Description
These tasks collect and evaluate information from other tasks. If the information indicates the presence of a problem, they call a "bug check" mechanism. In addition, they issue the CPU's "heartbeat". If the hardware watchdog does not receive this on a timely basis, it will initiate a hard reset of the CPU's crate.
The master task receives requests for software watchdog change-of-state requests, redistributing them to each targeted slave.
Each slave task implements the software watchdog function for its CPU (e.g., interrogating registered tasks for progress). In passive mode, the slave always refreshes the hardware watchdog. In active mode, the slave only refreshes the hardware watchdog if all subsystems report progress; otherwise, it performs a "warm boot".
See also: annotated data flow animation
Role: Master
CPU(s): SIU only
Input
-
The 1553 Receive Service task sends spacecraft telecommand packets to this task.
The LCB Receive Service task sends LAT internal-protocol packets to this task.
Output
The Master task sends requests for software watchdog change-of-state requests (???) to its slave tasks.
Package(s)
Role: Slaves
CPU(s): all CPUs
Input
-
The LCB Receive Service task sends LAT internal-protocol packets to this task.
The Watchdog Master task sends requests for software watchdog change-of-state requests (???) to this task.
The Watchdog Slave tasks send status interrogation requests to this task.
Output
The task sends status interrogation requests to various slave tasks.
Package(s)