EKF SC9-TOCCATA, Руководство пользователя

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SC9-TOCCATA • CompactPCI® Serial CPU Board • 11th Generation Intel® Processors
Watchdog
An important reliability feature is a software programmable watchdog function. The
SC9-TOCCATA contains two of these watchdogs. One is part of the PCH and also known as TCO
watchdog. For a detailed description please refer to the 'Intel® 500 Series Chipset Family Platform
Controller Hub' documentation. Operating systems e.g. Linux offer a driver interface to the TCO
watchdog.
The behaviour of the 2
nd
watchdog is defined within a PLD of the SC9-TOCCATA, which
activates/deactivates the watchdog and controls its time-out period. The time-out delay is
adjustable in the steps 2, 10, 50 and 255 seconds. After programming the time-out value and
arming the WD, the related software (e.g. application program) must trigger the watchdog
periodically. For details on programming the watchdog see section 'Technical Reference - Board
Control and Status Register (BCSR)' in this manual.
This watchdog is in a passive state after a system reset. There is no need to trigger it at boot time.
The watchdog is activated on the first trigger request. If the duration between two trigger
requests exceeds the programmed period, the watchdog times out and a full system reset will be
generated. The watchdog remains in the active state until the next system reset. There is no way
to disable it once it has been put on alert, whereas it is possible to reprogram its time-out value at
any time.
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