SET0

SET1

VDD 1 = VDD 2

RATIO

1:8

1:2

SET1

VDD1 = VDD2

SET0

WDO

Disabling and

Enabling

watchdog

12

TPS3430

SBVS366 – JULY 2018

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Feature Description (continued)

NOTE: There is no WDI signal in this figure, WDI is always at GND.

Figure 10. Enabling and Disabling the Watchdog Timer During a WDO Reset Event

7.3.2.1.3

SET0 and SET1 During Normal Watchdog Operation

The SET0 and SET1 pins can be used to control the window watchdog ratio of the lower boundary to the upper

boundary. There are four possible modes for the watchdog (see Table 6): disabled, 1:8 ratio, 3:4 ratio, and 1:2

ratio. If SET0 = 1 and SET1 = 0, then the watchdog is disabled. When the watchdog is disabled WDO does not

assert, and the TPS3430 ignores all inputs to WDI. The SET0 and SET1 pins can be changed when the device

is operational, but cannot be changed at the same time. If these pins are changed when the device is

used to change the reset timing, then a reset event must occur before the new timing condition is latched. This

change the watchdog timing option until a reset event has occurred.

Figure 11. Changing SET0 and SET1 Pins