100 lines
2.9 KiB
C
100 lines
2.9 KiB
C
#include <stdint.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 "parse.h"
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#include "compile.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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// direct access to DAC
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mp_obj_t pyb_audio_dac(mp_obj_t val) {
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DAC_SetChannel2Data(DAC_Align_8b_R, mp_obj_get_int(val));
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return mp_const_none;
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}
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mp_obj_t pyb_audio_is_full(void) {
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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 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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void audio_init(void) {
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// DAC peripheral clock
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RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE);
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// DAC channel 2 (DAC_OUT2 = PA.5) configuration
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GPIO_InitTypeDef GPIO_InitStructure;
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GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;
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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 channel2 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(DAC_Channel_2, &DAC_InitStructure);
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// Enable DAC Channel2
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DAC_Cmd(DAC_Channel_2, ENABLE);
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// from now on use DAC_SetChannel2Data to trigger a conversion
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sample_buf_in = 0;
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sample_buf_out = 0;
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// enable interrupt
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// Python interface
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mp_obj_t m = mp_obj_new_module(qstr_from_str_static("audio"));
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rt_store_attr(m, qstr_from_str_static("dac"), rt_make_function_1(pyb_audio_dac));
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rt_store_attr(m, qstr_from_str_static("is_full"), rt_make_function_0(pyb_audio_is_full));
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rt_store_attr(m, qstr_from_str_static("fill"), rt_make_function_1(pyb_audio_fill));
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rt_store_name(qstr_from_str_static("audio"), m);
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}
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