Merge pull request #3 from p4ddy1/receive_midi

Receive midi
2024-12-23 12:21:30 +11:00 · 2021-01-01 11:59:35 +08:00 · 2021-01-01 11:59:35 +08:00 · f0a03436a7
parent 468ce4ed39 f7515b08f7
commit f0a03436a7
16 changed files with 432 additions and 28 deletions
--- a/.gitignore
+++ b/.gitignore
@ -1,2 +1,3 @@
 Cargo.lock
 target
+.idea
--- a/Cargo.toml
+++ b/Cargo.toml
@ -12,3 +12,7 @@ license = "MIT"
 embedded-hal = "0.2.2"
 nb = "0.1.2"
 usb-device = "0.2.3"
+
+[dependencies.num_enum]
+version = "0.5.1"
+default-features = false
--- a/README.md
+++ b/README.md
@ -4,8 +4,68 @@ usbd-midi
 A simple usb midi device class for [usb-device](https://crates.io/crates/usb-device).

 Currently this aims to be a very simple implementation, that allows the micro
-controller to send midi information to the PC.
+controller to send MIDI information to the PC and also receive MIDI information.

 This crate requires the use of a hardware driver, that implements the
 usb-device traits.

+## Example
+
+### Receive MIDI
+Turn on the integrated LED of a STM32 BluePill board as long as C2 is pressed
+```rust
+fn main() -> ! {
+    let dp = pac::Peripherals::take().unwrap();
+
+    let mut rcc = dp.RCC.constrain();
+
+    let mut gpioa = dp.GPIOA.split(&mut rcc.apb2);
+    let mut gpioc = dp.GPIOC.split(&mut rcc.apb2);
+
+    let mut led = gpioc.pc13.into_push_pull_output(&mut gpioc.crh);
+    led.set_high().unwrap();
+
+    let mut usb_dp = gpioa.pa12.into_push_pull_output(&mut gpioa.crh);
+
+    let usb = Peripheral {
+        usb: dp.USB,
+        pin_dm: gpioa.pa11,
+        pin_dp: usb_dp.into_floating_input(&mut gpioa.crh),
+    };
+
+    let usb_bus = UsbBus::new(usb);
+
+    let mut midi = MidiClass::new(&usb_bus);
+
+    let mut usb_dev = UsbDeviceBuilder::new(&usb_bus, UsbVidPid(0x16c0, 0x5e4))
+        .product("MIDI Test")
+        .device_class(USB_AUDIO_CLASS)
+        .device_sub_class(USB_MIDISTREAMING_SUBCLASS)
+        .build();
+
+    loop {
+        if !usb_dev.poll(&mut [&mut midi]) {
+            continue;
+        }
+
+        let mut buffer = [0; 64];
+
+        if let Ok(size) = midi.read(&mut buffer) {
+            let buffer_reader = MidiPacketBufferReader::new(&buffer, size);
+            for packet in buffer_reader.into_iter() {
+                if let Ok(packet) = packet {
+                    match packet.message {
+                        Message::NoteOn(Channel1, Note::C2, ..) => {
+                            led.set_low().unwrap();
+                        },
+                        Message::NoteOff(Channel1, Note::C2, ..) => {
+                            led.set_high().unwrap();
+                        },
+                        _ => {}
+                    }
+                }
+            }
+        }
+    }
+}
+```
--- a/src/data/byte/u7.rs
+++ b/src/data/byte/u7.rs
@ -2,7 +2,8 @@ use core::convert::TryFrom;
 use crate::data::byte::from_traits::{FromOverFlow,FromClamped};

 /// A primitive value that can be from 0-0x7F
-pub struct U7(u8);
+#[derive(Debug, Eq, PartialEq)]
+pub struct U7(pub(crate)u8);

 /// Error representing that this value is not a valid u7
 pub struct InvalidU7(u8);
--- a/src/data/midi/channel.rs
+++ b/src/data/midi/channel.rs
@ -3,7 +3,7 @@ use core::convert::TryFrom;
 /// The Channel is a value ranging from 0x0 to 0xF 
 /// This is a standard midi concept
 /// Note Channel1 = 0 on the wire
-#[derive(Debug,Copy,Clone)]
+#[derive(Debug,Copy,Clone, Eq, PartialEq)]
 #[repr(u8)]
 pub enum Channel {
    Channel1  = 0x0, Channel2  = 0x1, Channel3  = 0x2, Channel4  = 0x3,
--- a/src/data/midi/message/control_function.rs
+++ b/src/data/midi/message/control_function.rs
@ -0,0 +1,137 @@
+use crate::data::byte::u7::U7;
+
+#[derive(Debug, Eq, PartialEq)]
+pub struct ControlFunction(pub U7);
+
+/// Control Functions as defined in the MIDI 1.0 Specification
+/// Source: https://www.midi.org/specifications-old/item/table-3-control-change-messages-data-bytes-2
+impl ControlFunction {
+    pub const BANK_SELECT_0: Self = ControlFunction(U7(0));
+    pub const MOD_WHEEL_1: Self = ControlFunction(U7(1));
+    pub const BREATH_CONTROLLER_2: Self = ControlFunction(U7(2));
+    pub const UNDEFINED_3: Self = ControlFunction(U7(3));
+    pub const FOOT_CONTROLLER_4: Self = ControlFunction(U7(4));
+    pub const PORTAMENTO_TIME_5: Self = ControlFunction(U7(5));
+    pub const DATA_ENTRY_MSB_6: Self = ControlFunction(U7(6));
+    pub const CHANNEL_VOLUME_7: Self = ControlFunction(U7(7));
+    pub const BALANCE_8: Self = ControlFunction(U7(8));
+    pub const UNDEFINED_9: Self = ControlFunction(U7(9));
+    pub const PAN_10: Self = ControlFunction(U7(10));
+    pub const EXPRESSION_CONTROLLER_11: Self = ControlFunction(U7(11));
+    pub const EFFECT_CONTROL_1_12: Self = ControlFunction(U7(12));
+    pub const EFFECT_CONTROL_2_13: Self = ControlFunction(U7(13));
+    pub const UNDEFINED_14: Self = ControlFunction(U7(14));
+    pub const UNDEFINED_15: Self = ControlFunction(U7(15));
+    pub const GENERAL_PURPOSE_CONTROLLER_1_16: Self = ControlFunction(U7(16));
+    pub const GENERAL_PURPOSE_CONTROLLER_2_17: Self = ControlFunction(U7(17));
+    pub const GENERAL_PURPOSE_CONTROLLER_3_18: Self = ControlFunction(U7(18));
+    pub const GENERAL_PURPOSE_CONTROLLER_4_19: Self = ControlFunction(U7(19));
+    pub const UNDEFINED_20: Self = ControlFunction(U7(20));
+    pub const UNDEFINED_21: Self = ControlFunction(U7(21));
+    pub const UNDEFINED_22: Self = ControlFunction(U7(22));
+    pub const UNDEFINED_23: Self = ControlFunction(U7(23));
+    pub const UNDEFINED_24: Self = ControlFunction(U7(24));
+    pub const UNDEFINED_25: Self = ControlFunction(U7(25));
+    pub const UNDEFINED_26: Self = ControlFunction(U7(26));
+    pub const UNDEFINED_27: Self = ControlFunction(U7(27));
+    pub const UNDEFINED_28: Self = ControlFunction(U7(28));
+    pub const UNDEFINED_29: Self = ControlFunction(U7(29));
+    pub const UNDEFINED_30: Self = ControlFunction(U7(30));
+    pub const UNDEFINED_31: Self = ControlFunction(U7(31));
+    pub const LSB_FOR_BANK_SELECT_32: Self = ControlFunction(U7(32));
+    pub const LSB_FOR_MOD_WHEEL_33: Self = ControlFunction(U7(33));
+    pub const LSB_FOR_BREATH_CONTROLLER_34: Self = ControlFunction(U7(34));
+    pub const LSB_FOR_UNDEFINED_35: Self = ControlFunction(U7(35));
+    pub const LSB_FOR_FOOT_CONTROLLER_36: Self = ControlFunction(U7(36));
+    pub const LSB_FOR_PORTAMENTO_TIME_37: Self = ControlFunction(U7(37));
+    pub const LSB_FOR_DATA_ENTRY_MSB_38: Self = ControlFunction(U7(38));
+    pub const LSB_FOR_CHANNEL_VOLUME_39: Self = ControlFunction(U7(39));
+    pub const LSB_FOR_BALANCE_40: Self = ControlFunction(U7(40));
+    pub const LSB_FOR_UNDEFINED_41: Self = ControlFunction(U7(41));
+    pub const LSB_FOR_PAN_42: Self = ControlFunction(U7(42));
+    pub const LSB_FOR_EXPRESSION_CONTROLLER_43: Self = ControlFunction(U7(43));
+    pub const LSB_FOR_EFFECT_CONTROL_1_44: Self = ControlFunction(U7(44));
+    pub const LSB_FOR_EFFECT_CONTROL_2_45: Self = ControlFunction(U7(45));
+    pub const LSB_FOR_UNDEFINED_14_46: Self = ControlFunction(U7(46));
+    pub const LSB_FOR_UNDEFINED_15_47: Self = ControlFunction(U7(47));
+    pub const LSB_FOR_GENERAL_PURPOSE_CONTROLLER_1_48: Self = ControlFunction(U7(48));
+    pub const LSB_FOR_GENERAL_PURPOSE_CONTROLLER_2_49: Self = ControlFunction(U7(49));
+    pub const LSB_FOR_GENERAL_PURPOSE_CONTROLLER_3_50: Self = ControlFunction(U7(50));
+    pub const LSB_FOR_GENERAL_PURPOSE_CONTROLLER_4_51: Self = ControlFunction(U7(51));
+    pub const LSB_FOR_UNDEFINED_20_52: Self = ControlFunction(U7(52));
+    pub const LSB_FOR_UNDEFINED_21_53: Self = ControlFunction(U7(53));
+    pub const LSB_FOR_UNDEFINED_22_54: Self = ControlFunction(U7(54));
+    pub const LSB_FOR_UNDEFINED_23_55: Self = ControlFunction(U7(55));
+    pub const LSB_FOR_UNDEFINED_24_56: Self = ControlFunction(U7(56));
+    pub const LSB_FOR_UNDEFINED_25_57: Self = ControlFunction(U7(57));
+    pub const LSB_FOR_UNDEFINED_26_58: Self = ControlFunction(U7(58));
+    pub const LSB_FOR_UNDEFINED_27_59: Self = ControlFunction(U7(59));
+    pub const LSB_FOR_UNDEFINED_28_60: Self = ControlFunction(U7(60));
+    pub const LSB_FOR_UNDEFINED_29_61: Self = ControlFunction(U7(61));
+    pub const LSB_FOR_UNDEFINED_30_62: Self = ControlFunction(U7(62));
+    pub const LSB_FOR_UNDEFINED_31_63: Self = ControlFunction(U7(63));
+    pub const DAMPER_PEDAL_ON_OFF_64: Self = ControlFunction(U7(64));
+    pub const PORTAMENTO_ON_OFF_65: Self = ControlFunction(U7(65));
+    pub const SOSTENUTO_ON_OFF_66: Self = ControlFunction(U7(66));
+    pub const SOFT_PEDAL_ON_OFF_67: Self = ControlFunction(U7(67));
+    pub const LEGATO_FOOTSWITCH_68: Self = ControlFunction(U7(68));
+    pub const HOLD_2_69: Self = ControlFunction(U7(69));
+    pub const SOUND_CONTROLLER_1_70: Self = ControlFunction(U7(70));
+    pub const SOUND_CONTROLLER_2_71: Self = ControlFunction(U7(71));
+    pub const SOUND_CONTROLLER_3_72: Self = ControlFunction(U7(72));
+    pub const SOUND_CONTROLLER_4_73: Self = ControlFunction(U7(73));
+    pub const SOUND_CONTROLLER_5_74: Self = ControlFunction(U7(74));
+    pub const SOUND_CONTROLLER_6_75: Self = ControlFunction(U7(75));
+    pub const SOUND_CONTROLLER_7_76: Self = ControlFunction(U7(76));
+    pub const SOUND_CONTROLLER_8_77: Self = ControlFunction(U7(77));
+    pub const SOUND_CONTROLLER_9_78: Self = ControlFunction(U7(78));
+    pub const SOUND_CONTROLLER_10_79: Self = ControlFunction(U7(79));
+    pub const GENERAL_PURPOSE_CONTROLLER_5_80: Self = ControlFunction(U7(80));
+    pub const GENERAL_PURPOSE_CONTROLLER_6_81: Self = ControlFunction(U7(81));
+    pub const GENERAL_PURPOSE_CONTROLLER_7_82: Self = ControlFunction(U7(82));
+    pub const GENERAL_PURPOSE_CONTROLLER_8_83: Self = ControlFunction(U7(83));
+    pub const PORTAMENTO_CONTROL_84: Self = ControlFunction(U7(84));
+    pub const UNDEFINED_85: Self = ControlFunction(U7(85));
+    pub const UNDEFINED_86: Self = ControlFunction(U7(86));
+    pub const UNDEFINED_87: Self = ControlFunction(U7(87));
+    pub const HIGH_RESOLUTION_VELOCITY_PREFIX_88: Self = ControlFunction(U7(88));
+    pub const UNDEFINED_89: Self = ControlFunction(U7(89));
+    pub const UNDEFINED_90: Self = ControlFunction(U7(90));
+    pub const EFFECTS_1_DEPTH_91: Self = ControlFunction(U7(91));
+    pub const EFFECTS_2_DEPTH_92: Self = ControlFunction(U7(92));
+    pub const EFFECTS_3_DEPTH_93: Self = ControlFunction(U7(93));
+    pub const EFFECTS_4_DEPTH_94: Self = ControlFunction(U7(94));
+    pub const EFFECTS_5_DEPTH_95: Self = ControlFunction(U7(95));
+    pub const DATA_INCREMENT_96: Self = ControlFunction(U7(96));
+    pub const DATA_DECREMENT_97: Self = ControlFunction(U7(97));
+    pub const NPRN_LSB_98: Self = ControlFunction(U7(98));
+    pub const NPRN_MSB_99: Self = ControlFunction(U7(99));
+    pub const RPN_LSB_100: Self = ControlFunction(U7(100));
+    pub const UNDEFINED_101: Self = ControlFunction(U7(101));
+    pub const UNDEFINED_102: Self = ControlFunction(U7(102));
+    pub const UNDEFINED_103: Self = ControlFunction(U7(103));
+    pub const UNDEFINED_104: Self = ControlFunction(U7(104));
+    pub const UNDEFINED_105: Self = ControlFunction(U7(105));
+    pub const UNDEFINED_106: Self = ControlFunction(U7(106));
+    pub const UNDEFINED_107: Self = ControlFunction(U7(107));
+    pub const UNDEFINED_108: Self = ControlFunction(U7(108));
+    pub const UNDEFINED_109: Self = ControlFunction(U7(109));
+    pub const UNDEFINED_110: Self = ControlFunction(U7(110));
+    pub const UNDEFINED_111: Self = ControlFunction(U7(111));
+    pub const UNDEFINED_112: Self = ControlFunction(U7(112));
+    pub const UNDEFINED_113: Self = ControlFunction(U7(113));
+    pub const UNDEFINED_114: Self = ControlFunction(U7(114));
+    pub const UNDEFINED_115: Self = ControlFunction(U7(115));
+    pub const UNDEFINED_116: Self = ControlFunction(U7(116));
+    pub const UNDEFINED_117: Self = ControlFunction(U7(117));
+    pub const UNDEFINED_118: Self = ControlFunction(U7(118));
+    pub const UNDEFINED_119: Self = ControlFunction(U7(119));
+    pub const ALL_SOUND_OFF_120: Self = ControlFunction(U7(120));
+    pub const RESET_ALL_CONTROLLERS_121: Self = ControlFunction(U7(121));
+    pub const LOCAL_CONTROL_OFF_122: Self = ControlFunction(U7(122));
+    pub const ALL_NOTES_OFF_123: Self = ControlFunction(U7(123));
+    pub const OMNI_MODE_OFF_124: Self = ControlFunction(U7(124));
+    pub const OMNI_MODE_ON_125: Self = ControlFunction(U7(125));
+    pub const MONO_MODE_ON_126: Self = ControlFunction(U7(126));
+    pub const POLY_MODE_ON_127: Self = ControlFunction(U7(127));
+}
--- a/src/data/midi/message/message.rs
+++ b/src/data/midi/message/message.rs
@ -3,6 +3,10 @@ use crate::data::midi::channel::Channel;
 use crate::data::midi::notes::Note;
 use crate::data::byte::u7::U7;
 use crate::data::midi::message::raw::{Raw,Payload};
+use crate::data::byte::from_traits::FromClamped;
+use core::convert::TryFrom;
+use crate::data::usb_midi::usb_midi_event_packet::MidiPacketParsingError;
+use crate::data::midi::message::control_function::ControlFunction;

 type Velocity = U7;

@ -10,6 +14,7 @@ type Velocity = U7;
 /// Note: not current exhaustive and SysEx messages end up
 /// being a confusing case. So are currently note implemented 
 /// they are sort-of unbounded
+#[derive(Debug, Eq, PartialEq)]
 pub enum Message {
    NoteOff(Channel,Note,Velocity),
    NoteOn(Channel,Note,Velocity),
@ -17,6 +22,7 @@ pub enum Message {
    ProgramChange(Channel,U7),
    ChannelAftertouch(Channel,U7),
    PitchWheelChange(Channel,U7,U7),
+    ControlChange(Channel,ControlFunction,U7)
 }

 const NOTE_OFF_MASK              :u8 = 0b1000_0000;
@ -25,6 +31,7 @@ const POLYPHONIC_MASK           :u8 = 0b1010_0000;
 const PROGRAM_MASK               :u8 = 0b1100_0000;
 const CHANNEL_AFTERTOUCH_MASK    :u8 = 0b1101_0000;
 const PITCH_BEND_MASK            :u8 = 0b1110_0000;
+const CONTROL_CHANGE_MASK        :u8 = 0b1011_0000;

 impl From<Message> for Raw {
    fn from(value:Message) -> Raw {
@ -58,8 +65,58 @@ impl From<Message> for Raw {
                let payload = Payload::DoubleByte(lsb,msb);
                let status = PITCH_BEND_MASK | u8::from(chan);
                Raw {status , payload}
+            },
+            Message::ControlChange(chan, control_function, value) => {
+                let payload = Payload::DoubleByte(control_function.0, value);
+                let status = CONTROL_CHANGE_MASK | u8::from(chan);
+                Raw {status, payload}
            }
-                
        }
    }
 }
+
+impl<'a> TryFrom<&'a [u8]> for Message {
+    type Error = MidiPacketParsingError;
+    fn try_from(data: &[u8]) -> Result<Self, Self::Error> {
+        let status_byte = match data.get(0) {
+            Some(byte) => byte,
+            None => return Err(MidiPacketParsingError::MissingDataPacket)
+        };
+
+        let event_type = status_byte & 0b1111_0000;
+        let channel_bytes = (status_byte) & 0b0000_1111;
+
+        let channel = Channel::try_from(channel_bytes).ok().unwrap();
+
+        match event_type {
+            NOTE_ON_MASK => Ok(Message::NoteOn(channel, get_note(data)?, get_u7_at(data, 2)?)),
+            NOTE_OFF_MASK => Ok(Message::NoteOff(channel, get_note(data)?, get_u7_at(data, 2)?)),
+            POLYPHONIC_MASK => Ok(Message::PolyphonicAftertouch(channel, get_note(data)?, get_u7_at(data, 2)?)),
+            PROGRAM_MASK => Ok(Message::ProgramChange(channel, get_u7_at(data, 1)?)),
+            CHANNEL_AFTERTOUCH_MASK => Ok(Message::ChannelAftertouch(channel, get_u7_at(data, 1)?)),
+            PITCH_BEND_MASK => Ok(Message::PitchWheelChange(channel, get_u7_at(data, 1)?, get_u7_at(data, 2)?)),
+            CONTROL_CHANGE_MASK => Ok(Message::ControlChange(channel, ControlFunction(get_u7_at(data, 1)?), get_u7_at(data, 2)?)),
+            _ => Err(MidiPacketParsingError::InvalidEventType(event_type))
+        }
+    }
+}
+
+fn get_note(data: &[u8]) -> Result<Note, MidiPacketParsingError> {
+    let note_byte = get_byte_at_position(data, 1)?;
+    match Note::try_from(note_byte) {
+        Ok(note) => Ok(note),
+        Err(_) => Err(MidiPacketParsingError::InvalidNote(note_byte))
+    }
+}
+
+fn get_u7_at(data: &[u8], index: usize) -> Result<U7, MidiPacketParsingError> {
+    let data_byte = get_byte_at_position(data, index)?;
+    Ok(U7::from_clamped(data_byte))
+}
+
+fn get_byte_at_position(data: &[u8], index: usize) -> Result<u8, MidiPacketParsingError> {
+    match data.get(index) {
+        Some(byte) => Ok(*byte),
+        None => Err(MidiPacketParsingError::MissingDataPacket)
+    }
+}
--- a/src/data/midi/message/mod.rs
+++ b/src/data/midi/message/mod.rs
@ -1,3 +1,4 @@
 pub mod message;
 pub mod raw;
 pub use crate::data::midi::message::message::{Message};
+pub mod control_function;
--- a/src/data/midi/notes.rs
+++ b/src/data/midi/notes.rs
@ -1,10 +1,11 @@
 use crate::data::byte::u7::U7;
 use crate::data::byte::from_traits::FromOverFlow;
+use num_enum::TryFromPrimitive;
 /// A simple enum type that represents all the midi 'notes'
 /// note the flat versions are associated constants
 /// but can be referenced like Note::Bb3
 /// C1m is the C-1
-#[derive(Debug,Copy,Clone)]
+#[derive(Debug,Copy,Clone,TryFromPrimitive,Eq,PartialEq)]
 #[repr(u8)]
 pub enum Note {
    C1m, Cs1m, D1m, Ds1m, E1m, F1m, Fs1m, G1m, Gs1m, A1m, As1m, B1m,
--- a/src/data/usb/constants.rs
+++ b/src/data/usb/constants.rs
@ -4,7 +4,7 @@ pub const USB_CLASS_NONE : u8 = 0x00;
 pub const USB_AUDIO_CLASS: u8 = 0x01;
 pub const USB_AUDIOCONTROL_SUBCLASS: u8 = 0x01;
 pub const USB_MIDISTREAMING_SUBCLASS: u8 =0x03;
-//pub const MIDI_IN_JACK_SUBTYPE : u8 = 0x02;
+pub const MIDI_IN_JACK_SUBTYPE : u8 = 0x02;
 pub const MIDI_OUT_JACK_SUBTYPE : u8 = 0x03;
 pub const EMBEDDED : u8 = 0x01;
 pub const CS_INTERFACE: u8 = 0x24;
--- a/src/data/usb_midi/cable_number.rs
+++ b/src/data/usb_midi/cable_number.rs
@ -4,7 +4,7 @@ use crate::data::byte::u4::U4;
 /// The Cable Number (CN) is a value ranging from 0x0 to 0xF 
 /// indicating the number assignment of the Embedded MIDI Jack associated 
 /// with the endpoint that is transferring the data
-#[derive(Debug,Clone,Copy)]
+#[derive(Debug,Clone,Copy,Eq, PartialEq)]
 #[repr(u8)]
 pub enum CableNumber {
    Cable0  = 0x0, Cable1  = 0x1, Cable2  = 0x2, Cable3  = 0x3,
--- a/src/data/usb_midi/code_index_number.rs
+++ b/src/data/usb_midi/code_index_number.rs
@ -71,7 +71,8 @@ impl CodeIndexNumber {
            Message::ChannelAftertouch(_,_) => CodeIndexNumber::CHANNEL_PRESSURE,
            Message::PitchWheelChange(_,_,_) => CodeIndexNumber::PITCHBEND_CHANGE,
            Message::PolyphonicAftertouch(_,_,_) => CodeIndexNumber::POLY_KEYPRESS,
-            Message::ProgramChange(_,_) => CodeIndexNumber::PROGRAM_CHANGE
+            Message::ProgramChange(_,_) => CodeIndexNumber::PROGRAM_CHANGE,
+            Message::ControlChange(_,_,_) => CodeIndexNumber::CONTROL_CHANGE
        }
    }
 }
--- a/src/data/usb_midi/midi_packet_reader.rs
+++ b/src/data/usb_midi/midi_packet_reader.rs
@ -0,0 +1,36 @@
+use core::convert::TryFrom;
+use crate::data::usb_midi::usb_midi_event_packet::{UsbMidiEventPacket, MidiPacketParsingError};
+use crate::midi_device::{MAX_PACKET_SIZE, MIDI_PACKET_SIZE};
+
+pub struct MidiPacketBufferReader<'a> {
+    buffer: &'a [u8; MAX_PACKET_SIZE],
+    position: usize,
+    raw_bytes_received: usize
+}
+
+impl<'a> MidiPacketBufferReader<'a> {
+    pub fn new(buffer: &'a [u8; MAX_PACKET_SIZE], raw_bytes_received: usize) -> Self {
+        MidiPacketBufferReader {
+            buffer,
+            position: 0,
+            raw_bytes_received
+        }
+    }
+}
+
+impl<'a> Iterator for MidiPacketBufferReader<'a> {
+    type Item = Result<UsbMidiEventPacket, MidiPacketParsingError>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.position <= MAX_PACKET_SIZE && self.position < self.raw_bytes_received {
+            let packet = match self.buffer.get(self.position .. (self.position + MIDI_PACKET_SIZE)) {
+                Some(packet) => Some(UsbMidiEventPacket::try_from(packet)),
+                None => None
+            };
+
+            self.position += MIDI_PACKET_SIZE;
+            return packet;
+        }
+        None
+    }
+}
--- a/src/data/usb_midi/mod.rs
+++ b/src/data/usb_midi/mod.rs
@ -1,3 +1,4 @@
 pub mod usb_midi_event_packet;
 pub mod cable_number;
 pub mod code_index_number;
+pub mod midi_packet_reader;
--- a/src/data/usb_midi/usb_midi_event_packet.rs
+++ b/src/data/usb_midi/usb_midi_event_packet.rs
@ -3,11 +3,13 @@ use crate::data::usb_midi::code_index_number::CodeIndexNumber;
 use crate::data::midi::message::Message;
 use crate::data::byte::u4::U4;
 use crate::data::midi::message::raw::{Payload,Raw};
+use core::convert::TryFrom;


 /// A packet that communicates with the host
 /// Currently supported is sending the specified normal midi
 /// message over the supplied cable number
+#[derive(Debug,Eq, PartialEq)]
 pub struct UsbMidiEventPacket {
    pub cable_number : CableNumber,
    pub message: Message
@ -37,6 +39,42 @@ impl From<UsbMidiEventPacket> for [u8;4] {
    }
 }

+#[derive(Debug)]
+pub enum MidiPacketParsingError {
+    InvalidNote(u8),
+    InvalidCableNumber(u8),
+    InvalidEventType(u8),
+    MissingDataPacket
+}
+
+impl TryFrom<&[u8]> for UsbMidiEventPacket {
+    type Error = MidiPacketParsingError;
+
+    fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
+        let raw_cable_number= match value.get(0) {
+            Some(byte) => *byte >> 4,
+            None => return Err(MidiPacketParsingError::MissingDataPacket)
+        };
+
+        let cable_number = match CableNumber::try_from(u8::from(raw_cable_number)) {
+            Ok(val) => val,
+            _ => return Err(MidiPacketParsingError::InvalidCableNumber(raw_cable_number))
+        };
+
+        let message_body = match value.get(1..) {
+            Some(bytes) => bytes,
+            None => return Err(MidiPacketParsingError::MissingDataPacket)
+        };
+
+        let message = Message::try_from(message_body)?;
+
+        Ok(UsbMidiEventPacket {
+            cable_number,
+            message
+        })
+    }
+}
+
 impl UsbMidiEventPacket{

    pub fn from_midi(cable:CableNumber, midi:Message)
@ -47,3 +85,59 @@ impl UsbMidiEventPacket{
        }
    }
 }
+
+#[cfg(test)]
+mod tests {
+    use core::convert::TryFrom;
+    use crate::data::usb_midi::usb_midi_event_packet::UsbMidiEventPacket;
+    use crate::data::midi::channel::Channel::{Channel1, Channel2};
+    use crate::data::midi::notes::Note;
+    use crate::data::byte::u7::U7;
+    use crate::data::midi::message::Message;
+    use crate::data::usb_midi::cable_number::CableNumber::{Cable0,Cable1};
+    use crate::data::midi::message::control_function::ControlFunction;
+
+    macro_rules! decode_message_test {
+        ($($id:ident:$value:expr,)*) => {
+            $(
+                #[test]
+                fn $id() {
+                    let (usb_midi_data_packet,expected) = $value;
+                    let message = UsbMidiEventPacket::try_from(&usb_midi_data_packet[..]).unwrap();
+                    assert_eq!(expected, message);
+                }
+            )*
+        }
+    }
+
+    decode_message_test! {
+        note_on: ([9, 144, 36, 127], UsbMidiEventPacket {
+            cable_number: Cable0,
+            message: Message::NoteOn(Channel1, Note::C2, U7(127))
+        }),
+        note_off: ([8, 128, 36, 0], UsbMidiEventPacket {
+            cable_number: Cable0,
+            message: Message::NoteOff(Channel1, Note::C2, U7(0))
+        }),
+        polyphonic_aftertouch: ([10, 160, 36, 64], UsbMidiEventPacket {
+            cable_number: Cable0,
+            message: Message::PolyphonicAftertouch(Channel1, Note::C2, U7(64))
+        }),
+        program_change: ([28, 192, 127, 0], UsbMidiEventPacket {
+            cable_number: Cable1,
+            message: Message::ProgramChange(Channel1, U7(127))
+        }),
+        channel_aftertouch: ([13, 208, 127, 0], UsbMidiEventPacket {
+            cable_number: Cable0,
+            message: Message::ChannelAftertouch(Channel1, U7(127))
+        }),
+        pitch_wheel: ([14, 224, 64, 32], UsbMidiEventPacket {
+            cable_number: Cable0,
+            message: Message::PitchWheelChange(Channel1, U7(64), U7(32))
+        }),
+        control_change: ([11, 177, 1, 32], UsbMidiEventPacket {
+            cable_number: Cable0,
+            message: Message::ControlChange(Channel2, ControlFunction::MOD_WHEEL_1, U7(32))
+        }),
+    }
+}
--- a/src/midi_device.rs
+++ b/src/midi_device.rs
@ -1,21 +1,28 @@
 use usb_device::class_prelude::*;
 use usb_device::Result;
 use crate::data::usb::constants::*;
-use crate::data::usb_midi::usb_midi_event_packet::UsbMidiEventPacket;
+use crate::data::usb_midi::usb_midi_event_packet::{UsbMidiEventPacket, MidiPacketParsingError};

-//const MIDI_IN_SIZE: u8 = 0x06;
+const MIDI_IN_SIZE: u8 = 0x06;
 const MIDI_OUT_SIZE: u8 = 0x09;

+pub const MIDI_PACKET_SIZE: usize = 4;
+pub const MAX_PACKET_SIZE: usize = 64;
+
 ///Note we are using MidiIn here to refer to the fact that
 ///The Host sees it as a midi in device
 ///This class allows you to send data in
 pub struct MidiClass<'a,B: UsbBus> {
    standard_ac: InterfaceNumber,
    standard_mc: InterfaceNumber,
-    //standard_bulkout: EndpointOut<'a, B>,
+    standard_bulkout: EndpointOut<'a, B>,
    standard_bulkin: EndpointIn<'a,B>
 }

+pub enum MidiReadError {
+    ParsingFailed(MidiPacketParsingError),
+    UsbError(UsbError)
+}

 impl<B: UsbBus> MidiClass<'_, B> {
    /// Creates a new MidiClass with the provided UsbBus
@ -23,16 +30,19 @@ impl<B: UsbBus> MidiClass<'_, B> {
        MidiClass {
            standard_ac: alloc.interface(),
            standard_mc: alloc.interface(),
-            //standard_bulkout : alloc.bulk(64),
-            standard_bulkin: alloc.bulk(64)
+            standard_bulkout : alloc.bulk(MAX_PACKET_SIZE as u16),
+            standard_bulkin: alloc.bulk(MAX_PACKET_SIZE as u16)
        }
    }

    pub fn send_message(&mut self, usb_midi:UsbMidiEventPacket) -> Result<usize> {
-        let bytes : [u8;4] = usb_midi.into();
+        let bytes : [u8;MIDI_PACKET_SIZE] = usb_midi.into();
        self.standard_bulkin.write(&bytes)
    }

+    pub fn read(&mut self, buffer: &mut [u8]) -> Result<usize> {
+        self.standard_bulkout.read(buffer)
+    }
 }

 impl<B: UsbBus> UsbClass<B> for MidiClass<'_, B> {
@ -82,7 +92,7 @@ impl<B: UsbBus> UsbClass<B> for MidiClass<'_, B> {
    
        //JACKS

-/*         writer.write(
+        writer.write(
            CS_INTERFACE,
            &[
                MIDI_IN_JACK_SUBTYPE,
@ -90,7 +100,7 @@ impl<B: UsbBus> UsbClass<B> for MidiClass<'_, B> {
                0x01, // id
                0x00
            ]
-        )?; */
+        )?;

        writer.write (
            CS_INTERFACE,
@ -105,7 +115,7 @@ impl<B: UsbBus> UsbClass<B> for MidiClass<'_, B> {
            ]
        )?;

-/*         writer.endpoint(&self.standard_bulkout)?;
+        writer.endpoint(&self.standard_bulkout)?;

        writer.write(
            CS_ENDPOINT,
@ -114,7 +124,7 @@ impl<B: UsbBus> UsbClass<B> for MidiClass<'_, B> {
                0x01,
                0x01
            ]
-        )?; */
+        )?;

        writer.endpoint(&self.standard_bulkin)?;