User`s manual

Rabbit 4000 Designer’s Handbook rabbit.com 71
8.3 Cloning Questions
The following subsections answer questions about different aspects of cloning.
8.3.1 MAC Address
Some Ethernet-enabled boards do not have the EEPROM with the MAC address. These boards can still be
used as a clone because the MAC address is in the system ID block and this structure is shipped on the
board and is not overwritten by cloning unless CL_INCLUDE_ID_BLOCKS is set to one.
If you have a custom-designed board that does not have the EEPROM or the system ID block, you may
download a program at:
http://www.rabbit.com/support/feature_downloads.html
to write the system ID block (which contains the MAC address) to your board.
To purchase a MAC address go to:
http://standards.ieee.org/regauth/oui/index.shtml
8.3.2 Different Flash Types
Since the BIOS supports a variety of flash types, the flash EPROM on the two controllers do not have to be
identical. Cloning works between master and clone controllers that have different-type flash chips because
the master copies its own universal flash driver to the clone. The flash driver determines the particulars of
the flash chip that it is driving.
8.3.3 Different Memory Sizes
It is recommended that the cloning master and slave both have the same RAM and flash sizes.
8.3.4 Design Restrictions
Digital I/O line PB1 should not be used in the design if cloning is to be used.