Intel® Arria® 10 Core Fabric and General Purpose I/Os Handbook

ID 683461
Date 1/21/2022
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7.4.7. User Watchdog Timer

The user watchdog timer prevents a faulty application configuration from stalling the device indefinitely. You can use the timer to detect functional errors when an application configuration is successfully loaded into the device. The timer is automatically disabled in the factory configuration; enabled in the application configuration.

Note: If you do not want this feature in the application configuration, you need to turn off this feature by setting the Wd_en bit to 1'b0 in the update register during factory configuration user mode operation. You cannot disable this feature in the application configuration.

The counter is 29 bits wide and has a maximum count value of 229 . When specifying the user watchdog timer value, specify only the most significant 12 bits. The granularity of the timer setting is 217 cycles. The cycle time is based on the frequency of the user watchdog timer internal oscillator.

The timer begins counting as soon as the application configuration enters user mode. When the timer expires, the remote system upgrade circuitry generates a time-out signal, updates the status register, and triggers the loading of the factory configuration image. To reset the time, assert RU_nRSTIMER .