Sensor: adt7420

Overview

This sample application periodically (1Hz) measures the ambient temperature in degrees Celsius. The result is written to the console.

When configured in trigger mode the update interval is 5 s, and the sample maintains a |plusminus| 1 |deg| C window around a recent temperature. As soon as the temperature goes outside the window an interrupt causes the application to display an event and update the upper and lower window boundaries.

Trigger mode is not enabled with CONFIG_ADT7420_TRIGGER directly. Instead, enable one of the ADT7420 driver trigger options:

  • CONFIG_ADT7420_TRIGGER_GLOBAL_THREAD=y to handle interrupts using the global work queue.

  • CONFIG_ADT7420_TRIGGER_OWN_THREAD=y to create a dedicated thread for ADT7420 interrupt handling.

If the measured temperature stays within the current window, log messages such as Wait for trigger...timed-out are expected until the threshold is crossed.

Requirements

  • Atmosic EVK <board | serial>

  • ADT7420 sensor connected on I2C

  • For trigger mode, connect the ADT7420 INT pin to an interrupt-capable GPIO

Building and Running

This sample is built from openair/samples/sensor/adt7420.

Standard build command:

west build -p always -b <BOARD> openair/samples/sensor/adt7420 --sysbuild -T samples.sensor.adt7420.atm

Trigger mode build commands:

west build -p always -b <BOARD> openair/samples/sensor/adt7420 --sysbuild -T samples.sensor.adt7420.atm -- -DCONFIG_ADT7420_TRIGGER_GLOBAL_THREAD=y

west build -p always -b <BOARD> openair/samples/sensor/adt7420 --sysbuild -T samples.sensor.adt7420.atm -- -DCONFIG_ADT7420_TRIGGER_OWN_THREAD=y

Trigger mode also requires the ADT7420 devicetree node to define int-gpios. The sample app.overlay does not currently include this property, so add a board-specific overlay or update the local overlay before building in trigger mode.

Example overlay addition:

&arduino_i2c {
    adt7420@4b {
        int-gpios = <&gpio1 5 GPIO_ACTIVE_HIGH>;
    };
};

Update the GPIO controller, pin number, and flags to match the board and the way the ADT7420 INT pin is wired.

Flash command:

west flash --no-rebuild --device <DEVICE_ID> --jlink --fast_load [--erase_flash]