TMP117 datasheet(13/45 Pages) TI1

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High Limit

Low Limit

Conversion

Completed

HIGH_Alert

Status Flag

LOW_Alert

Status Flag

Configuration

2C Read

ALERT Pin

(POL = 0)

SMBus Alert

Response Command

Actual

Temperature

TMP117

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SNOSD82 – JUNE 2018

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Device Functional Modes (continued)

7.4.2.1 Alert Mode

When the T/nA bit in the configuration register is set to 0, the device is in alert mode. In this mode, the device

compares the conversion result at the end of every conversion with the values in the low limit register and high

limit register. If the temperature result exceeds the value in the high limit register, the HIGH_Alert status flag in

the configuration register is set. On the other hand, if the temperature result is lower than the value in the low

limit register, the LOW_Alert status flag in the configuration register is set. As shown in Figure 17, the user can

run an I2C read transaction on the configuration register to clear the status flags in alert mode.

When a user configures the device in alert mode, it affects the behaviour of the ALERT pin. The device asserts

the ALERT pin in this mode when either the HIGH_Alert or the LOW_Alert status flag is set, as shown in

Figure 17. The user can either run an I2C read of the configuration register (which also clears the status flags) or

run an SMBus alert response command (see the SMBus Alert Function section) to deassert the ALERT pin. The

polarity of the ALERT pin can be changed by using the POL bit setting in the configuration register.

This mode effectively makes the device behave like a window limit detector. Thus this mode can be used in

applications where detecting if the temperature goes outside of the specified range is necessary.

Figure 17. Alert Mode Timing Diagram

TMP117 Datasheet(PDF) 13 Page - Texas Instruments