ARDUINO DCO with MIDI

1// MIDI DCO w/ tone(); & saw DAC
2
3#include <SPI.h>
4
5// pins
6byte note = 8;              // note pin
7byte cs = 10;               // DAC CS pin
8byte gate = 4;              // gate pin
9byte mute = 5;              // mute the SAW
10byte s0 = 6;                // 4512 S0
11byte s1 = 7;                // 4512 S1
12// values
13float tune;                 // tune value
14int pot;                    // tune pot
15word value;                 // actual DAC value
16byte mid[3];                // MIDI data
17byte midimin = 12;          // min. MIDI note
18byte midimax = 96;          // max. MIDI note
19
20const word freq[]{0,
21523,554,587,622,659,698,740,784,831,880,932,988,
221047,1109,1175,1245,1319,1397,1480,1568,1661,1760,1865,1976,
232093,2217,2349,2489,2637,2794,2960,3136,3322,3520,3729,3951,
244186,4435,4699,4978,5274,5588,5920,6272,6645,7040,7459,7902,
254186,4435,4699,4978,5274,5588,5920,6272,6645,7040,7459,7902,
264186,4435,4699,4978,5274,5588,5920,6272,6645,7040,7459,7902,
274186,4435,4699,4978,5274,5588,5920,6272,6645,7040,7459,7902,
288372};
29
30const byte divider[]{0,
313,3,3,3,3,3,3,3,3,3,3,3,
323,3,3,3,3,3,3,3,3,3,3,3,
333,3,3,3,3,3,3,3,3,3,3,3,
343,3,3,3,3,3,3,3,3,3,3,3,
352,2,2,2,2,2,2,2,2,2,2,2,
361,1,1,1,1,1,1,1,1,1,1,1,
370,0,0,0,0,0,0,0,0,0,0,0,
380};
39
40
41void setup() 
42{
43pinMode(cs,OUTPUT);
44pinMode(gate,OUTPUT);
45pinMode(note,OUTPUT);
46pinMode(A0,INPUT);
47pinMode(mute,OUTPUT);
48pinMode(s0,OUTPUT);
49pinMode(s1,OUTPUT);
50
51digitalWrite(gate,LOW);
52digitalWrite(cs,HIGH);
53digitalWrite(mute,LOW);
54
55Serial.begin(31250);
56SPI.begin();
57DAC(0);
58}
59
60void DAC(word value)
61{
62        digitalWrite(cs,LOW);    
63        SPI.beginTransaction(SPISettings(4000000,MSBFIRST,SPI_MODE0));
64        bitWrite(value,15,LOW);   // bit 15 - dual DAC selector - LOW
65        bitWrite(value,14,LOW);   // bit 14 - buffer - LOW
66        bitWrite(value,13,HIGH);  // bit 13 - double GAIN - HIGH
67        bitWrite(value,12,HIGH);  // bit 12 - output shut down - HIGH    
68        SPI.transfer(highByte(value));
69        SPI.transfer(lowByte(value));
70        SPI.endTransaction();
71        digitalWrite(cs,HIGH);
72        bitClear(value,15);
73        bitClear(value,14);
74        bitClear(value,13);
75        bitClear(value,12); 
76}
77
78// noteOn  = 144
79// noteOff = 128
80
81void loop() 
82{
83midicomm:
84if (Serial.available() == 1)
85  {
86    mid[0] = Serial.read();
87    if (bitRead(mid[0],7) == HIGH && bitRead(mid[0],6) == LOW && bitRead(mid[0],5) == LOW) goto midinote;
88  }
89  else
90  {
91    goto midicomm;
92  }
93       
94midinote:
95if (Serial.available() == 1)
96  {
97    mid[1] = Serial.read();
98    if (bitRead(mid[1],7) == HIGH && bitRead(mid[1],6) == LOW && bitRead(mid[1],5) == LOW) 
99      {
100        mid[0] = mid[1];
101        goto midinote;
102      }
103    pot = (analogRead(A0) / 4) - 128 ;
104    tune = 1 / ((float(pot) / 1100) + 1);
105  }
106  else
107  {
108    goto midinote;
109  }
110
111midivol:
112if (Serial.available() == 1)
113  {
114    mid[2] = Serial.read();
115    if (bitRead(mid[2],7) == HIGH && bitRead(mid[2],6) == LOW && bitRead(mid[2],5) == LOW) 
116    {
117      mid[0] = mid[2];
118      goto midinote;
119    }
120  }
121  else
122  {
123    goto midivol;
124  }
125
126if (bitRead(mid[0],4) == HIGH && mid[2] > 0 && mid[1] >= midimin && mid[1] <= midimax)
127  {
128    // note ON
129    tone(note,word(freq[mid[1] - midimin + 1] * tune));
130    value = ((mid[1] - midimin + 1) * 34) + 1000 ;
131    DAC(value);
132    digitalWrite(s0,bitRead(divider[mid[1] - midimin + 1],0));
133    digitalWrite(s1,bitRead(divider[mid[1] - midimin + 1],1));
134    digitalWrite(gate,HIGH);
135    digitalWrite(mute,HIGH);
136  }
137  else
138  {
139    // note OFF
140    digitalWrite(mute,LOW);
141    digitalWrite(gate,LOW);
142    noTone(note);
143    DAC(0);
144    digitalWrite(s0,LOW);
145    digitalWrite(s1,LOW);
146  }      
147}