SBOS740A May 2017 – May 2019 TMP116
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 23, in alert mode the status flags can be cleared by performing an I2C read of the configuration register.
Configuring the device in alert mode also affects the behaviour of the ALERT pin. In this mode, the device asserts the ALERT pin when either the HIGH_Alert or the LOW_Alert status flag is set as shown in Figure 23. The ALERT pin can be deasserted by either performing an I2C read of the configuration register (which also clears the status flags) or by performing an SMBus alert response command (see the SMBus Alert Function section). 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 and can be used in applications where detecting if the temperature goes outside of the specified range is needed.