202duino で 減衰鋸歯状波の音楽再生 [Arduino]
実は、波形をつくって再生するスケッチを作ってみたものの、波形によってノイズが多く、ATtiny212/412のDAC使用だと目立たなくなりました。
でも、とりあえずATtiny202での再生が第一。
ノイズが目立たないのは、矩形波（作成済）と鋸歯状波形だったので、鋸歯状波形専用のスケッチをつくりました。
なんとなく8ビットゲーム音楽っぽい仕上がりです。
でも、とりあえずATtiny202での再生が第一。
ノイズが目立たないのは、矩形波（作成済）と鋸歯状波形だったので、鋸歯状波形専用のスケッチをつくりました。
なんとなく8ビットゲーム音楽っぽい仕上がりです。
// megaTinyCore ATtiny202/212/402/412 Score Replay Sketch (positive ramp sawtooth)
#include "notes2.h" // Definition data of notes ( pitch (scale & octave), and note value (length))
#define MAX_TRACK (4) // Maximum number of tracks
// 256 times the virtual Wave Form subscript to advance in one cycle @ basic 12-note scale (from C9 to B9) (@20MHz, with an interrupt every 256clocks)
static const uint16_t OCTAVE9[] = { 7023, 7441, 7883, 8352, 8848, 9375, 9932, 10523,11148,11811,12513,13258 };
static const uint16_t Jesus[] = { // J.S.Bach "Jesu, Joy of Man's Desiring"
125 , 0 ,
b4e , g4e , a4e , b4e , d5e , c5e , c5e , e5e , d5e , d5e , g5e , F5e , g5e , d5e , b4e , g4e , a4e , b4e ,
e4e , d5e , c5e , b4e , a4e , g4e , d4e , g4e , F4e , g4e , b4e , d5e , g5hd, 0 ,
d4q , F4e , g4q , F4e , g4q , a4e , b4q , a4e , b4q , g4e , e4q , g4e ,
a4q , F4e , g4q , e4e , a3q , c4e , b3w , 0 ,
g3qd , e3qd , c3qd , b2qd , e3qd , d3qd ,
c3qd , C3qd , d3qd , g2w , 0 , 0 };
void setup(){ // Register Settings
TCB0.CTRLA = TCB_CLKSEL_CLKDIV1_gc | TCB_ENABLE_bm; // 20MHz / 1 / 256 -> 78,125Hz
TCB0.CTRLB = TCB_CNTMODE_PWM8_gc | TCB_CCMPEN_bm; // 8-Bit PWM mode, Output Enable (WO,PA6,megaTinyCore:P0)
TCB0.CCMPL = 0xff; // top value = 255
TCB0.CCMPH = 0; // output value
}
void loop(){
play202saw( Jesus ); // Playback
}
void play202saw( const uint16_t *d ){ // ATtiny202(20MHz) sawtooth(positive ramp) version
uint8_t Tracks; // Number of tracks
const uint16_t *NoteP[MAX_TRACK]; // Pointer for each track of the score
uint16_t NoteCycle, n; // Number of interrupt cycles required for the length of the reference note (96th note) and its counter (n)
uint16_t note; // Note (pitch + note value) information read from PROGMEM
uint8_t len[MAX_TRACK]; // Length of note (how many 96th notes) (subtraction counter)
uint16_t cyc[MAX_TRACK], c[MAX_TRACK];// 256 times the virtual Wave Table subscript to advance in one cycle (cyc) and its counter (c)
uint16_t env[MAX_TRACK]; // Sound amplitude (envelope)
uint8_t lap = 30; // Sound transitional cycles(laptime) (for Attenuation calculator)
// *** Preparing Scores ***
NoteCycle = F_CPU / 256 *4*60 / *d++ / MIN_NOTE; // Number of cycles required for reference note
for( Tracks = 0; Tracks < MAX_TRACK; ) { // Get the number of tracks and the start position of each track from the song data
if( *d++ != 0 ) continue; // Skip until the break comes
if( *d == 0 ) break; // If two zeros follow, end of data
len[ Tracks ] = 1; // Initialize the note length subtraction counter to the remaining 1
NoteP[ Tracks++ ] = d; // Get location in memory, Count up the number of tracks
}
n = Tracks; // Initialize the score processing so that it can be performed immediately after the start of the do loop
// *** Playback ***
do {
// * Processing Scores *
if( --n < Tracks ) { // Processing of score for each reference note length
if( !--len[n] ) {
note = *NoteP[n]++;
len[n] = (uint8_t) note; // The lower 8 bits are the length of the note (how many times the length of a 96th note)
if( note & 0xff00 ) { // If not a rest... (Leave a lingering sound even with rests)
cyc[n] = OCTAVE9[ (note>>8) & 0x0f ] >> (9 - (note>>12)); // 256 times the Wave Table subscript to advance in one cycle
c[n] = 0; // Initializes a counter for the number of cycles to create one waveform cycle
env[n] = 0xffff; // Initially, the maximum amplitude
}
}
if( !n ) n = NoteCycle;
}
// * Waveform Processing / Output *
switch( Tracks ) { // Change output by number of tracks
case 1: TCB0.CCMPH = ((c[0]+=cyc[0])>>8) * (env[0]>> 8) >>8; // 8x8=16bit -> 8bit
break;
case 2: TCB0.CCMPH = ( ((c[0]+=cyc[0])>>8) * (env[0]>> 9) // 8x7=15bit
+ ((c[1]+=cyc[1])>>8) * (env[1]>> 9) )>>8; // 8x7=15bit 15/15(16bit)-> 8bit
break;
case 3: TCB0.CCMPH = ( ((c[0]+=cyc[0])>>8) * (env[0]>> 9) // 8x7=15bit
+ ((c[1]+=cyc[1])>>8) * (env[1]>>10) // 8x6=14bit
+ ((c[2]+=cyc[2])>>8) * (env[2]>>10) )>>8; // 8x6=14bit 15/14/14(16bit)-> 8bit
break;
case 4: TCB0.CCMPH = ( ((c[0]+=cyc[0])>>8) * (env[0]>>10) // 8x6=14bit
+ ((c[1]+=cyc[1])>>8) * (env[1]>>10) // 8x6=14bit
+ ((c[2]+=cyc[2])>>8) * (env[2]>>10) // 8x6=14bit
+ ((c[3]+=cyc[3])>>8) * (env[3]>>10) )>>8; // 8x6=14bit 14/14/14/14(16bit)-> 8bit
}
switch( --lap ) { // Amplitude attenuation (Distribute processing per loop)
case 4: env[3] -= (env[3]>>9); break;
case 3: env[2] -= (env[2]>>9); break;
case 2: env[1] -= (env[1]>>9); break;
case 1: env[0] -= (env[0]>>9); break;
case 0: lap = 30; // every 384usec(12.8usec*30) @20MHz (Adjustable)
}
while( !TCB0.INTFLAGS ); // Waiting for TCB0 overflow (every 12.8usec(78,125Hz))
TCB0.INTFLAGS = TCB_CAPT_bm; // cleared by writing a '1'
} while( note ); // Exit if note data is 0
TCB0.CCMPH = 0; // Set output to 0
}
2023-06-25 14:13
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