添加一些关于midi播放的项目

2025-03-24 14:30:56 +08:00
parent e31eb22077
commit 498b4ef13b
699 changed files with 186162 additions and 1 deletions
@@ -0,0 +1,135 @@
+/*
+ *	Arduino MIDI Player
+ *
+ *	Setup Arduino and use timer2 to synthesize and output sine wave
+ *
+ *	2016 by ilufang
+ */
+
+/*
+ * Part of this file contains code modified/referenced from
+ * http://interface.khm.de/index.php/lab/interfaces-advanced/arduino-dds-sinewave-generator/
+ *
+ * DDS Sine Generator mit ATMEGS 168
+ * Timer2 generates the  31250 KHz Clock Interrupt
+ *
+ * KHM 2009 /  Martin Nawrath
+ * Kunsthochschule fuer Medien Koeln
+ * Academy of Media Arts Cologne
+ */
+
+#include "avr/pgmspace.h"
+
+#include "midi2wave.h"
+
+#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
+#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
+
+#define POW2_32 4294967296
+#define refclk 31376.6 // Reference clock
+
+// variables in interrupt service
+volatile int timer_tick = 0; // seeking position in wave
+volatile unsigned char timer_micro = 0; // timing counter in microseconds
+volatile unsigned short timer_milli = 0; // timing counter in milliseconds
+volatile unsigned long phaccu_1, phaccu_2, phaccu_3, phaccu_4, phaccu_5, phaccu_6, phaccu_7, phaccu_8; // phase accumulator
+volatile unsigned long tword_m_1, tword_m_2, tword_m_3, tword_m_4, tword_m_5, tword_m_6, tword_m_7, tword_m_8; // DDS tuning word m
+unsigned long phaccu_all;
+
+void setup()
+{
+	Serial.begin(9600);
+	Serial.println("Hello");
+	for (int i = 2; i <= 8; ++i)
+		pinMode(i,OUTPUT); // LED output
+
+	pinMode(11,OUTPUT); // PWM Wave output
+	setupMidi();
+	setupTimer2();
+}
+
+void loop()
+{
+	while(true) {
+		if (timer_milli > event_length) { // wait for the next midi event
+			cbi (TIMSK2,TOIE2);
+			loadNextEvent();
+			// calculate new DDS tuning word
+			tword_m_1=POW2_32*PIANO(active_keys[0])/refclk;
+			tword_m_2=POW2_32*PIANO(active_keys[1])/refclk;
+			tword_m_3=POW2_32*PIANO(active_keys[2])/refclk;
+			tword_m_4=POW2_32*PIANO(active_keys[3])/refclk;
+			if (!tword_m_1) phaccu_1 = 0;
+			if (!tword_m_2) phaccu_2 = 0;
+			if (!tword_m_3) phaccu_3 = 0;
+			if (!tword_m_4) phaccu_4 = 0;
+			timer_milli=0;
+			sbi (TIMSK2,TOIE2);
+		}
+	}
+}
+
+/*
+ * timer2 setup
+ *
+ * set pre-scaler to 1, PWM mode to phase correct PWM,  16000000/510 = 31372.55 Hz clock
+ */
+void setupTimer2() {
+	// Timer2 Clock Pre-scaler to : 1
+	sbi (TCCR2B, CS20);
+	cbi (TCCR2B, CS21);
+	cbi (TCCR2B, CS22);
+
+	// Timer2 PWM Mode set to Phase Correct PWM
+	cbi (TCCR2A, COM2A0); // clear Compare Match
+	sbi (TCCR2A, COM2A1);
+
+	sbi (TCCR2A, WGM20); // Mode 1 / Phase Correct PWM
+	cbi (TCCR2A, WGM21);
+	cbi (TCCR2B, WGM22);
+
+	// initialize DDS tuning word
+	tword_m_1=0;
+	tword_m_2=0;
+	tword_m_3=0;
+	tword_m_4=0;
+
+	// disable Timer0 interrupts to avoid timing distortion
+	cbi (TIMSK0,TOIE0);
+	// start Timer2!
+	sbi (TIMSK2,TOIE2);
+
+}
+
+/*
+ * Timer2 Interrupt Service
+ *
+ * Running at 31372,550 KHz = 32uSec
+ * this is the timebase REFCLOCK for the DDS generator
+ * FOUT = (M (REFCLK)) / (2 exp 32)
+ * runtime : 8 microseconds ( inclusive push and pop)
+ */
+ISR(TIMER2_OVF_vect) {
+	// soft DDS, phase accumulator with 32 bits
+	phaccu_1 += tword_m_1;
+	phaccu_2 += tword_m_2;
+	phaccu_3 += tword_m_3;
+	phaccu_4 += tword_m_4;
+	phaccu_5 += tword_m_5;
+
+	// use upper 8 bits for phase accumulator as frequency information
+	int phaccu_all = sine[phaccu_1>>24];
+	phaccu_all += sine[phaccu_2>>24];
+	phaccu_all += sine[phaccu_3>>24];
+	phaccu_all += sine[phaccu_4>>24];
+	phaccu_all += sine[phaccu_5>>24];
+
+	// Write to PWM port 11
+	OCR2A = phaccu_all/KEYBUF_SIZE;
+
+	// Increment timing counter
+	if(++timer_micro == 31) {
+		++timer_milli;
+		timer_micro=0;
+	}
+}