SLUSE13A January 2020 – May 2021 BQ76952
The ALERT pin is a multifunction pin that can be configured either as ALERT (to provide an interrupt to a host processor), a thermistor input, a general purpose ADC input, a general purpose digital output, or an HDQ serial communication interface. The pin can be configured as active-high, active-low, or open-drain, to accommodate different system design preferences. When configured as the HDQ interface pin, the pin will operate in open-drain mode.
When the pin is configured to drive an active high output, the output voltage is driven from either the REG18 1.8 V LDO or the REG1 LDO (which can be programmed from 1.8 V to 5.0 V). Note: if a DC or significant transient current may be driven by this pin, then the output should be configured to drive using the REG1 LDO, not the REG18 LDO.
The BQ76952 device includes functionality to generate an alarm signal at the ALERT pin, which can be used as an interrupt to a host processor. When used for the alarm function, the pin can be programmed to drive the signal as an active-low or hi-Z signal, an active-high or low signal, or an active-low or high signal (that is, inverted polarity). The alarm function within the BQ76952 device includes a programmable mask, to allow the customer to decide which of many flags or events can trigger an alarm.