Quick Test - NXP Semiconductors freescale KV4 Series Reference Manual

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this end, two tests are implemented for the watchdog, as described in

Test. A control bit is provided to put the watchdog into functional test mode. There

is also an overriding test-disable control bit which allows the functional test mode to be

disabled permanently. After it is set, this test-disable bit can only be cleared by a reset.

These two tests achieve the overall aim of testing the counter functioning and the

compare and reset logic.

Do not enable the watchdog interrupt during these tests. If

required, you must ensure that the effective time-out value is

greater than WCT time. See

more details.

To run a particular test:

1. Select either quick test or byte test..

2. Set a certain test mode bit to put the watchdog in the functional test mode. Setting

this bit automatically switches the watchdog timer to a fast clock source. The

switching of the clock source is done to achieve a faster time-out and hence a faster

In a successful test, the timer times out after reaching the programmed time-out value and

generates a system reset.

After emerging from a reset due to a watchdog test, unlock and

configure the watchdog. The refresh and unlock operations and

interrupt are not automatically disabled in the test mode.

25.5.1 Quick test

In this test, the time-out value of watchdog timer is programmed to a very low value to

achieve quick time-out. The only difference between the quick test and the normal mode

of the watchdog is that TESTWDOG is set for the quick test. This allows for a faster test

of the watchdog reset mechanism.

Freescale Semiconductor, Inc.

Generated Resets and Interrupts

KV4x Reference Manual, Rev. 2, 02/2015

Chapter 25 Watchdog Timer (WDOG)