CRWDT (Challenge Response Watchdog Timer)

The Challenge Response Watchdog Timer (CRWDT) uses challenge/response inter-operations during a measured window to ensure that software is in control. More...

Modules
	Macros
	Functions

Detailed Description

The Challenge Response Watchdog Timer (CRWDT) uses challenge/response inter-operations during a measured window to ensure that software is in control.

Note

Supported on PSOC4 HVMS/PA.

The functions and other declarations used in this driver are in cy_crwdt.h. You can include cy_pdl.h to get access to all functions and declarations in the PDL.

Clock Source

The CRWDT_CNT (UP COUNTER) counter is clocked by LFCLK Low-Frequency Clock

Application

The challenge and response values are provided by the Linear Feedback Shift Register (LFSR), and are used to validate time logged by CRWDT_CNT (UP COUNTER).

Firmware reads the Linear Feedback Shift Register (LFSR) value from CRWDT_CHALLENGE. The actions of reading CRWDT_CHALLENGE or writing CRWDT_RESPONSE both increment the Linear Feedback Shift Register (LFSR). The CRWDT is serviced by writing the value of CRWDT_RESPONSE in a timely manner. that value matches the current Linear Feedback Shift Register (LFSR) value.

Successful servicing resets CRWDT_CNT (UP COUNTER) to zero and a new counting period starts.

Actions

The CRWDT provides early warning and late actions using FAULTS, as well as interrupts, or forces a reset if CRWDT was not serviced for long or serviced by incorrect CRWDT_RESPONSEs.

More Information

For more information on the CRWDT peripheral, refer to the technical reference manual (TRM).

Changelog

Version	Changes	Reason for Change
1.0	Initial version