Datasheet

CH0-ALR Bit

EALR-CH0 Bit

D2-FAIL-ALR Bit

EALR-D2-FAIL Bit

THERM-ALR Bit

EN-ALARM Bit

ALARM

AMC7812

SBAS513E –JANUARY 2011–REVISED SEPTEMBER 2013

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ALARM pin

The ALARM pin is a global alarm indicator. ALARM is an open-drain pin, as Figure 97 illustrates; an external

pull-up resistor is required. When the pin is activated, it goes low. When the pin is inactive, it is in Hi-Z status.

The ALARM pin works as an interrupt to the host so that it may query the Status Register to determine the alarm

source. Any alarm event (including analog inputs, temperatures, diode status, and device thermal condition)

activates the pin if the alarm is not masked (the corresponding EALR bit in the Alarm Control Register = '1').

When the alarm pin is masked (EN-ALARM bit = '0'), the occurrence of the event sets the corresponding status

bit in Status Register to '1', but does not activate the ALARM pin.

Figure 97. ALARM Pin

When the ALARM-LATCH-DIS bit in the Alarm Control Register is cleared ('0'), the alarm is latched. Reading the

Status Register clears the alarm status bit. Whenever an alarm status bit is set, indicating an alarm condition, it

remains set until the event that caused it is resolved and the Status Register is read. The alarm bit can only be

cleared by reading the Status Register after the event is resolved, or by hardware reset, software reset, or

power-on reset (POR). All bits are cleared when reading the Status Register, and all bits are reasserted if the

out-of limit condition still exists after the next conversion cycle, unless otherwise noted. When the ALARM-

LATCH-DIS bit in the Alarm Control Register is set ('1'), the ALARM pin is not latched. The alarm bit clears to '0'

when the error condition subsides, regardless of whether the bit is read or not.

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