Struct mpr121_hal::Mpr121Busless

pub struct Mpr121Busless<I2C: Write + WriteRead> { /* private fields */ }

Version of the Mpr121 driver that does not occupy the I2C bus. Instead the bus hat to be provided every time an action is done.

Safety

Assumes that the supplied I²C bus is always connected to the same mpr121. If you can’t guarantee that, consider using the owning Mpr121 version instead.

Implementations

impl<I2C: Write + WriteRead> Mpr121Busless<I2C>

pub const DEFAULT_TOUCH_THRESHOLD: u8 = 12u8

pub const DEFAULT_RELEASE_THRESOLD: u8 = 6u8

pub fn new(
    i2c: &mut I2C,
    addr: Mpr121Address,
    use_auto_config: bool
) -> Result<Self, Mpr121Error>

Creates the driver for the given I²C ports. Assumes that the I²C port is configured as master. If use_auto_config is set, the controller will use its auto configuration routine to setup charging parameters whenever it is transitioned from STOP to START mode.

Note that we use the same default values as the Adafruit implementation, except for threshold values. Use set_thresholds to define those.

pub fn new_default(i2c: &mut I2C) -> Result<Self, Mpr121Error>

Initializes the driver assuming the sensors address is the default one (0x5a). If this fails, consider searching for the driver. Or following the documentation on setting a driver address, and use new to specify the address.

Have a look at new for further documentation.

pub fn set_thresholds(&self, i2c: &mut I2C, touch: u8, release: u8)

Set the touch and release threshold for all channels. Usually the touch threshold is a little bigger than the release threshold. This creates some debounce characteristics. The correct thresholds depend on the application.

Have a look at note AN3892 of the mpr121 guidelines.

pub fn set_debounce(&self, i2c: &mut I2C, debounce_count: u8)

Sets the count for both touch and release. See 5.7 of the data sheet.

value must be 0..8, is clamped if it exceeds.

pub fn get_filtered(&self, i2c: &mut I2C, channel: u8) -> Result<u16, Mpr121Error>

Reads the filtered data form channel t. Noise gets filtered out by the chip. See 5.3 in the data sheet.

Note that the resulting value is only 10bit wide.

Note that 0 is returned, if channel > 12.

pub fn get_baseline(&self, i2c: &mut I2C, channel: u8) -> Result<u8, Mpr121Error>

Reads the baseline data for the channel. Note that this has only a resolution of 8bit.

Note that 0 is returned, if channel > 12, or reading failed

pub fn get_touched(&self, i2c: &mut I2C) -> Result<u16, Mpr121Error>

Reads the touched state of all channels. Returns a u16 where each bit 0..12 indicates whether the pin is touched or not. Use bit shifting / masking to generate a mask, or, if only one sensor’s value is needed, use get_touch_state.

Returns 0 if reading failed.

pub fn get_sensor_touch(&self, i2c: &mut I2C, channel: u8) -> bool

Returns the touch state of the given sensor.

Returns false if channel>11, or reading failed.