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MPR121 - Proximity Capacitive Touch Sensor Controller

Summary

The 12-channels I2C proximity capacitive touch sensor controller.

Device Family

MPR121: https://www.sparkfun.com/datasheets/Components/MPR121.pdf

Binding Notes

The binding provides different options of device configuration. The device can be configured to update the channel statuses periodically. Also it supports custom configuration of controller registers.

Default configuration with manually updating of channel statuses

var i2cDevice = I2cDevice.Create(new I2cConnectionSettings(busId: 1, deviceAddress: Mpr121.DefaultI2cAddress));
var mpr121 = new Mpr121(device: i2cDevice);

var statuses = mpr121.ReadChannelStatuses();
var status = statuses[Channels.Channel01]
    ? "pressed"
    : "released";

Console.WriteLine($"The 1st channel is {status}");

Channel statuses auto refresh

var i2cDevice = I2cDevice.Create(new I2cConnectionSettings(busId: 1, deviceAddress: Mpr121.DefaultI2cAddress));

// Initialize controller with default configuration and auto-refresh the channel statuses every 100 ms.
var mpr121 = new Mpr121(device: i2cDevice, periodRefresh: 100);

// Subscribe to channel statuses updates.
mpr121.ChannelStatusesChanged += (object sender, ChannelStatusesChangedEventArgs e) =>
    {
        var channelStatuses = e.ChannelStatuses;
        // do something.
    };

Custom MPR121 registers configuration

var i2cDevice = I2cDevice.Create(new I2cConnectionSettings(busId: 1, deviceAddress: Mpr121.DefaultI2cAddress));
var config = new Mpr121Configuration
{
    MaxHalfDeltaRising = 0x01,
    NoiseHalfDeltaRising = 0x01,
    NoiseCountLimitRising = 0x00,
    FilterDelayCountLimitRising = 0x00,
    MaxHalfDeltaFalling = 0x01,
    NoiseHalfDeltaFalling = 0x01,
    NoiseCountLimitFalling = 0xFF,
    FilterDelayCountLimitFalling = 0x01,
    ElectrodeTouchThreshold = 0x0F,
    ElectrodeReleaseThreshold = 0x0A,
    ChargeDischargeTimeConfiguration = 0x04,
    ElectrodeConfiguration = 0x0C
};

var mpr121 = new Mpr121(device: i2cDevice, configuration: config);
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