mirror of
https://github.com/esp8266/Arduino.git
synced 2025-06-13 13:01:55 +03:00
f9110f51c2
Add optional callback after every DMA buffer interrupt for lower delay, better timing control of I2S output.
61 lines
2.5 KiB
C
61 lines
2.5 KiB
C
/*
|
|
i2s.h - Software I2S library for esp8266
|
|
|
|
Copyright (c) 2015 Hristo Gochkov. All rights reserved.
|
|
This file is part of the esp8266 core for Arduino environment.
|
|
|
|
This library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
This library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with this library; if not, write to the Free Software
|
|
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
#ifndef I2S_h
|
|
#define I2S_h
|
|
|
|
/*
|
|
How does this work? Basically, to get sound, you need to:
|
|
- Connect an I2S codec to the I2S pins on the ESP.
|
|
- Start up a thread that's going to do the sound output
|
|
- Call i2s_begin()
|
|
- Call i2s_set_rate() with the sample rate you want.
|
|
- Generate sound and call i2s_write_sample() with 32-bit samples.
|
|
The 32bit samples basically are 2 16-bit signed values (the analog values for
|
|
the left and right channel) concatenated as (Rout<<16)+Lout
|
|
|
|
i2s_write_sample will block when you're sending data too quickly, so you can just
|
|
generate and push data as fast as you can and i2s_write_sample will regulate the
|
|
speed.
|
|
*/
|
|
|
|
#ifdef __cplusplus
|
|
extern "C" {
|
|
#endif
|
|
|
|
void i2s_begin();
|
|
void i2s_end();
|
|
void i2s_set_rate(uint32_t rate);//Sample Rate in Hz (ex 44100, 48000)
|
|
void i2s_set_dividers(uint8_t div1, uint8_t div2);//Direct control over output rate
|
|
float i2s_get_real_rate();//The actual Sample Rate on output
|
|
bool i2s_write_sample(uint32_t sample);//32bit sample with channels being upper and lower 16 bits (blocking when DMA is full)
|
|
bool i2s_write_sample_nb(uint32_t sample);//same as above but does not block when DMA is full and returns false instead
|
|
bool i2s_write_lr(int16_t left, int16_t right);//combines both channels and calls i2s_write_sample with the result
|
|
bool i2s_is_full();//returns true if DMA is full and can not take more bytes (overflow)
|
|
bool i2s_is_empty();//returns true if DMA is empty (underflow)
|
|
int16_t i2s_available();// returns the number of samples than can be written before blocking
|
|
void i2s_set_callback(void (*callback) (void));
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|
|
|
|
#endif
|