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-rw-r--r--examples/rp/src/bin/usb_midi.rs110
1 files changed, 110 insertions, 0 deletions
diff --git a/examples/rp/src/bin/usb_midi.rs b/examples/rp/src/bin/usb_midi.rs
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+++ b/examples/rp/src/bin/usb_midi.rs
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1//! This example shows how to use USB (Universal Serial Bus) in the RP2040 chip.
2//!
3//! This creates a USB MIDI device that echoes MIDI messages back to the host.
4
5#![no_std]
6#![no_main]
7#![feature(type_alias_impl_trait)]
8
9use defmt::{info, panic};
10use embassy_executor::Spawner;
11use embassy_futures::join::join;
12use embassy_rp::bind_interrupts;
13use embassy_rp::peripherals::USB;
14use embassy_rp::usb::{Driver, Instance, InterruptHandler};
15use embassy_usb::class::midi::MidiClass;
16use embassy_usb::driver::EndpointError;
17use embassy_usb::{Builder, Config};
18use {defmt_rtt as _, panic_probe as _};
19
20bind_interrupts!(struct Irqs {
21 USBCTRL_IRQ => InterruptHandler<USB>;
22});
23
24#[embassy_executor::main]
25async fn main(_spawner: Spawner) {
26 info!("Hello world!");
27
28 let p = embassy_rp::init(Default::default());
29
30 // Create the driver, from the HAL.
31 let driver = Driver::new(p.USB, Irqs);
32
33 // Create embassy-usb Config
34 let mut config = Config::new(0xc0de, 0xcafe);
35 config.manufacturer = Some("Embassy");
36 config.product = Some("USB-MIDI example");
37 config.serial_number = Some("12345678");
38 config.max_power = 100;
39 config.max_packet_size_0 = 64;
40
41 // Required for windows compatibility.
42 // https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.9.1/kconfig/CONFIG_CDC_ACM_IAD.html#help
43 config.device_class = 0xEF;
44 config.device_sub_class = 0x02;
45 config.device_protocol = 0x01;
46 config.composite_with_iads = true;
47
48 // Create embassy-usb DeviceBuilder using the driver and config.
49 // It needs some buffers for building the descriptors.
50 let mut device_descriptor = [0; 256];
51 let mut config_descriptor = [0; 256];
52 let mut bos_descriptor = [0; 256];
53 let mut control_buf = [0; 64];
54
55 let mut builder = Builder::new(
56 driver,
57 config,
58 &mut device_descriptor,
59 &mut config_descriptor,
60 &mut bos_descriptor,
61 &mut control_buf,
62 );
63
64 // Create classes on the builder.
65 let mut class = MidiClass::new(&mut builder, 1, 1, 64);
66
67 // The `MidiClass` can be split into `Sender` and `Receiver`, to be used in separate tasks.
68 // let (sender, receiver) = class.split();
69
70 // Build the builder.
71 let mut usb = builder.build();
72
73 // Run the USB device.
74 let usb_fut = usb.run();
75
76 // Use the Midi class!
77 let midi_fut = async {
78 loop {
79 class.wait_connection().await;
80 info!("Connected");
81 let _ = midi_echo(&mut class).await;
82 info!("Disconnected");
83 }
84 };
85
86 // Run everything concurrently.
87 // If we had made everything `'static` above instead, we could do this using separate tasks instead.
88 join(usb_fut, midi_fut).await;
89}
90
91struct Disconnected {}
92
93impl From<EndpointError> for Disconnected {
94 fn from(val: EndpointError) -> Self {
95 match val {
96 EndpointError::BufferOverflow => panic!("Buffer overflow"),
97 EndpointError::Disabled => Disconnected {},
98 }
99 }
100}
101
102async fn midi_echo<'d, T: Instance + 'd>(class: &mut MidiClass<'d, Driver<'d, T>>) -> Result<(), Disconnected> {
103 let mut buf = [0; 64];
104 loop {
105 let n = class.read_packet(&mut buf).await?;
106 let data = &buf[..n];
107 info!("data: {:x}", data);
108 class.write_packet(data).await?;
109 }
110}