Crate ad983x

Source
Expand description

This is a platform agnostic Rust driver for the AD9833, AD9834, AD9837 and AD9838 low-power programmable waveform generators / direct digital synthesizers (DDS) using the embedded-hal traits.

This driver allows you to:

Introductory blog post

§The devices

The AD9833, AD9834, AD9837 and AD9838 are low power, programmable waveform generators capable of producing sine, triangular, and square wave outputs. Waveform generation is required in various types of sensing, actuation, and time domain reflectometry (TDR) applications. The output frequency and phase are software programmable, allowing easy tuning. No external components are needed. The frequency registers are 28 bits wide: with a 25 MHz clock rate, resolution of 0.1 Hz can be achieved; with a 1 MHz clock rate, the AD9833 can be tuned to 0.004 Hz resolution.

The devices are written to via a 3-wire serial interface (SPI). This serial interface operates at clock rates up to 40 MHz and is compatible with DSP and microcontroller standards. The devices operate with a power supply from 2.3 V to 5.5 V.

Datasheets:

Application Note:

Article explaining DDS using an AD9833:

§SysfsPin / Software control source on AD9834/AD9838

AD9834/AD9838 devices offer the possibility to control several functions either through hardware pins or software settings. While hardware pin control is selected, these software operations will be ignored by the hardware. This driver allows this as well as it would be a valid use case to configure the status of these functions while on hardware pin control mode in preparation for a smooth switch to software control.

§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 AD9833 will be created as an example. Other devices can be created with similar methods like: Ad983x::new_ad9837(...).

Please find additional examples using hardware in this repository: driver-examples.

This includes an example MIDI player that plays Beethoven’s ninth symphony.

§Set the frequency register 0 and enable

use ad983x::{Ad983x, FrequencyRegister};
use embedded_hal_bus::spi::ExclusiveDevice;
use linux_embedded_hal::{Delay, SpidevBus, SysfsPin};

let spi = SpidevBus::open("/dev/spidev0.0").unwrap();
let chip_select = SysfsPin::new(25);
let dev = ExclusiveDevice::new(spi, chip_select, Delay);
let mut dds = Ad983x::new_ad9833(dev);
dds.reset().unwrap(); // reset is necessary before operation
dds.set_frequency(FrequencyRegister::F0, 4724).unwrap();
dds.enable().unwrap();
// Given a 25 MHz clock, this now outputs a sine wave
// with a frequency of 440 Hz, which is a standard
// A4 tone.

// Get device back
let _dev = dds.destroy();

§Set frequency registers 0 and 1 and alternate between them

With a 25 MHz clock this alternates between A4 and D5 tones.

use ad983x::{Ad983x, FrequencyRegister};
use embedded_hal_bus::spi::ExclusiveDevice;
use linux_embedded_hal::{Delay, SpidevBus, SysfsPin};

let spi = SpidevBus::open("/dev/spidev0.0").unwrap();
let chip_select = SysfsPin::new(25);
let dev = ExclusiveDevice::new(spi, chip_select, Delay);
let mut dds = Ad983x::new_ad9833(dev);
dds.reset().unwrap(); // reset is necessary before operation
// A4 tone for a 25 MHz clock
dds.set_frequency(FrequencyRegister::F0, 4724).unwrap();
// D5 tone for a 25 MHz clock
dds.set_frequency(FrequencyRegister::F1, 6306).unwrap();
dds.enable().unwrap();
loop {
    // some delay
    dds.select_frequency(FrequencyRegister::F1).unwrap();
    // some delay
    dds.select_frequency(FrequencyRegister::F0).unwrap();
}

§Set the phase register 1 and select it

use ad983x::{Ad983x, PhaseRegister};
use embedded_hal_bus::spi::ExclusiveDevice;
use linux_embedded_hal::{Delay, SpidevBus, SysfsPin};

let spi = SpidevBus::open("/dev/spidev0.0").unwrap();
let chip_select = SysfsPin::new(25);
let dev = ExclusiveDevice::new(spi, chip_select, Delay);
let mut dds = Ad983x::new_ad9833(dev);
dds.reset().unwrap(); // reset is necessary before operation
dds.set_phase(PhaseRegister::P1, 4724).unwrap();
dds.select_phase(PhaseRegister::P1).unwrap();

§Set output waveform to be triangular

use ad983x::{Ad983x, OutputWaveform};
use embedded_hal_bus::spi::ExclusiveDevice;
use linux_embedded_hal::{Delay, SpidevBus, SysfsPin};

let spi = SpidevBus::open("/dev/spidev0.0").unwrap();
let chip_select = SysfsPin::new(25);
let dev = ExclusiveDevice::new(spi, chip_select, Delay);
let mut dds = Ad983x::new_ad9833(dev);
dds.reset().unwrap(); // reset is necessary before operation
dds.set_output_waveform(OutputWaveform::Triangle).unwrap();

§Power down the DAC

use ad983x::{Ad983x, PoweredDown};
use embedded_hal_bus::spi::ExclusiveDevice;
use linux_embedded_hal::{Delay, SpidevBus, SysfsPin};

let spi = SpidevBus::open("/dev/spidev0.0").unwrap();
let chip_select = SysfsPin::new(25);
let dev = ExclusiveDevice::new(spi, chip_select, Delay);
let mut dds = Ad983x::new_ad9833(dev);
dds.reset().unwrap(); // reset is necessary before operation
dds.set_powered_down(PoweredDown::Dac).unwrap();

§Use hardware pins as control source

use ad983x::{Ad983x, ControlSource};
use embedded_hal_bus::spi::ExclusiveDevice;
use linux_embedded_hal::{Delay, SpidevBus, SysfsPin};

let spi = SpidevBus::open("/dev/spidev0.0").unwrap();
let chip_select = SysfsPin::new(25);
let dev = ExclusiveDevice::new(spi, chip_select, Delay);
let mut dds = Ad983x::new_ad9838(dev);
dds.reset().unwrap(); // reset is necessary before operation
dds.set_control_source(ControlSource::HardwarePins).unwrap();
// Hardware pins can now be used to control the device.
// The corresponding software settings will be ignored.

Structs§

Ad983x
AD983x direct digital synthesizer

Enums§

ControlSource
Hardware pin / software control source for the functions: frequency register selection, phase register selection, reset of internal registers, and DAC power-down. (Only available on AD9834 and AD9838 devices)
Error
All possible errors in this crate
FrequencyRegister
Frequency registers
OutputWaveform
Output waveform
PhaseRegister
Phase registers
PoweredDown
Powered-down device configuration
SignBitOutput
Sign bit output on AD9834/AD9838 devices

Constants§

MODE
SPI mode (CPOL = 1, CPHA = 0)