EP4SE360F35I4 Datasheet, PDF (392/432 Pages) Altera Corporation – This section provides a complete overview of all features relating to the Stratix IV device family, which is the most architecturlly advanced

10–56
Chapter 10: Configuration, Design Security, and Remote System Upgrades in Stratix IV Devices
Remote System Upgrade Mode
1 The user watchdog timer is automatically disabled for factory configurations. For
more information about the user watchdog timer, refer to “User Watchdog Timer” on
page 10–61.
If there is an error while loading the application configuration, the cause of the
reconfiguration is written by the dedicated circuitry to the remote system upgrade
status register. Actions that cause the remote system upgrade status register to be
written are:
■ nSTATUS driven low externally
■ Internal CRC error
■ User watchdog timer time-out
■ A configuration reset (logic array nCONFIG signal or external nCONFIG pin assertion
to low)
Stratix IV devices automatically load the factory configuration located at page address
zero. This user-designed factory configuration can read the remote system upgrade
status register to determine the reason for the reconfiguration. The factory
configuration then takes appropriate error recovery steps and writes to the remote
system upgrade control register to determine the next application configuration to be
loaded.
When Stratix IV devices successfully load the application configuration, they enter
into user mode. In user mode, the soft logic (Nios II processor or state machine and
the remote communication interface) assists the Stratix IV device 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 and control register, determines the
valid application configuration to load, writes the remote system upgrade control
register accordingly, and initiates system reconfiguration.
Stratix IV Device Handbook
Volume 1
September 2012 Altera Corporation