149 lines
4.0 KiB
C
149 lines
4.0 KiB
C
#include <stdint.h>
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#include <string.h>
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#include "stm32f4xx_rcc.h"
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#include "stm32f4xx_gpio.h"
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#include "stm32f4xx_dac.h"
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#include "nlr.h"
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#include "misc.h"
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#include "mpconfig.h"
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#include "qstr.h"
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#include "parse.h"
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#include "obj.h"
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#include "runtime.h"
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#include "audio.h"
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#define SAMPLE_BUF_SIZE (32)
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// sample_buf_in is always the same or ahead of sample_buf_out
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// when they are the same, there are no more samples left to process
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// in this scheme, there is always 1 unusable byte in the buffer, just before sample_buf_out
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int sample_buf_in;
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int sample_buf_out;
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byte sample_buf[SAMPLE_BUF_SIZE];
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bool audio_is_full(void) {
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return ((sample_buf_in + 1) % SAMPLE_BUF_SIZE) == sample_buf_out;
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}
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void audio_fill(byte sample) {
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sample_buf[sample_buf_in] = sample;
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sample_buf_in = (sample_buf_in + 1) % SAMPLE_BUF_SIZE;
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// enable interrupt
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}
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void audio_drain(void) {
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if (sample_buf_in == sample_buf_out) {
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// buffer is empty; disable interrupt
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} else {
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// buffer has a sample; output it
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byte sample = sample_buf[sample_buf_out];
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DAC_SetChannel2Data(DAC_Align_8b_R, sample);
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sample_buf_out = (sample_buf_out + 1) % SAMPLE_BUF_SIZE;
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}
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}
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/******************************************************************************/
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// Micro Python bindings
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typedef struct _pyb_audio_t {
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mp_obj_base_t base;
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int dac_id; // 1 or 2
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} pyb_audio_t;
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// direct access to DAC
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mp_obj_t pyb_audio_dac(mp_obj_t self_in, mp_obj_t val) {
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pyb_audio_t *self = self_in;
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if (self->dac_id == 1) {
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DAC_SetChannel1Data(DAC_Align_8b_R, mp_obj_get_int(val));
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} else {
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DAC_SetChannel2Data(DAC_Align_8b_R, mp_obj_get_int(val));
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}
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return mp_const_none;
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}
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mp_obj_t pyb_audio_is_full(mp_obj_t self_in) {
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if (audio_is_full()) {
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return mp_const_true;
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} else {
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return mp_const_false;
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}
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}
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mp_obj_t pyb_audio_fill(mp_obj_t self_in, mp_obj_t val) {
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audio_fill(mp_obj_get_int(val));
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return mp_const_none;
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_audio_dac_obj, pyb_audio_dac);
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STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_audio_is_full_obj, pyb_audio_is_full);
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STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_audio_fill_obj, pyb_audio_fill);
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STATIC const mp_method_t pyb_audio_methods[] = {
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{ "dac", &pyb_audio_dac_obj },
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{ "is_full", &pyb_audio_is_full_obj },
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{ "fill", &pyb_audio_fill_obj },
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{ NULL, NULL },
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};
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STATIC const mp_obj_type_t pyb_audio_type = {
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{ &mp_type_type },
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.name = MP_QSTR_,
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.methods = pyb_audio_methods,
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};
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STATIC const pyb_audio_t pyb_audio_channel_1 = {{&pyb_audio_type}, 1};
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STATIC const pyb_audio_t pyb_audio_channel_2 = {{&pyb_audio_type}, 2};
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// create the audio object
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// currently support either DAC1 on X5 (id = 1) or DAC2 on X6 (id = 2)
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STATIC mp_obj_t pyb_Audio(mp_obj_t id) {
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// DAC peripheral clock
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RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE);
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int dac_id = mp_obj_get_int(id);
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uint pin;
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uint channel;
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mp_obj_t dac_obj;
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if (dac_id == 1) {
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pin = GPIO_Pin_4;
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channel = DAC_Channel_1;
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dac_obj = (mp_obj_t)&pyb_audio_channel_1;
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} else {
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pin = GPIO_Pin_5;
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channel = DAC_Channel_2;
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dac_obj = (mp_obj_t)&pyb_audio_channel_2;
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}
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// DAC channel configuration
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GPIO_InitTypeDef GPIO_InitStructure;
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GPIO_InitStructure.GPIO_Pin = pin;
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GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
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GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
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GPIO_Init(GPIOA, &GPIO_InitStructure);
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// DAC channel Configuration
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DAC_InitTypeDef DAC_InitStructure;
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DAC_InitStructure.DAC_Trigger = DAC_Trigger_None;
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DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;
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DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
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DAC_Init(channel, &DAC_InitStructure);
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// Enable DAC Channel
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DAC_Cmd(channel, ENABLE);
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// from now on use DAC_SetChannel[12]Data to trigger a conversion
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sample_buf_in = 0;
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sample_buf_out = 0;
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// return static object
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return dac_obj;
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}
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MP_DEFINE_CONST_FUN_OBJ_1(pyb_Audio_obj, pyb_Audio);
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