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Generate Low-Power Sensor Project

Last modified by Microchip on 2023/11/10 11:18
Contents

Objective

The following step-by-step guide shows you how to create a low-power sensor project and configure low-power parameters in Atmel START. This project is generated using the ATtiny3217 Xplained Pro along with the QT7 Xplained Pro Extension Kit.

Low-power with event systemThe CPU is put into Standby mode and a periodic RTC/Timer event triggers a touch sensor measurement on the configured low power sensor. In this mode, only a single button or lump sensor (a single group of buttons/sliders/wheels) can be configured as a low-power wake-up sensor. This is also called an Event-Driven Low-Power mode.
Low-power without event systemA periodic RTC/Timer interrupt wakes up the CPU from Standby mode to trigger a touch measurement on the configured low-power sensor. In this mode, a combination of buttons/lump sensors/slider or wheel sensors can be configured as low-power wake-up sensors. This is also called Software-Driven Low-Power mode.
LumpA lump is a group of two or more buttons or slider or wheel in any combination. In addition, a lump can be configured as low-power with or without an event system.

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Reference Materials

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Procedure

Creating a Low Power Sensor

QT7 Configuration

Add the QT7 sensor configuration (i.e., two buttons, one slider) to the QTouch® device canvas page.

Refer to the "Generate User Board Touch Project" page for more details on how to create an Atmel START Project.

Screenshot of QTouch Configurator with two buttons and one slider added per QT7 design

Event-Driven Low-Power

Selecting Low-Power Sensor

Click on the desired sensor to be selected as the low-power sensor and click Configure as low power.

Configure as low power is also visible if you right-click on sensor.

Screenshot of QT7 configuration with button 0 selected and 'Configure as Low Power' button highlighted

After configuring the button as a low-power sensor, the button turns green.

Screenshot of QT7 configuration with button 0 shaded green to show it is low power

If a button is configured as a low-power sensor using the steps above, it is configured as Event-Driven Low-Power mode. If a slider or wheel is configured as low-power, then Software-Driven Low-Power mode is configured.

Configuring Lump as Low-Power

Select the three sensors and click Create Lump. The lump sensor will be displayed at the bottom of the page.

Screenshot of QT7 configuration with all sensors selected to make a lump sensor

Click on Lump sensor and click Configure as low power to configure this lump as a low-power.

By hovering the mouse over the lump, all the lumped sensors will be highlighted in yellow.

Screenshot of QT7 configuration with Lump 0 selected to 'Configure as Low Power'

The configuration parameters below are based on Event-Driven Low-Power mode.

Screenshot of Parameters/Low Power tab with 'Configure Event System' checked

The "Configuring all unused pins as output low" checkbox is optional and only to be selected after configuring all PTC, UART lines, etc.

  1. The sensor saturation must be taken care of while handling the lumps.
  2. The lump sensor threshold should be the same as the low-power detect threshold.

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Software-Driven Mode

Selecting Low-Power Sensor

Click on the desired sensor to be selected as low-power and click Configure as low power.

Configure as low power is also visible if you right-click on sensor.

Screenshot of QT7 configuration with button 0 selected and 'Configure as Low Power' button highlighted

After configuring the button as a low-power sensor, the button turns green.

Screenshot of QT7 configuration with button 0 shaded green to show it is low power

Enable Software-Driven Mode

Navigate to QTouch > Parameters > Low Power and uncheck the Configure event system checkbox to enable the Software-Driven mode.

Screenshot of Parameters/Low Power tab with 'Configure Event System' unchecked

Multiple buttons or sliders or wheels can be configured as low-power in this mode.

Select Sensors

Select two buttons and a slider and click Configure as low power.

Screenshot of QT7 configuration with all sensors selected to make Low Power

This indicates all the sensors now act as Low-Power Software-Driven sensors.

Screenshot of QT7 configuration with all sensors shaded green to show they are low power

Switching back to Event-Driven Mode from Software-Driven Mode

Enable the Configure event system checkbox.

Select any one of the sensors in the Sensor Selection dialog drop-down box to configure as an Event-Driven Low-power sensor.

Screenshot of Parameters/Low Power page with 'Enable Event System' checked and the Sensor Selection dialog box open

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