9–78
Chapter 9: Configuration, Design Security, and Remote System Upgrades in the Cyclone III Device Family
Remote System Upgrade
The factory configuration image is user designed and contains soft logic (Nios II
processor or state machine and the remote communication interface) to:
■
■
■
Process any errors based on status information from the dedicated remote system
upgrade circuitry
Communicate with the remote host and receive new application configurations
and store the new configuration data in the local non-volatile memory device
Determine which application configuration is to be loaded into the Cyclone III
device family
■
■
Enable or disable the user watchdog timer and load its time-out value (optional)
Instruct the dedicated remote system upgrade circuitry to start a reconfiguration
cycle
Figure 9–34 shows the transitions between the factory and application configurations
in remote update mode.
Figure 9–34. Transitions Between Configurations in Remote Update Mode
Configuration Error
Application 1
Configuration
Power Up
Set Control Register
and Reconfigure
Factory
Reload a Different Application
Configuration
Configuration
Error
Reload a Different Application
Application n
Configuration
Set Control Register
and Reconfigure
Configuration Error
After power up or a configuration error, the factory configuration logic writes the
remote system upgrade control register to specify the address of the application
configuration to be loaded. The factory configuration also specifies whether or not to
enable the user watchdog timer for the application configuration and, if enabled,
specifies the timer setting.
1
Only valid application configurations designed for remote update mode include the
logic to reset the timer in user mode. For more information about the user watchdog
timer, refer to “User Watchdog Timer” on page 9–85.
If there is an error while loading the application configuration, the remote system
upgrade status register is written by the dedicated remote system upgrade circuitry of
the Cyclone III device family, specifying the cause of the reconfiguration.
Cyclone III Device Handbook
Volume 1
August 2012 Altera Corporation
ALTERA [ ALTERA CORPORATION ]
