stm32f4: usb_midi: Introduce example MIDI firmware
Tested on STM32F4Discovery with Linux host using both amidi (raw messages to/from device) and a synthesizer (note on/off) and on Windows 7 using MIDI-OX.
This commit is contained in:
Daniel Thompson
committed by
Karl Palsson
Karl Palsson
parent
766be687dc
commit
75389c665d
387
examples/stm32/f4/stm32f4-discovery/usb_midi/usbmidi.c
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387
examples/stm32/f4/stm32f4-discovery/usb_midi/usbmidi.c
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/*
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* This file is part of the libopencm3 project.
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*
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* Copyright (C) 2014 Daniel Thompson <daniel@redfelineninja.org.uk>
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*
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* This library is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdlib.h>
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#include <libopencm3/usb/usbd.h>
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#include <libopencm3/usb/audio.h>
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#include <libopencm3/usb/midi.h>
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#include <libopencm3/cm3/scb.h>
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#include <libopencm3/stm32/rcc.h>
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#include <libopencm3/stm32/gpio.h>
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/*
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* All references in this file come from Universal Serial Bus Device Class
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* Definition for MIDI Devices, release 1.0.
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*/
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/*
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* Table B-1: MIDI Adapter Device Descriptor
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*/
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static const struct usb_device_descriptor dev = {
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.bLength = USB_DT_DEVICE_SIZE,
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.bDescriptorType = USB_DT_DEVICE,
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.bcdUSB = 0x0200, /* was 0x0110 in Table B-1 example descriptor */
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.bDeviceClass = 0, /* device defined at interface level */
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.bDeviceSubClass = 0,
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.bDeviceProtocol = 0,
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.bMaxPacketSize0 = 64,
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.idVendor = 0x6666, /* Prototype product vendor ID */
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.idProduct = 0x5119, /* dd if=/dev/random bs=2 count=1 | hexdump */
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.bcdDevice = 0x0100,
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.iManufacturer = 1, /* index to string desc */
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.iProduct = 2, /* index to string desc */
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.iSerialNumber = 0,
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.bNumConfigurations = 1,
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};
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/*
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* Midi specific endpoint descriptors.
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*/
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static const struct usb_midi_endpoint_descriptor midi_bulk_endp[] = {{
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/* Table B-12: MIDI Adapter Class-specific Bulk OUT Endpoint
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* Descriptor
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*/
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.head = {
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.bLength = sizeof(struct usb_midi_endpoint_descriptor),
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.bDescriptorType = USB_AUDIO_DT_CS_ENDPOINT,
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.bDescriptorSubType = USB_MIDI_SUBTYPE_MS_GENERAL,
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.bNumEmbMIDIJack = 1,
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},
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.jack[0] = {
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.baAssocJackID = 0x01,
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},
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}, {
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/* Table B-14: MIDI Adapter Class-specific Bulk IN Endpoint
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* Descriptor
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*/
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.head = {
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.bLength = sizeof(struct usb_midi_endpoint_descriptor),
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.bDescriptorType = USB_AUDIO_DT_CS_ENDPOINT,
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.bDescriptorSubType = USB_MIDI_SUBTYPE_MS_GENERAL,
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.bNumEmbMIDIJack = 1,
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},
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.jack[0] = {
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.baAssocJackID = 0x03,
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},
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} };
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/*
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* Standard endpoint descriptors
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*/
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static const struct usb_endpoint_descriptor bulk_endp[] = {{
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/* Table B-11: MIDI Adapter Standard Bulk OUT Endpoint Descriptor */
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.bLength = USB_DT_ENDPOINT_SIZE,
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.bDescriptorType = USB_DT_ENDPOINT,
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.bEndpointAddress = 0x01,
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.bmAttributes = USB_ENDPOINT_ATTR_BULK,
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.wMaxPacketSize = 0x40,
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.bInterval = 0x00,
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.extra = &midi_bulk_endp[0],
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.extralen = sizeof(midi_bulk_endp[0])
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}, {
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.bLength = USB_DT_ENDPOINT_SIZE,
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.bDescriptorType = USB_DT_ENDPOINT,
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.bEndpointAddress = 0x81,
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.bmAttributes = USB_ENDPOINT_ATTR_BULK,
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.wMaxPacketSize = 0x40,
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.bInterval = 0x00,
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.extra = &midi_bulk_endp[1],
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.extralen = sizeof(midi_bulk_endp[1])
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} };
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/*
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* Table B-4: MIDI Adapter Class-specific AC Interface Descriptor
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*/
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static const struct {
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struct usb_audio_header_descriptor_head header_head;
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struct usb_audio_header_descriptor_body header_body;
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} __attribute__((packed)) audio_control_functional_descriptors = {
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.header_head = {
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.bLength = sizeof(struct usb_audio_header_descriptor_head) +
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1 * sizeof(struct usb_audio_header_descriptor_body),
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.bDescriptorType = USB_AUDIO_DT_CS_INTERFACE,
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.bDescriptorSubtype = USB_AUDIO_TYPE_HEADER,
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.bcdADC = 0x0100,
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.wTotalLength =
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sizeof(struct usb_audio_header_descriptor_head) +
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1 * sizeof(struct usb_audio_header_descriptor_body),
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.binCollection = 1,
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},
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.header_body = {
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.baInterfaceNr = 0x01,
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},
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};
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/*
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* Table B-3: MIDI Adapter Standard AC Interface Descriptor
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*/
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static const struct usb_interface_descriptor audio_control_iface[] = {{
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.bLength = USB_DT_INTERFACE_SIZE,
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.bDescriptorType = USB_DT_INTERFACE,
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.bInterfaceNumber = 0,
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.bAlternateSetting = 0,
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.bNumEndpoints = 0,
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.bInterfaceClass = USB_CLASS_AUDIO,
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.bInterfaceSubClass = USB_AUDIO_SUBCLASS_CONTROL,
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.bInterfaceProtocol = 0,
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.iInterface = 0,
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.extra = &audio_control_functional_descriptors,
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.extralen = sizeof(audio_control_functional_descriptors)
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} };
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/*
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* Class-specific MIDI streaming interface descriptor
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*/
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static const struct {
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struct usb_midi_header_descriptor header;
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struct usb_midi_in_jack_descriptor in_embedded;
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struct usb_midi_in_jack_descriptor in_external;
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struct usb_midi_out_jack_descriptor out_embedded;
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struct usb_midi_out_jack_descriptor out_external;
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} __attribute__((packed)) midi_streaming_functional_descriptors = {
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/* Table B-6: Midi Adapter Class-specific MS Interface Descriptor */
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.header = {
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.bLength = sizeof(struct usb_midi_header_descriptor),
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.bDescriptorType = USB_AUDIO_DT_CS_INTERFACE,
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.bDescriptorSubtype = USB_MIDI_SUBTYPE_MS_HEADER,
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.bcdMSC = 0x0100,
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.wTotalLength = sizeof(midi_streaming_functional_descriptors),
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},
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/* Table B-7: MIDI Adapter MIDI IN Jack Descriptor (Embedded) */
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.in_embedded = {
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.bLength = sizeof(struct usb_midi_in_jack_descriptor),
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.bDescriptorType = USB_AUDIO_DT_CS_INTERFACE,
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.bDescriptorSubtype = USB_MIDI_SUBTYPE_MIDI_IN_JACK,
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.bJackType = USB_MIDI_JACK_TYPE_EMBEDDED,
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.bJackID = 0x01,
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.iJack = 0x00,
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},
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/* Table B-8: MIDI Adapter MIDI IN Jack Descriptor (External) */
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.in_external = {
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.bLength = sizeof(struct usb_midi_in_jack_descriptor),
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.bDescriptorType = USB_AUDIO_DT_CS_INTERFACE,
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.bDescriptorSubtype = USB_MIDI_SUBTYPE_MIDI_IN_JACK,
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.bJackType = USB_MIDI_JACK_TYPE_EXTERNAL,
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.bJackID = 0x02,
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.iJack = 0x00,
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},
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/* Table B-9: MIDI Adapter MIDI OUT Jack Descriptor (Embedded) */
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.out_embedded = {
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.head = {
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.bLength = sizeof(struct usb_midi_out_jack_descriptor),
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.bDescriptorType = USB_AUDIO_DT_CS_INTERFACE,
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.bDescriptorSubtype = USB_MIDI_SUBTYPE_MIDI_OUT_JACK,
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.bJackType = USB_MIDI_JACK_TYPE_EMBEDDED,
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.bJackID = 0x03,
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.bNrInputPins = 1,
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},
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.source[0] = {
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.baSourceID = 0x02,
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.baSourcePin = 0x01,
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},
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.tail = {
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.iJack = 0x00,
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}
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},
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/* Table B-10: MIDI Adapter MIDI OUT Jack Descriptor (External) */
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.out_external = {
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.head = {
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.bLength = sizeof(struct usb_midi_out_jack_descriptor),
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.bDescriptorType = USB_AUDIO_DT_CS_INTERFACE,
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.bDescriptorSubtype = USB_MIDI_SUBTYPE_MIDI_OUT_JACK,
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.bJackType = USB_MIDI_JACK_TYPE_EXTERNAL,
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.bJackID = 0x04,
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.bNrInputPins = 1,
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},
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.source[0] = {
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.baSourceID = 0x01,
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.baSourcePin = 0x01,
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},
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.tail = {
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.iJack = 0x00,
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},
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},
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};
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/*
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* Table B-5: MIDI Adapter Standard MS Interface Descriptor
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*/
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static const struct usb_interface_descriptor midi_streaming_iface[] = {{
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.bLength = USB_DT_INTERFACE_SIZE,
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.bDescriptorType = USB_DT_INTERFACE,
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.bInterfaceNumber = 1,
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.bAlternateSetting = 0,
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.bNumEndpoints = 2,
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.bInterfaceClass = USB_CLASS_AUDIO,
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.bInterfaceSubClass = USB_AUDIO_SUBCLASS_MIDISTREAMING,
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.bInterfaceProtocol = 0,
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.iInterface = 0,
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.endpoint = bulk_endp,
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.extra = &midi_streaming_functional_descriptors,
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.extralen = sizeof(midi_streaming_functional_descriptors)
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} };
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static const struct usb_interface ifaces[] = {{
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.num_altsetting = 1,
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.altsetting = audio_control_iface,
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}, {
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.num_altsetting = 1,
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.altsetting = midi_streaming_iface,
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} };
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/*
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* Table B-2: MIDI Adapter Configuration Descriptor
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*/
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static const struct usb_config_descriptor config = {
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.bLength = USB_DT_CONFIGURATION_SIZE,
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.bDescriptorType = USB_DT_CONFIGURATION,
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.wTotalLength = 0, /* can be anything, it is updated automatically
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when the usb code prepares the descriptor */
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.bNumInterfaces = 2, /* control and data */
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.bConfigurationValue = 1,
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.iConfiguration = 0,
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.bmAttributes = 0x80, /* bus powered */
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.bMaxPower = 0x32,
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.interface = ifaces,
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};
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static const char * usb_strings[] = {
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"libopencm3.org",
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"MIDI demo",
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};
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/* Buffer to be used for control requests. */
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uint8_t usbd_control_buffer[128];
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/* SysEx identity message, preformatted with correct USB framing information */
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const uint8_t sysex_identity[] = {
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0x04, /* USB Framing (3 byte SysEx) */
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0xf0, /* SysEx start */
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0x7e, /* non-realtime */
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0x00, /* Channel 0 */
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0x04, /* USB Framing (3 byte SysEx) */
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0x7d, /* Educational/prototype manufacturer ID */
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0x66, /* Family code (byte 1) */
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0x66, /* Family code (byte 2) */
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0x04, /* USB Framing (3 byte SysEx) */
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0x51, /* Model number (byte 1) */
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0x19, /* Model number (byte 2) */
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0x00, /* Version number (byte 1) */
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0x04, /* USB Framing (3 byte SysEx) */
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0x00, /* Version number (byte 2) */
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0x01, /* Version number (byte 3) */
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0x00, /* Version number (byte 4) */
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0x05, /* USB Framing (1 byte SysEx) */
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0xf7, /* SysEx end */
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0x00, /* Padding */
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0x00, /* Padding */
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};
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static void usbmidi_data_rx_cb(usbd_device *usbd_dev, uint8_t ep)
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{
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(void)ep;
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char buf[64];
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int len = usbd_ep_read_packet(usbd_dev, 0x01, buf, 64);
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/* This implementation treats any message from the host as a SysEx
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* identity request. This works well enough providing the host
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* packs the identify request in a single 8 byte USB message.
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*/
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if (len) {
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while (usbd_ep_write_packet(usbd_dev, 0x81, sysex_identity,
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sizeof(sysex_identity)) == 0);
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}
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gpio_toggle(GPIOC, GPIO5);
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}
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static void usbmidi_set_config(usbd_device *usbd_dev, uint16_t wValue)
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{
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(void)wValue;
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usbd_ep_setup(usbd_dev, 0x01, USB_ENDPOINT_ATTR_BULK, 64,
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usbmidi_data_rx_cb);
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usbd_ep_setup(usbd_dev, 0x81, USB_ENDPOINT_ATTR_BULK, 64, NULL);
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}
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static void button_send_event(usbd_device *usbd_dev, int pressed)
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{
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char buf[4] = { 0x08, /* USB framing: virtual cable 0, note on */
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0x80, /* MIDI command: note on, channel 1 */
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60, /* Note 60 (middle C) */
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64, /* "Normal" velocity */
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};
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buf[0] |= pressed;
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buf[1] |= pressed << 4;
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while (usbd_ep_write_packet(usbd_dev, 0x81, buf, sizeof(buf)) == 0);
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}
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static void button_poll(usbd_device *usbd_dev)
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{
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static uint32_t button_state = 0;
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/* This is a simple shift based debounce. It's simplistic because
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* although this implements debounce adequately it does not have any
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* noise suppression. It is also very wide (32-bits) because it can
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* be polled in a very tight loop (no debounce timer).
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*/
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uint32_t old_button_state = button_state;
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button_state = (button_state << 1) | (GPIOA_IDR & 1);
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if ((0 == button_state) != (0 == old_button_state)) {
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button_send_event(usbd_dev, !!button_state);
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}
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}
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int main(void)
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{
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usbd_device *usbd_dev;
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rcc_clock_setup_hse_3v3(&hse_8mhz_3v3[CLOCK_3V3_120MHZ]);
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rcc_periph_clock_enable(RCC_GPIOA);
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rcc_periph_clock_enable(RCC_OTGFS);
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/* USB pins */
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gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE,
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GPIO9 | GPIO11 | GPIO12);
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gpio_set_af(GPIOA, GPIO_AF10, GPIO9 | GPIO11 | GPIO12);
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/* Button pin */
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gpio_mode_setup(GPIOA, GPIO_MODE_INPUT, GPIO_PUPD_NONE, GPIO0);
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usbd_dev = usbd_init(&otgfs_usb_driver, &dev, &config,
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usb_strings, 2,
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usbd_control_buffer, sizeof(usbd_control_buffer));
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usbd_register_set_config_callback(usbd_dev, usbmidi_set_config);
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while (1) {
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usbd_poll(usbd_dev);
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button_poll(usbd_dev);
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}
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}
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