M5Stack Fire的录音使用

vany5921

       单通道录音，使用硬件定时器与中断进行采样，通过DAC进行播放

1. #include <M5Stack.h>
   
2. #include <atomic> /* https://baptiste-wicht.com/posts/2012/07/c11-concurrency-tutorial-part-4-atomic-type.html */
   
3. 
   
4. #define MICROPHONE 34
   
5. #define SPEAKER 25
   
6. #define BACKLIGHT 32
   
7. #define BUFFER_SIZE 4*1000*1000
   
8. #define SAMPLING_FREQUENCY 48000
   
9. 
   
10. #define LOWNOISE true /* set to false to enable backlight dimming */
    
11. 
    
12. TFT_eSPI tft = TFT_eSPI();
    
13. 
    
14. // set log level to debug for output
    
15. void logMemory() {
    
16. log_d("Used PSRAM: %d from: %d", ESP.getPsramSize() - ESP.getFreePsram(), ESP.getPsramSize() );
    
17. }
    
18. 
    
19. int8_t* sampleBuffer;
    
20. uint32_t allocatedSamples;
    
21. std::atomic<std::uint32_t> currentSample{0};
    
22. static hw_timer_t * sampleTimer{NULL}; /* only one timer is (re)used for both sampling and playback */
    
23. unsigned int sampling_period_us = round( 1000000 * ( 1.0 / SAMPLING_FREQUENCY ) );
    
24. 
    
25. static void IRAM_ATTR _sampleISR() {
    
26. uint32_t pos = currentSample.load();
    
27. if ( pos > BUFFER_SIZE - 1 ) {
    
28. timerEnd( sampleTimer );
    
29. sampleTimer = NULL;
    
30. return;
    
31. }
    
32. sampleBuffer[pos] = analogRead( MICROPHONE ) >> 4;
    
33. currentSample++;
    
34. }
    
35. 
    
36. bool startSampler() {
    
37. if ( NULL != sampleTimer ) return false;
    
38. delay(170); /* to not record the click from releasing the button */
    
39. currentSample.store( 0, std::memory_order_relaxed );
    
40. sampleTimer = timerBegin( 0, 80, true );
    
41. timerAttachInterrupt( sampleTimer, &_sampleISR, true );
    
42. timerAlarmWrite( sampleTimer, sampling_period_us, true );
    
43. timerAlarmEnable( sampleTimer );
    
44. return true;
    
45. }
    
46. 
    
47. void setup() {
    
48. pinMode( MICROPHONE, INPUT );
    
49. pinMode( SPEAKER, OUTPUT );
    
50. logMemory();
    
51. 
    
52. tft.init();
    
53. tft.setRotation( 1 );
    
54. tft.fillScreen( TFT_BLACK );
    
55. tft.setTextSize( 2 );
    
56. tft.drawString( "M5-Stack voicerecorder", 10, 5, 2 );
    
57. 
    
58. if ( LOWNOISE ) {
    
59. pinMode( BACKLIGHT, OUTPUT );
    
60. digitalWrite( BACKLIGHT, HIGH ); // This gives the least noise
    
61. } else {
    
62. ledcAttachPin( BACKLIGHT, 0);
    
63. ledcSetup( 0, 1300, 16 );
    
64. ledcWrite( 0, 0xFFFF / 16 ); // Dimming the BACKLIGHT will produce more base noise
    
65. }
    
66. 
    
67. if ( !ESP.getPsramSize() ) {
    
68. tft.setCursor( 55, 40 );
    
69. tft.print( "NO PSRAM FOUND!" );
    
70. while ( 1 ) delay( 100 );
    
71. }
    
72. 
    
73. 
    
74. sampleBuffer = (int8_t*)ps_malloc( BUFFER_SIZE * sizeof( int8_t ) );
    
75. 
    
76. tft.setCursor( 15, 40 );
    
77. tft.printf( "%3.1fkHz %5.1fkB %6.2fs", SAMPLING_FREQUENCY / 1000.0, ( BUFFER_SIZE * sizeof( int8_t ) ) / 1000.0, BUFFER_SIZE / (float)SAMPLING_FREQUENCY );
    
78. tft.drawString( "REC", 45, 200, 2 );
    
79. tft.drawString( "PLAY", 130, 200, 2 );
    
80. tft.drawString( "STOP", 220, 200, 2 );
    
81. }
    
82. 
    
83. void loop() {
    
84. M5.update();
    
85. if ( !sampleTimer && M5.BtnA.pressedFor( 5 ) ) startSampler();
    
86. if ( !sampleTimer && M5.BtnB.pressedFor( 5 ) ) startPlayback();
    
87. uint32_t pos = currentSample.load();
    
88. tft.setCursor( 85, 100 );
    
89. tft.printf( "%3i%% %6.2fs", map( pos, 0, BUFFER_SIZE - 1, 0, 100 ), pos / (float)SAMPLING_FREQUENCY );
    
90. tft.setCursor( 60, 130 );
    
91. tft.printf( " %7i/%7i", pos, BUFFER_SIZE );
    
92. if ( sampleTimer && M5.BtnC.pressedFor( 2 ) ) {
    
93. timerAlarmDisable( sampleTimer );
    
94. timerEnd( sampleTimer );
    
95. sampleTimer = NULL;
    
96. dacWrite( SPEAKER, 0 );
    
97. }
    
98. delay(10);
    
99. }
    
100. 
     
101. void IRAM_ATTR _playThroughDAC_ISR() {
     
102. uint32_t pos = currentSample.load();
     
103. if ( pos > BUFFER_SIZE - 1 ) {
     
104. timerEnd( sampleTimer );
     
105. sampleTimer = NULL;
     
106. dacWrite( SPEAKER, 0 );
     
107. return;
     
108. }
     
109. dacWrite( SPEAKER, sampleBuffer[pos] );
     
110. currentSample++;
     
111. }
     
112. 
     
113. bool startPlayback() {
     
114. if ( NULL != sampleTimer ) return false;
     
115. currentSample.store( 0, std::memory_order_relaxed );
     
116. sampleTimer = timerBegin( 0, 80, true );
     
117. timerAttachInterrupt( sampleTimer, &_playThroughDAC_ISR, true );
     
118. timerAlarmWrite( sampleTimer, sampling_period_us, true );
     
119. timerAlarmEnable( sampleTimer );
     
120. return true;
     
121. }
     

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