Chapter 9: Configuration, Design Security, and Remote System Upgrades in the Cyclone III Device Family
9–79
Remote System Upgrade
The following actions cause the remote system upgrade status register to be written:
nSTATUSdriven low externally
Internal CRC error
User watchdog timer time-out
A configuration reset (logic array nCONFIGsignal or external nCONFIGpin assertion)
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Cyclone III device family automatically load the factory configuration located at
address boot_address[23:0] = 24'b0for the AS configuration scheme, and default
address boot_address[23:0] = 24'h010000(or the updated address if the default
address is changed) for the AP configuration scheme. This user-designed factory
configuration reads the remote system upgrade status register to determine the reason
for reconfiguration. Then the factory configuration takes the appropriate error
recovery steps and writes to the remote system upgrade control register to determine
the next application configuration to be loaded.
When Cyclone III device family successfully load the application configuration, the
devices enter user mode. In user mode, the soft logic (Nios II processor or state
machine and the remote communication interface) assists the Cyclone III device
family in determining when a remote system update is arriving. When a remote
system update arrives, the soft logic receives the incoming data, writes it to the
configuration memory device, and triggers the device to load the factory
configuration. The factory configuration reads the remote system upgrade status
register, determines the valid application configuration to load, writes the remote
system upgrade control register accordingly, and starts system reconfiguration.
August 2012 Altera Corporation
Cyclone III Device Handbook
Volume 1
ALTERA [ ALTERA CORPORATION ]
