File syn_dds.h¶

Direct Digital Synthesis (DDS) Waveform Synthesizer. More...

#include "../common/syn_defs.h"
#include "../util/syn_qmath.h"
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

Classes¶

Type	Name
struct	SYN_DDS DDS Generator State Instance.

Public Types¶

Type	Name
enum	SYN_DDS_Waveform DDS Waveform Types.

Public Functions¶

Type	Name
SYN_Status	syn_dds_fill_q16 (SYN_DDS * dds, q16_t * buf, size_t count) Fill a Q16.16 buffer with consecutive DDS samples.
SYN_Status	syn_dds_fill_u16 (SYN_DDS * dds, uint16_t * buf, size_t count, uint16_t dac_center, uint16_t dac_span) Fill a unsigned 16-bit integer buffer for DAC DMA output.
SYN_Status	syn_dds_init (SYN_DDS * dds, SYN_DDS_Waveform type, uint32_t freq_hz, uint32_t sample_rate_hz) Initialize a DDS Generator instance.
SYN_Status	syn_dds_set_duty (SYN_DDS * dds, float duty_pct) Set PWM duty cycle (for SYN_DDS_SQUARE mode).
SYN_Status	syn_dds_set_freq (SYN_DDS * dds, uint32_t freq_hz, uint32_t sample_rate_hz) Set the output frequency of the DDS generator.
SYN_Status	syn_dds_set_gain (SYN_DDS * dds, q16_t amplitude, q16_t offset) Set the peak amplitude and DC offset.
q16_t	syn_dds_step (SYN_DDS * dds) Compute and advance the DDS generator by one sample step.

Detailed Description¶

Implements a zero-malloc Q16.16 fixed-point DDS signal generator supporting Sine, Triangle, Sawtooth, Square/PWM, and Noise waveforms.

Public Types Documentation¶

enum SYN_DDS_Waveform¶

DDS Waveform Types.

enum SYN_DDS_Waveform {
    SYN_DDS_SINE = 0,
    SYN_DDS_TRIANGLE = 1,
    SYN_DDS_SAWTOOTH = 2,
    SYN_DDS_SQUARE = 3,
    SYN_DDS_NOISE = 4
};

Public Functions Documentation¶

function syn_dds_fill_q16¶

Fill a Q16.16 buffer with consecutive DDS samples.

SYN_Status syn_dds_fill_q16 (
    SYN_DDS * dds,
    q16_t * buf,
    size_t count
)

Parameters:

dds Pointer to DDS instance.
buf Output Q16.16 buffer.
count Number of samples to generate.

Returns:

SYN_OK on success.

function syn_dds_fill_u16¶

Fill a unsigned 16-bit integer buffer for DAC DMA output.

SYN_Status syn_dds_fill_u16 (
    SYN_DDS * dds,
    uint16_t * buf,
    size_t count,
    uint16_t dac_center,
    uint16_t dac_span
)

Parameters:

dds Pointer to DDS instance.
buf Output 16-bit DAC buffer.
count Number of samples.
dac_center Center DAC value (e.g. 2048 for 12-bit DAC).
dac_span Maximum peak-to-peak DAC range (e.g. 2047).

Returns:

SYN_OK on success.

function syn_dds_init¶

Initialize a DDS Generator instance.

SYN_Status syn_dds_init (
    SYN_DDS * dds,
    SYN_DDS_Waveform type,
    uint32_t freq_hz,
    uint32_t sample_rate_hz
)

Parameters:

dds Pointer to DDS instance.
type Waveform type.
freq_hz Target output frequency in Hz.
sample_rate_hz Sample rate in Hz.

Returns:

SYN_OK on success, or SYN_INVALID_PARAM.

function syn_dds_set_duty¶

Set PWM duty cycle (for SYN_DDS_SQUARE mode).

SYN_Status syn_dds_set_duty (
    SYN_DDS * dds,
    float duty_pct
)

Parameters:

dds Pointer to DDS instance.
duty_pct Duty cycle percentage (0.0 to 100.0%).

Returns:

SYN_OK on success.

function syn_dds_set_freq¶

Set the output frequency of the DDS generator.

SYN_Status syn_dds_set_freq (
    SYN_DDS * dds,
    uint32_t freq_hz,
    uint32_t sample_rate_hz
)

Parameters:

dds Pointer to DDS instance.
freq_hz Output frequency in Hz.
sample_rate_hz Sample rate in Hz.

Returns:

SYN_OK on success.

function syn_dds_set_gain¶

Set the peak amplitude and DC offset.

SYN_Status syn_dds_set_gain (
    SYN_DDS * dds,
    q16_t amplitude,
    q16_t offset
)

Parameters:

dds Pointer to DDS instance.
amplitude Q16.16 peak amplitude.
offset Q16.16 DC offset.

Returns:

SYN_OK on success.

function syn_dds_step¶

Compute and advance the DDS generator by one sample step.

q16_t syn_dds_step (
    SYN_DDS * dds
)

Parameters:

dds Pointer to DDS instance.

Returns:

Generated sample in Q16.16 fixed-point format.

The documentation for this class was generated from the following file src/syntropic/dsp/syn_dds.h