STTS424E02BDA3F datasheet(22/51 Pages) STMICROELECTRONICS

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Temperature sensor registers

STTS424E02

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4.2.5

Event output pin functionality

The Event outputs can be programmed to be configured as either a comparator output or as

an interrupt. This is done by enabling the Output Control bit (Bit 3) and setting the Event

mode bit (Bit 0). The output pin polarity can also be specified as active-high or active-low by

setting the Event polarity bit (Bit 1).

When the Hysteresis bits (Bits 10 and 9) are enabled, hysteresis may be used to sense

temperature movement around trigger points. For example, when using the “Above Alarm

window” bit (Temperature register Bit 14, see Table 12 on page 24) and hysteresis is set to

3°C, as the temperature rises, Bit 14 is set (Bit 14 = 1). The temperature is above the alarm

window and the Temperature register contains a value that is greater than the value set in

the Alarm Temperature Upper Boundary register (see Table 15 on page 25).

If the temperature decreases, Bit 14 will remain set until the measured temperature is less

than or equal to the value in the Alarm Temperature Upper Boundary register minus 3°C

(see Figure 8 on page 21 and Table 10 on page 21 for details.

Similarly, when using the “Below Alarm window” bit (Temperature register Bit 13, see

Table 12 on page 24) will be set to '0'. The temperature is equal to or greater than the value

set in the Alarm Temperature Lower Boundary register (see Table 16 on page 26). As the

temperature decreases, Bit 13 will be set to '1' when the value in the Temperature register is

less than the value in the Alarm Temperature Lower Boundary register minus 3°C (see

Figure 8 on page 21 and Table 10 on page 21 for details.

The device will retain the previous state when entering the Shutdown mode. If the device

enters the Shutdown mode while the EVENT pin is low, the Shutdown current will increase

due to the additional event output pull-down current.

Note:

Hysteresis is also applied to the EVENT pin functionality. When either of the Lock bits (Bits 6

and 7) are set, these bits cannot be altered.

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