Avago Technologies LSI53C1030 - Manual (Page 56)

2-26 Functional Description
Version 2.2 Copyright © 2001, 2002, 2003 by LSI Logic Corporation. All rights reserved.
2.5.2 NVSRAM Interface
The LSI53C1030 Fusion-MPT firmware is capable of maintaining an
Integrated Mirroring (IM) volume of the boot drive. IM firmware requires
a 32 Kbyte NVSRAM in order to perform write journaling. Write journaling
is used to verify that the mirrored disks in the IM volume are
synchronized with each other. The NVSRAM also stores additional code
and data used for error and exception handling, and it stores IM
configuration information during serial EEPROM updates. The disk write
log uses approximately 4 Kbytes of the NVSRAM.
Figure 2.5 provides a block diagram illustrating how to connect the
NVSRAM. This design employs the CPLD to latch the address instead
of using separate address latches.
When using an NVSRAM, pull the MAD[3] Power-On Sense pin HIGH
during board boot-up. This configures the external memory interface as
an NVSRAM interface. During operation, RAMCE/ selects the NVSRAM
when MAD[3] is pulled HIGH.
Table 2.4 Flash Signature Value
Flash Address Flash Signature Values
Bytes [3:0] 0xEA XX XX XX
Bytes [7:4] 0x5A 0xEA 0xA5 0x5A
Bytes [11:8] 0xA5 0x5A 0xEA 0xA5
Bytes [15:12] 0x5A 0xA5 0x5A 0xEA