SYS_CLK is the main clock in the
system. This clock is needed for the proper functioning of DCC, CPU, Interconnect as
well as the ESM (Error Signaling module). If this clock freezes, then everything in
the chip stops working, including the CPU.
The recommended way to monitor this scenario is to do the following:
- Configure the ESM in PWM mode so that ERROR pin can continuously toggle when
in normal mode. See Error Signaling Module (ESM) chapter for more details on
this.
- Implement a Toggle monitor in the external PMIC or a safety monitor.
- Whenever ESM detects an internal ERROR, this signal stops toggling.
- When the SYS_CLK fails, the ESM stops receiving a clock and this too has the
effect of stopping ERROR pin toggle. Hence, the external safety monitor can
take appropriate action in this scenario.