ivan-torvalds-GuitarPedal/Software/midi.h

//
// MIDI connection code
//

// MIDI Control Change (CC) constants
#define MIDI_CC_POT_START        10 // CC 10-19 map to pots 0-9
#define MIDI_CC_GLOBAL_ENABLE    20
#define MIDI_CC_EFFECT_ENABLE    21
#define MIDI_CC_ACTIVE_POT       22

#define MIDI_CC_EFFECT_INTENSE   30
#define MIDI_CC_AUDIO_CLIPPING   31
#define MIDI_CC_CPU_LATENCY      32

extern int current_midi_effect_idx;

//
// USB-MIDI 1.0 packs everything into four bytes: a cable number in the
// high nibble of the first byte - always zero here - and a Code Index
// Number in the low nibble, then up to three bytes of the message
// itself.  The CIN says what kind of message it is and, with it, how
// many of those three bytes are real.  0x0 and 0x1 are reserved and
// mean nothing to a host.
//
// Both directions of the hardware MIDI port need this, one to build a
// CIN and one to take it apart, so keep the two halves next to each
// other where they can be checked against one another.
//

// How many of the three data bytes a CIN actually carries
static inline int midi_cin_length(uint8_t cin)
{
	switch (cin) {
	case 0x5:	// single-byte system common, or SysEx ending on one
	case 0xF:	// single byte
		return 1;
	case 0x2:	// two-byte system common
	case 0x6:	// SysEx ending on two
	case 0xC:	// program change
	case 0xD:	// channel pressure
		return 2;
	case 0x3:	// three-byte system common
	case 0x4:	// SysEx start or continue
	case 0x7:	// SysEx ending on three
	case 0x8:	// note off
	case 0x9:	// note on
	case 0xA:	// poly key pressure
	case 0xB:	// control change
	case 0xE:	// pitch bend
		return 3;
	default:	// 0x0 and 0x1 are reserved
		return 0;
	}
}

// The CIN a status byte belongs in.  Not for SysEx, whose CIN depends
// on where in the stream the packet falls rather than on any one byte.
static inline uint8_t midi_status_cin(uint8_t status)
{
	if (status >= 0xF8)		// real time
		return 0xF;
	if (status >= 0xF0) {
		switch (status) {
		case 0xF1:		// MIDI time code
		case 0xF3:		// song select
			return 0x2;
		case 0xF2:		// song position
			return 0x3;
		default:		// tune request, and friends
			return 0x5;
		}
	}
	// Channel voice: the CIN is simply the top nibble
	return status >> 4;
}

bool handle_midi_packet(const uint8_t packet[4]);
void usb_midi_poll(void);
bool usb_midi_write(const uint8_t packet[4]);
void uart_midi_write(const uint8_t packet[4]);

static inline void send_midi_cc(uint8_t cc, uint8_t val)
{
	uint8_t packet[4] = { 0x0B, 0xB0, cc, val };
	usb_midi_write(packet);
	uart_midi_write(packet);
}

static inline void send_sysex_set_param(uint8_t eff_id, uint8_t pot_idx, uint8_t val)
{
	// F0 7D 03 <eff_id> <pot_idx> <val> F7
	uint8_t p1[4] = { 0x04, 0xF0, 0x7D, 0x03 };
	uint8_t p2[4] = { 0x04, eff_id, pot_idx, val };
	uint8_t p3[4] = { 0x05, 0xF7, 0, 0 };
	usb_midi_write(p1);
	usb_midi_write(p2);
	usb_midi_write(p3);
}

static inline void send_midi_pc(uint8_t pc)
{
	uint8_t packet[4] = { 0x0C, 0xC0, pc, 0 };
	usb_midi_write(packet);
	uart_midi_write(packet);
}

static inline void send_midi_note_on(uint8_t ch, uint8_t note, uint8_t vel)
{
	uint8_t packet[4] = { 0x09, 0x90 | (ch & 0x0F), note, vel };
	usb_midi_write(packet);
	uart_midi_write(packet);
}

static inline void send_midi_note_off(uint8_t ch, uint8_t note, uint8_t vel)
{
	uint8_t packet[4] = { 0x08, 0x80 | (ch & 0x0F), note, vel };
	usb_midi_write(packet);
	uart_midi_write(packet);
}

static inline void send_midi_pitch_bend(uint8_t ch, int16_t bend)
{
	uint16_t val = bend + 8192;
	uint8_t packet[4] = { 0x0E, 0xE0 | (ch & 0x0F), val & 0x7F, (val >> 7) & 0x7F };
	usb_midi_write(packet);
	uart_midi_write(packet);
}

static inline void send_midi_channel_pressure(uint8_t ch, uint8_t pressure)
{
	uint8_t packet[4] = { 0x0D, 0xD0 | (ch & 0x0F), pressure & 0x7F, 0 };
	usb_midi_write(packet);
	uart_midi_write(packet);
}