diff options
Diffstat (limited to 'floppyMusic/midi.c')
| -rw-r--r-- | floppyMusic/midi.c | 124 |
1 files changed, 106 insertions, 18 deletions
diff --git a/floppyMusic/midi.c b/floppyMusic/midi.c index ff70a95..ae99371 100644 --- a/floppyMusic/midi.c +++ b/floppyMusic/midi.c @@ -5,38 +5,126 @@ * Author: Jonas */ + /* + Octave|| Note Numbers + # || + || C | C# | D | D# | E | F | F# | G | G# | A | A# | B + ----------------------------------------------------------------------------- + 0 || 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 + 1 || 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 + 2 || 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 + 3 || 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 + 4 || 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 + 5 || 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 + 6 || 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 + 7 || 84 | 85 | 86 | 87 | 88 | 89 | 90 | 91 | 92 | 93 | 94 | 95 + 8 || 96 | 97 | 98 | 99 | 100 | 101 | 102 | 103 | 104 | 105 | 106 | 107 + 9 || 108 | 109 | 110 | 111 | 112 | 113 | 114 | 115 | 116 | 117 | 118 | 119 + 10 || 120 | 121 | 122 | 123 | 124 | 125 | 126 | 127 | + */ + #include "midi.h" -void midi_setup() -{ - uart_init(9600); -} +extern const uint16_t midi_code_frequency_table[] = {8,9,9,10,10,11,12,12,13,14,15,15,16,17,18,19,21,22,23,25,26,28,29,31,33,35,37,39,41,44,46,49,52,55,58,62,65,69,73,78,82,87,93,98,104,110,117,123,131,139,147,156,165,175,185,196,208,220,233,247,262,277,294,311,330,349,370,392,415,440,466,494,523,554,587,622,659,698,740,784,831,880,932,988,1047,1109,1175,1245,1319,1397,1480,1568,1661,1760,1865,1976,2093,2217,2349,2489,2637,2794,2960,3136,3322,3520,3729,3951,4186,4435,4699,4978,5274,5588,5920,6272}; -void midi_recieve(struct midi_command *_command) +ISR(USART_RXC_vect) { - if(!(UCSRB & (1<<RXEN))) //Return if UART reciever not enabled - return; - + cli(); char status, data1, data2; char command, channel, note, velocity; - status = uart_recieve(); - data1 = uart_recieve(); - data2 = uart_recieve(); + //read data from interface + status = midi_recieve(); + data1 = midi_recieve(); + data2 = midi_recieve(); - command = status & 0x0f; //Mask out last 4 bits + sei(); + + //split data + command = status & 0x0f; //Mask out last 4 bits channel = (status >> 4) & 0x0f; // Shift channel into first 4 bits; note = data1; velocity = data2; - _command->command = command; - _command->channel=channel; - _command->note = note; - _command->velocity = velocity; + switch(command) + { + case 0x08: //Note off + midi_update_note(note, 0); + break; + midi_update_note(note, 1); + case 0x09: //Note on + + break; + + case 0x0A: //Note Fade Out + //unused + break; + + case 0x0B: //Control Change + //unused + break; + + case 0x0C: //Channel Fade Out + //unused + break; + + case 0x0E: //Note Pitch change + //unused + break; + } + } -void midi_send(struct midi_command _command) +void midi_setup() { + midi_active_channels = 0x00; + + //UART init + unsigned int ubrr = (F_CPU / (16 * _MIDI_LINK_SPEED)) - 1; + + UBRRH = (unsigned char) (ubrr>>8) & 0xff; + UBRRL = (unsigned char) ubrr & 0xff; + + UCSRB = (1<<RXEN) | (1<<TXEN); + UCSRC = (1<<URSEL) | (1<<USBS) | (3<<UCSZ0); + + UCSRB |= (1<<RXCIE); //enable interrupt +} + + char midi_recieve() + { + while(!(UCSRA & (1<<RXC))); //Wait for data + + return UDR; + } + + void midi_update_note(uint16_t _note, uint8_t _status) + { + if(_status) //Note on + { + int i; + for(i = 0; i < 8; i++) //search for first free channel + if(!(midi_active_channels & (1<<i))) + break; + + midi_current_notes[i] = _note; //write current note to channel + midi_active_channels |= (1<<i); //set channel active + floppy_set_frequency(i, floppy_calc_freq(midi_code_frequency_table[_note]) ); //play note + } -}
\ No newline at end of file + else //Note off + { + int i; + for(i = 0; i < 8; i++) //search for active channel playing _note + { + if(midi_current_notes[i] == _note) + { + floppy_set_frequency(i, 0); //mute + midi_current_notes[i] = 0xff; //unset current, 0xff is outside MIDI standards + midi_active_channels &= ~(1<<i); //unset channel active + break; + } + } + } + } |