PAC1721 datasheet(24/92 Pages) MICROCHIP

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PAC1721

DS-20007088A-page 24

 2026 Microchip Technology Inc. and its subsidiaries

GPIO Triggered Single-shot Awake mode activates

when the GPIO pin is pulled and held low for longer

than 250 µs. This triggers the single-shot sample.

I2C Triggered Single-shot mode is also available. It is

used with a Refresh (any) command. Accumulator and

accumulator count operate the same as for continuous

conversion, summing every single-shot power calcula-

tion and incrementing the accumulator count. The

conversion cycle starts when the GPIO edge is sent or

when a Refresh (any) command is issued.

To enter GPIO Triggered Single-shot Awake mode from

the Sleep state, set the following bits in the CONTROL

•A0 → SAMPLE_MODE[3:0] = 1100b

•A1 → SAMPLE_MODE[3:0] = 1101b

4.10

Alert Functionality

If enabled, the Alert functionality notifies when:

• A conversion cycle completes

• The accumulator or accumulator count overflows

• An electrical parameter exceeds the set limit

• The rolling average of the most recent VBUS or

VSENSE samples changes by more than expected

Depending on the configuration, alerts trigger either the

A0 pin or the A1 pin to be pulled low and latched low.

The only exception is the Conversion Complete alert,

when a 5 µs pulse of the ALERT pin occurs. Alerts are

set at the end of conversion cycles.

4.10.1

ALERT PIN ASSIGNMENTS

Before assigning any alerts, pin A0, pin A1 or both must

be set to function as ALERT pins by programming the

CONTROL register.:

•A0 → SLOW_ALERT0[1:0] = 00b

•A1 → GPIO_ALERT1[1:0] = 00b

After configuring pin A0/A1 to function as ALERT pin,

assign alerts to the pin using the SLOW_ALERT0

For details, see Register 6-26 and Register 6-27.

When an active alert triggers, except the Conversion

Complete alert, PAC1721 sets the ANY_ALERT bit in

the SMBUS_SETTINGS register to 1b. Monitor this bit

over I2C, SMBus or on pin A0/A1 to determine if an

alert was triggered. Clearing the alert that set the bit

also clears the ANY_ALERT bit.

Note:

The SMBUS_SETTINGS register updates

without requiring a Refresh (any) command.

For more details, see Register 6-19.

4.10.2

CONVERSION COMPLETE ALERT

When the Conversion Complete (CC) alert is enabled,

the assigned ALERT pin is pulled and held low for 5 µs

after each completed conversion cycle.

To enable the Conversion Complete alert function on

the ALERT pin, follow the next steps:

Program pin A0/A1 as ALERT pin(s) in the

CONTROL register:

◦ A0 → SLOW_ALERT0[1:0] = 00b

◦ A1 → GPIO_ALERT1[1:0] = 00b

Enable the Conversion Complete alert:

ALERT_ENABLE register: ALERT_CC = 1b

Assign the alert to the A0/A1 pin:

◦ If A0 is set as ALERT pin →

SLOW_ALERT0 register: ALERT_CC0 = 1b

◦ If A1 is set as ALERT pin →

GPIO_ALERT1 register: ALERT_CC1 = 1b

Use the CC alert to read data continuously as soon as

each conversion cycle is complete. For more details,

see Register 6-26 and Register 6-27.

Note 1: Jitter caused by the low power clocking

scheme can be present when viewing the

Conversion Complete alert. This does not

impact the conversion cycle.

2: The Conversion Complete alert does not

impact the ALERT_STATUS register. For

more details, see Register 6-18.

4.10.3

ALERT FUNCTIONALITY –

VOLTAGE, CURRENT AND POWER

The Alert functionality enables the detection of voltage

and current events that equal or exceed programmable

limits, for one or more samples. To monitor alert status,

set pin A0/A1 to correspond to a single specific alert or

to multiple alerts by programming the corresponding

bits in the SLOW_ALERT0 register for pin A0 and the

GPIO_ALERT1 register for pin A1. For more details,

see Register 6-26 and Register 6-27.

Alert status can also be monitored over SMBus or I2C

by reading the ALERT_STATUS register. For more

details, see Register 6-18.

Alerts can be triggered by various events:

•VBUS overvoltage or undervoltage

•VSENSE overcurrent or undercurrent

• Fast rising or falling voltage or current

• Overpower warning or overpower critical

• Conversion cycle complete

• Accumulator or accumulator count hitting a limit for

fullness or overflow

Note:

The Slow function is disabled if the Alert

function is programmed on the same pin.

PAC1721 Datasheet(PDF) 24 Page - Microchip Technology

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