Crate variegated_fdc1004 

variegated-fdc1004

Async driver for the Texas Instruments FDC1004 Capacitance-to-Digital Converter.

The FDC1004 is a precision, 24-bit capacitance-to-digital converter that can measure capacitances from femtofarads to microfarads. It features 4 measurement channels with programmable sample rates and built-in offset compensation.

Features

• Async/await support using embedded-hal-async
• Support for all 4 measurement channels
• Configurable sample rates (100, 200, 400 SPS)
• Automatic CAPDAC offset compensation
• Single-ended and differential measurements
• Optional defmt support for logging (behind defmt feature flag)

Usage

Add this to your Cargo.toml:

[dependencies]
variegated-fdc1004 = "0.1"

# Optional: enable defmt support
variegated-fdc1004 = { version = "0.1", features = ["defmt"] }

Example

use variegated_fdc1004::{FDC1004, Channel, OutputRate, SuccessfulMeasurement};

// Create the driver with your I2C bus and delay provider  
let mut fdc = FDC1004::new(i2c_bus, 0x50, OutputRate::SPS100, delay);

// Read capacitance from channel 1 with automatic CAPDAC adjustment
let result = fdc.read_capacitance(Channel::CIN1).await?;

match result {
    SuccessfulMeasurement::MeasurementInRange(capacitance) => {
        let pf = capacitance.to_pf();
        println!("Measured capacitance: {:.2} pF", pf);
    },
    SuccessfulMeasurement::Overflow => println!("Capacitance too large"),
    SuccessfulMeasurement::Underflow => println!("Capacitance too small"),
}

Hardware Considerations

• Operating voltage: 2.7V to 5.5V
• I2C address: 0x50 (7-bit)
• Requires external 18pF reference capacitors on CAPDAC pins
• Sample rate affects both speed and accuracy

See the datasheet for complete specifications.

Interoperability

This crate can run on any async executor and is no_std compatible.

Structs

FDC1004

FDC1004 Capacitance-to-Digital Converter driver.

MeasuredCapacitance

A capacitance measurement result with associated CAPDAC offset.

Enums

Channel

FDC1004 input channel selection.

FDC1004Error

Errors that can occur when communicating with the FDC1004 chip.

Measurement

FDC1004 measurement channel identifier.

OutputRate

Output data rate configuration for FDC1004 measurements.

RegisterAddress

FDC1004 register addresses.

SuccessfulMeasurement

Result of a capacitance measurement operation.