Crate ads1x1x

Expand description

This is a platform-agnostic Rust driver for the ADS1013, ADS1014, ADS1015, ADS1113, ADS1114, and ADS1115 ultra-small, low-power analog-to-digital converters (ADC), based on the embedded-hal traits.

This driver allows you to:

Set the operating mode to one-shot or continuous. See: into_continuous().
Make a measurement in one-shot mode. See: read().
Start continuous conversion mode. See: start().
Read the last measurement made in continuous conversion mode. See: read().
Set the data rate. See: set_data_rate().
Set the full-scale range (gain amplifier). See set_full_scale_range().
Read whether a measurement is in progress. See: is_measurement_in_progress().
Set the ALERT/RDY pin to be used as conversion-ready pin. See: use_alert_rdy_pin_as_ready().
Comparator:
- Set the low and high thresholds. See: set_high_threshold_raw().
- Set the comparator mode. See: set_comparator_mode().
- Set the comparator polarity. See: set_comparator_polarity().
- Set the comparator latching. See: set_comparator_latching().
- Set the comparator queue. See: set_comparator_queue().
- Disable the comparator. See: disable_comparator().

The devices

The devices are precision, low power, 12/16-bit analog-to-digital converters (ADC) that provide all features necessary to measure the most common sensor signals in an ultra-small package. Depending on the device, these integrate a programmable gain amplifier (PGA), voltage reference, oscillator and high-accuracy temperature sensor.

The devices can perform conversions at data rates up to 3300 samples per second (SPS). The PGA offers input ranges from ±256 mV to ±6.144 V, allowing both large and small signals to be measured with high resolution. An input multiplexer (MUX) allows to measure two differential or four single-ended inputs. The high-accuracy temperature sensor can be used for system-level temperature monitoring or cold-junction compensation for thermocouples.

The devices operate either in continuous-conversion mode, or in a single-shot mode that automatically powers down after a conversion. Single-shot mode significantly reduces current consumption during idle periods. Data is transferred through I2C.

Here is a comparison of the caracteristics of the devices:

Device	Resolution	Sample Rate	Channels	Multi-channel	Features
ADS1013	12-bit	Max 3300 SPS	1	N/A
ADS1014	12-bit	Max 3300 SPS	1	N/A	Comparator, PGA
ADS1015	12-bit	Max 3300 SPS	4	Multiplexed	Comparator, PGA
ADS1113	16-bit	Max 860 SPS	1	N/A
ADS1114	16-bit	Max 860 SPS	1	N/A	Comparator, PGA
ADS1115	16-bit	Max 860 SPS	4	Multiplexed	Comparator, PGA

Datasheets:

Usage examples (see also examples folder)

To use this driver, import this crate and an embedded_hal implementation, then instantiate the appropriate device. In the following examples an instance of the device ADS1013 will be created as an example. Other devices can be created with similar methods like: Ads1x1x::new_ads1114(...).

Create a driver instance for the ADS1013

extern crate linux_embedded_hal as hal;
extern crate ads1x1x;
use ads1x1x::{ Ads1x1x, SlaveAddr };

let dev = hal::I2cdev::new("/dev/i2c-1").unwrap();
let address = SlaveAddr::default();
let adc = Ads1x1x::new_ads1013(dev, address);
// do something...

// get the I2C device back
let dev = adc.destroy_ads1013();

Create a driver instance for the ADS1013 with an alternative address

extern crate linux_embedded_hal as hal;
extern crate ads1x1x;
use ads1x1x::{ Ads1x1x, SlaveAddr };

let dev = hal::I2cdev::new("/dev/i2c-1").unwrap();
let (a1, a0) = (true, false);
let address = SlaveAddr::Alternative(a1, a0);
let adc = Ads1x1x::new_ads1013(dev, address);

Make a one-shot measurement

extern crate embedded_hal;
use embedded_hal::adc::OneShot;
extern crate linux_embedded_hal;
#[macro_use(block)]
extern crate nb;
extern crate ads1x1x;

use linux_embedded_hal::I2cdev;
use ads1x1x::{ Ads1x1x, SlaveAddr, channel };

    let dev = I2cdev::new("/dev/i2c-1").unwrap();
    let mut adc = Ads1x1x::new_ads1013(dev, SlaveAddr::default());
    let measurement = block!(adc.read(&mut channel::DifferentialA0A1)).unwrap();
    println!("Measurement: {}", measurement);
    let _dev = adc.destroy_ads1013(); // get I2C device back

Change into continuous conversion mode and read the last measurement

extern crate linux_embedded_hal as hal;
extern crate ads1x1x;
use ads1x1x::{ Ads1x1x, SlaveAddr };

let dev = hal::I2cdev::new("/dev/i2c-1").unwrap();
let address = SlaveAddr::default();
let adc = Ads1x1x::new_ads1013(dev, address);
let mut adc = adc.into_continuous().unwrap();
adc.start().unwrap();
while(adc.is_measurement_in_progress().unwrap()) {
    // some delay...
}
let measurement = adc.read().unwrap();

Set the data rate

For 12-bit devices, the available data rates are given by DataRate12Bit. For 16-bit devices, the available data rates are given by DataRate16Bit.

extern crate linux_embedded_hal as hal;
extern crate ads1x1x;
use ads1x1x::{ Ads1x1x, SlaveAddr, DataRate16Bit };

let dev = hal::I2cdev::new("/dev/i2c-1").unwrap();
let address = SlaveAddr::default();
let mut adc = Ads1x1x::new_ads1115(dev, address);
adc.set_data_rate(DataRate16Bit::Sps860).unwrap();

Configure the comparator

Configure the comparator to assert when the voltage drops below -1.5V or goes above 1.5V in at least two consecutive conversions. Then the ALERT/RDY pin will be set high and it will be kept so until the measurement is read or an appropriate SMBus alert response is sent by the master.

extern crate linux_embedded_hal as hal;
extern crate ads1x1x;
use ads1x1x::{ Ads1x1x, SlaveAddr, ComparatorQueue, ComparatorPolarity,
               ComparatorMode, ComparatorLatching, FullScaleRange };

let dev = hal::I2cdev::new("/dev/i2c-1").unwrap();
let address = SlaveAddr::default();
let mut adc = Ads1x1x::new_ads1015(dev, address);
adc.set_comparator_queue(ComparatorQueue::Two).unwrap();
adc.set_comparator_polarity(ComparatorPolarity::ActiveHigh).unwrap();
adc.set_comparator_mode(ComparatorMode::Window).unwrap();
adc.set_full_scale_range(FullScaleRange::Within2_048V).unwrap();
adc.set_low_threshold_raw(-1500).unwrap();
adc.set_high_threshold_raw(1500).unwrap();
adc.set_comparator_latching(ComparatorLatching::Latching).unwrap();