Sine wave generator

[ChrisMicro – Mon Jul 17, 2017 4:21 am] –
https://github.com/ChrisMicro/AttinySou … Modulation

I hope the OP has a clear understanding of AVR registers

Upps … that was the wrong directory. :shock:
I corrected it and hope it is more useful.

LOL

Ok.

thanks for posting

Much easier to pick one with built-in DAC.

For a rainy day, one may wish to explore Don Lancaster’s discussion on Magic Sine Waves.
https://www.tinaja.com/magsn01.shtml

In today’s world of dedicated IC’s, the discussion may hold little practical value beyond a decent review of math.

Ray

@Ray – an interesting article. Precise timing – that is why the stm32f334 has got a timer with
The STM32F3x4 product line is specifically addressing digital power conversion applications, such as D-SMPS, lighting, welding, inverters for solar systems and wireless chargers..
High-resolution timer: 217ps, self-compensated versus power supply and temperature drift..
217ps resolution available for all operating modes..
Transparent high-resolution implementation (equivalent to 4.6GHz timer)..

The sine wave generator on stm23f103 is completed.

The sine wave generator on stm23f103 is completed.

your answer provided a lot of help to others wanting to implement sine wave generation.

here is it

#define F_TIMER 72000000
#define FREQ 10000 //in Hz
#define SAMPLES ((int)sqrt(F_TIMER / FREQ))
#define T_CNT ((F_TIMER/FREQ)/SAMPLES)

#define sin_zero (T_CNT/2)
#define amp0 (sin_zero/2)
#define max_amp (sin_zero-1)

/*
#define DEBOUNCE_DELAY 100

#define DEBOUNCE_IDLE 0
#define DEBOUNCE_ACTIVE 1
*/
#include <libmaple/dma.h>

dma_tube_config dma_cfg, dma_cfg2;

int flag1 = 0;
int flag2 = 0;

int out1 = PB7;
int out2 = PA8;
int out3 = PA9;

int * val1 = new int[SAMPLES];
int * val2 = new int[SAMPLES];

int phasep = PB6;
int phasen = PB5;
int ampp = PB8;
int ampn = PB9;

int16 shift = 0;

int amp = amp0;
int cnt = 0;
int time_track = 0;
float stp = 6.2831 / SAMPLES;
int ret = 17;

timer_dev *dev1 = PIN_MAP[out1].timer_device;
timer_dev *dev2 = PIN_MAP[out2].timer_device;
uint8 cc_channel1 = PIN_MAP[out1].timer_channel;
uint8 cc_channel2 = PIN_MAP[out2].timer_channel;

void fun()
{
static uint8_t ff = 0;
flag1++;

}

void fun2()
{
static uint8_t ff = 0;
flag2++;
digitalWrite(out3, ff = (1 - ff));

}

void timer_conf()
{

timer_dma_set_base_addr(dev1, TIMER_DMA_BASE_CCR2);
timer_dma_set_burst_len(dev1, 1);
timer_dma_enable_req(dev1, cc_channel1);
timer_set_reload(dev1, T_CNT);
timer_set_prescaler(dev1, 0);

timer_dma_set_base_addr(dev2, TIMER_DMA_BASE_CCR1);
timer_dma_set_burst_len(dev2, 1);
timer_dma_enable_req(dev2, cc_channel2);
timer_set_reload(dev2, T_CNT);
timer_set_prescaler(dev2, 0);
}

void dma_conf()
{
dma_init(DMA1);
/* T4C2 DMA C4 */
dma_cfg.tube_dst = &(dev1->regs.gen->DMAR);
dma_cfg.tube_dst_size = DMA_SIZE_32BITS;
dma_cfg.tube_src = val1;
dma_cfg.tube_src_size = DMA_SIZE_32BITS;

dma_cfg.tube_nr_xfers = SAMPLES;
dma_cfg.tube_flags = DMA_CFG_SRC_INC | DMA_CFG_CIRC | DMA_CFG_CMPLT_IE;

dma_cfg.tube_req_src = DMA_REQ_SRC_TIM4_CH2;
dma_cfg.target_data = 0;

ret = dma_tube_cfg(DMA1, DMA_CH4, &dma_cfg);

/* T1C1 DMA C2 */
dma_cfg.tube_dst = &(dev2->regs.gen->DMAR);
dma_cfg.tube_dst_size = DMA_SIZE_32BITS;
dma_cfg.tube_src = val2;
dma_cfg.tube_src_size = DMA_SIZE_32BITS;

dma_cfg.tube_nr_xfers = SAMPLES;
dma_cfg.tube_flags = DMA_CFG_SRC_INC | DMA_CFG_CIRC | DMA_CFG_HALF_CMPLT_IE | DMA_CFG_CMPLT_IE;

dma_cfg.tube_req_src = DMA_REQ_SRC_TIM1_CH1;
dma_cfg.target_data = 0;

ret = dma_tube_cfg(DMA1, DMA_CH2, &dma_cfg);
}

void dma_start()
{
// dma_attach_interrupt(DMA1, DMA_CH4, fun);
dma_enable(DMA1, DMA_CH4);
timer_resume(dev1);

dma_attach_interrupt(DMA1, DMA_CH2, fun2);
dma_enable(DMA1, DMA_CH2);
timer_resume(dev2);
}

void init_wave()
{
int i;
for (i = 0; i < SAMPLES; i++)
{
val1[i] = sin_zero + amp * sin(stp * i);
val2[i] = val1[i];
}
}

void setup() {
int i;
pinMode(out1, PWM);
pinMode(out2, PWM);
pinMode(out3, OUTPUT);

Serial.begin(9600);

timer_conf();
dma_conf();
dma_start();
init_wave();

}

void loop() {

}

That looks pretty useful, what are the limitations (max frequency, sample size, etc.) and how does it work?

I was using it for 15 kHz, you change the frequency very easy – line # 2, for frequency above 2 or 3 kHz single LC filter works excellent