DDS Unit

DDS is a signal source Unit. It uses the AD9833 programmable waveform generator + STM32F0 micro controller. Based on I2C communication interface (addr:0x31) It can easily control the signal source to output multiple waveforms (sine wave, triangle wave, square wave output, sawtooth wave, signal output amplitude 0-0.6V) and adjust the frequency and phase.

Support the following products:

Micropython Example:

# SPDX-FileCopyrightText: 2024 M5Stack Technology CO LTD
#
# SPDX-License-Identifier: MIT

import os, sys, io
import M5
from M5 import *
from hardware import *
from unit import DDSUnit


i2c0 = None
dds_0 = None


def setup():
    global i2c0, dds_0

    M5.begin()
    Widgets.fillScreen(0x222222)

    i2c0 = I2C(0, scl=Pin(1), sda=Pin(2), freq=100000)
    dds_0 = DDSUnit(i2c0, 0x31)
    dds_0.set_mode(dds_0.WAVE_SQUARE)
    dds_0.set_freq(0, 1000)


def loop():
    global i2c0, dds_0
    M5.update()


if __name__ == "__main__":
    try:
        setup()
        while True:
            loop()
    except (Exception, KeyboardInterrupt) as e:
        try:
            from utility import print_error_msg

            print_error_msg(e)
        except ImportError:
            print("please update to latest firmware")

UIFLOW2 Example:

cores3_dds_example.m5f2

class DDSUnit

Constructors

class DDSUnit(i2c: I2C, address: int | list | tuple = 0x31)

Initialize the DDSUnit.

参数:

i2c (I2C) – The i2c bus the unit is connected to.
address (int) – The I2C address of the DDSUnit. Default is 0x31.

UIFLOW2:

Methods

DDSUnit.set_freq(index: int = 0, freq: int = 1000) → None

Set the frequency of the DDS.

参数:

index (int) – The register number of the DDS, range from 0 to 1.
freq (int) – The frequency of the DDS in Hz.

UIFLOW2:

DDSUnit.set_phase(index: int = 0, phase: int = 0) → None

Set the phase of the DDS.

参数:

index (int) – The register number of the DDS, range from 0 to 1.
phase (int) – The phase of the DDS in degrees.

UIFLOW2:

DDSUnit.set_freq_phase(f_index: int = 0, freq: int = 1000, p_index: int = 0, phase: int = 0) → None

Set the frequency and phase of the DDS.

参数:

f_index (int) – The register number of the frequency, range from 0 to 1.
freq (int) – The frequency of the DDS in Hz.
p_index (int) – The register number of the phase, range from 0 to 1.
phase (int) – The phase of the DDS in degrees.

UIFLOW2:

DDSUnit.set_mode(mode) → None

Set the output mode of the DDS.

参数:

mode (int) –

The output mode of the DDS.

Options:

DDSUnit.WAVE_SINE: Sine
DDSUnit.WAVE_TRIANGLE: Triangle
DDSUnit.WAVE_SQUARE: Square
DDSUnit.WAVE_SAWTOOTH: Sawtooth
DDSUnit.WAVE_DC: DC

UIFLOW2:

DDSUnit.set_ctrl(f_index_sel: int = 0, p_index_sel: int = 0, disable_mclk=False, disable_dac=False, reset=False) → None

Set the control bytes of the DDS.

参数:

f_index_sel (int) – The frequency register select. range from 0 to 1.
p_index_sel (int) – The phase register select. range from 0 to 1.
disable_mclk (bool) – disable the MCLK.
disable_dac (bool) – disable the DAC.
reset (bool) – reset the DDS. If is true, other parameters will be ignored.

UIFLOW2:

DDSUnit.select_freq_reg(index: int = 0) → None

Select the frequency register of the DDS.

参数:: index (int) – The index of the frequency register. range from 0 to 1

UIFLOW2:

DDSUnit.select_phase_reg(index: int = 0) → None

Select the phase register of the DDS.

参数:: index (int) – The index of the phase register. range from 0 to 1

UIFLOW2:

DDSUnit.quick_output(mode: int = WAVE_SINE, freq: int = 1000, phase: int = 0) → None

Quickly set the output mode, frequency and phase of the DDS.

参数:

mode (int) –
The output mode of the DDS.
Options:
- DDSUnit.WAVE_SINE: Sine
- DDSUnit.WAVE_TRIANGLE: Triangle
- DDSUnit.WAVE_SQUARE: Square
- DDSUnit.WAVE_SAWTOOTH: Sawtooth
- DDSUnit.WAVE_DC: DC
freq (int) – The frequency of the DDS in Hz.
phase (int) – The phase of the DDS in degrees.

UIFLOW2:

DDSUnit.output(f_index: int = 0, p_index: int = 0) → None

Output the DDS signal.

参数:

f_index (int) – The index of the frequency register. range from 0 to 1
p_index (int) – The index of the phase register. range from 0 to 1

UIFLOW2:

DDSUnit.set_sleep_mode(mode: int = SLEEP_MODE_1) → None

Set the sleep mode of the DDS.

参数:

mode (int) –

The sleep mode of the DDS.

Options:

DDSUnit.SLEEP_MODE_NONE: None
DDSUnit.SLEEP_MODE_1: Disable MCLK
DDSUnit.SLEEP_MODE_2: Disable MCLK and DAC

UIFLOW2:

DDSUnit.reset() → None

Reset the DDS.

UIFLOW2:

Constants

DDSUnit.WAVE_SINE: Sine wave output.

DDSUnit.WAVE_TRIANGLE: Triangle wave output.

DDSUnit.WAVE_SQUARE: Square wave output.

DDSUnit.WAVE_SAWTOOTH: Sawtooth wave output.

DDSUnit.WAVE_DC: DC wave output.

DDSUnit.SLEEP_MODE_NONE: No sleep mode.

DDSUnit.SLEEP_MODE_1: Disable mclk but keep dac.

DDSUnit.SLEEP_MODE_2: Disable mclk and dac.