Window Mode - Infineon XMC7000 Series Using Manual

Using the Watchdog Timer in XMC7000 family MCUs
Multi-counter WDT
The UPPER_ACTION[1:0] bit field in the CONFIG register specifies how a FAULT is handled:
No action is taken
•
Generate only a FAULT to be handled by the FAULT structures
•
Generate a FAULT and trigger a RESET if this FAULT is not handled in < 3 clock cycles
•
3.5

Window mode

This mode is related to Subcounter 0 and Subcounter 1 only, and is similar to that of the basic WDT. See
2.6 Window mode. The difference is that the LOWER_LIMIT is a 16-bit value, and if the subcounter is serviced
before the counter reaches the LOWER_LIMIT value, a FAULT is generated to be handled in the FAULT
structures.
The UPPER_ACTION[5:4] and LOWER_ACTION[1:0] bit fields in the CONFIG register specify how a FAULT is
handled as follows:
No action is taken
•
Generate only a FAULT to be handled by the FAULT structures
•
Generate a FAULT and trigger a RESET if this FAULT is not handled in < 3 clk cycles
•
In Figure 9, the window mode is shown when FAULT_THEN_RESET is selected as LOWER_ACTION and
UPPER_ACTION. Four scenarios are possible while LOWER_ACTION, WARN_ACTION, and UPPER_ACTION are
activated accordingly:
Counter is serviced between LOWER_LIMIT and WARN_LIMIT: This is the regular behavior of the MCWDT. No
•
WARN interrupt is issued and no RESET is done.
Counter is serviced between WARN_LIMIT and UPPER_LIMIT: The service is done late; a WARN interrupt is
•
issued but no RESET is done.
Counter is not serviced at all: A WARN interrupt is issued but even then, the CTR0/1_SERVICE bit is not set.
•
When the counter reaches the UPPER_LIMIT, a FAULT is issued. If the firmware does not handle this FAULT
to bring the system back into a safe state, a RESET is issued after a fixed number of LFCLK cycles.
Counter is serviced before the LOWER_LIMIT is reached: The counter is serviced too early; a FAULT is issued
•
followed by a RESET in case the FAULT is not handled in time by the firmware.
UPPER_LIMIT
WARN_LIMIT
LOWER_LIMIT
Figure 9 Subcounter 0/1 operation in window mode with FAULT and RESET action
Application Note
Counts value
0xFFFF
CTR0/1_SERVICE
CTR0/1_INT
interrupt 1
CTR0/1_SERVICE FAULT
CTR0/1_SERVICE
CTR0/1_INT
Interrupt 2
16 of 33
Time
RESET
002-33887 Rev. *A
2022-05-25