midi.c File Reference

MIDI message transceiver. More...

#include <stddef.h>
#include <avr/interrupt.h>
#include <avr/io.h>
#include "gpio.h"
#include "midi.h"
#include "leds.h"

Include dependency graph for midi.c:

Functions
void	init_midi_module (const struct midi_config *const config)
	Initializes the MIDI transceiver module. More...
enum midi_channel	read_midi_channel_from_jumpers (const struct jumpers *jumpers)
	Reads the MIDI channel configuration from the solder jumpers. More...
void	send_control_change (midi_value_t controller, midi_value_t value)
	Sends a control change message. More...
void	send_midi_message (enum midi_channel channel, enum midi_message_type type, midi_value_t data0, midi_value_t data1)
	Sends an arbitrary MIDI message. More...
void	send_note_off (midi_value_t note, midi_value_t velocity)
	Sends a note off message. More...
void	send_note_on (midi_value_t note, midi_value_t velocity)
	Sends a note on message. More...
void	send_program_change (midi_value_t pnum)
	Sends a program change message. More...
void	set_midi_rx_channel (enum midi_channel channel)
	Updates the midi receive channel. More...
void	set_midi_tx_channel (enum midi_channel channel)
	Updates the midi transmit channel. More...
void	set_omni_mode (bool enable)
	Puts the device into Omni mode. More...
static void	handle_status_byte (midi_value_t data)
	Updates the MIDI state machine according to the supplied data byte. More...
	ISR (USARTE0_RXC_vect)
	Main interrupt service routine for incoming MIDI messages. More...

Variables
static struct midi_event_handlers *	event_handlers
	The MIDI event handlers. More...
static enum midi_state	midi_state = MIDI_STATE_IDLE
	Current state of the MIDI state machine. More...
static bool	omni_mode
	Omni mode state. More...
static enum midi_channel	rx_channel
	The MIDI receive channel. More...
static enum midi_channel	tx_channel
	The MIDI transmit channel. More...
static bool	signal_rx
	If set to true, the red on-board LED flashes on every received MIDI message. More...

Detailed Description

MIDI message transceiver.

Function Documentation

handle_status_byte()

static void handle_status_byte ( midi_value_t  data )

static

Updates the MIDI state machine according to the supplied data byte.

Parameters

data	the MIDI data byte to be parsed

init_midi_module()

void init_midi_module

(

const struct midi_config *

config

)

Initializes the MIDI transceiver module.

Configures the UART, enables the RXC interrupt and registers MIDI message handlers.

Parameters

config

the MIDI module configuration to apply

ISR()

ISR

(

USARTE0_RXC_vect

)

Main interrupt service routine for incoming MIDI messages.

This routine reads and parses MIDI data arriving on the USART and calls the callback functions registered during module initialization. For the time being, all MIDI packets are handled, regardless of the MIDI channel, so uMIDI devices are effectively in OMNI mode.

See also

init_midi_module

read_midi_channel_from_jumpers()

enum midi_channel read_midi_channel_from_jumpers

(

const struct jumpers *

jumpers

)

Reads the MIDI channel configuration from the solder jumpers.

Parameters

jumpers

the the solder jumpers configuration struct

Returns

the selected MIDI channel

send_control_change()

void send_control_change	(	midi_value_t	controller,
		midi_value_t	value
	)

Sends a control change message.

Parameters

controller	the MIDI controller number
value	the new value for the controller

send_midi_message()

void send_midi_message	(	enum midi_channel	channel,
		enum midi_message_type	type,
		midi_value_t	data0,
		midi_value_t	data1
	)

Sends an arbitrary MIDI message.

If the second data byte is not required for the specified message type, the parameter is simply ignored.

Parameters

channel	the MIDI channel to send on
type	the type of the MIDI message to send
data0	the first data byte (e.g. MIDI controller number for a control change)
data1	the second data byte (optional, e.g. value for a control change)

send_note_off()

void send_note_off	(	midi_value_t	note,
		midi_value_t	velocity
	)

Sends a note off message.

Parameters

note	the MIDI note number
velocity	velocity of the key press

send_note_on()

void send_note_on	(	midi_value_t	note,
		midi_value_t	velocity
	)

Sends a note on message.

Parameters

note	the MIDI note number
velocity	velocity of the key press

send_program_change()

void send_program_change

(

midi_value_t

program

)

Sends a program change message.

Parameters

program

the new MIDI program to load

set_midi_rx_channel()

void set_midi_rx_channel

(

enum midi_channel

channel

)

Updates the midi receive channel.

Parameters

channel

the channel to listen on

set_midi_tx_channel()

void set_midi_tx_channel

(

enum midi_channel

channel

)

Updates the midi transmit channel.

Parameters

channel

the channel to talk on

set_omni_mode()

void set_omni_mode

(

bool

enable

)

Puts the device into Omni mode.

In Omni mode the device handles all received MIDI messages regardless of the channel. When not in Omni mode, only messages on the configured receive channel are processed.

Parameters

enable

if true, Omni mode is enabled; if false, it is disabled

Variable Documentation

event_handlers

struct midi_event_handlers* event_handlers

static

The MIDI event handlers.

See also

init_midi_module

midi_state

enum midi_state midi_state = MIDI_STATE_IDLE

static

Current state of the MIDI state machine.

omni_mode

bool omni_mode

static

Omni mode state.

See also

init_midi_module

rx_channel

enum midi_channel rx_channel

static

The MIDI receive channel.

See also

init_midi_module

signal_rx

bool signal_rx

static

If set to true, the red on-board LED flashes on every received MIDI message.

See also

init_midi_module

tx_channel

enum midi_channel tx_channel

static

The MIDI transmit channel.

See also

init_midi_module