
from Start
+16
+20,+24,+28
+32,+36
+40,+44,+48
+52,+56,+60
+64,+68,+72,+76
+80,+84,+88,+92
Mnemonic
Description
HDRFLAGS
CPYTARGET
CPYSIZE
CPYFROM
BOOTSTART
CHECKSUM
SPACER
Boot image processing flags
Target RAM block to copy 8-bit boot
image to
Amount of data to copy in 64-byte
blocks
Source of copy data within boot image
Starting address of bootstrap firmware
in target RAM block (valid after copy
completed)
32-bit checksum, computed over entire
boot image (including checksum field)
Must be set to 0x00000000
hexadecimal
The HDRFLAGS field supplies some control bits that determine how the ELAN 8x10 will
handle the boot image, and is formatted as follows:
7
6
5
4
EightBit
CpyInt
JmpInt
0
reserved
EightBit:
If set, indicates that the boot image is formatted as an eight-bit-wide memory
block (following the general format that has already been presented);
otherwise, indicates a 32-bit boot image in a special format. This bit is
intended for factory use only, and should always be set by the customer.
CpyInt:
If this bit is set, the contents of the boot image should be copied to the
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