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8. BIOS Support for Program Cloning
The BIOS supports copying designated portions of flash memory from one controller (the master) to
another (the clone). The Rabbit Cloning Board connects to the programming port of the master and to the
programming port of the clone. This simple circuit can easily be incorporated into test fixtures for fast production.
Figure 8-1 Cloning Board
J1
Connect
to Master’s
J2
RXA
RXA
GND
GND
CLKA
CLKA
Vcc
/RESET
Programming
TXA
Port
N/C
Vcc
/RESET
RESET MASTER
TXA
N/C
STATUS
SMODE0
SMODE1
Connect
to Clone’s
Programming
Port
STATUS
CLONE STATUS
470 W
SMODE0
SMODE1
8.1 Overview of Cloning
If the cloning board is connected to the master, the signal CLKA is held low. This is detected in the BIOS
after the reset ends, invoking the cloning support of the BIOS. If cloning has been enabled in the master’s
BIOS, it will cold boot the target system by resetting it and downloading a primary boot program. The
master then sends the entire user program along with other user selected portions of flash memory to the
clone, where the boot program receives it and stores it in RAM then copies it to flash. Optionally, the
cloned program can begin running on the slave.
For more details on cloning, see Technical Note 207 “Rabbit Cloning Board,” available at: rabbit.com.
Rabbit 4000 Designer’s Handbook
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