usbMidiHost.ino

/*
 * usbMidiHost.ino
 *
 * This file includes the implementation for MIDI in/out
 * via the USB Host module using the "Revision 2.0 of MAX3421E-based USB Host Shield Library"
 *
 *  Created on: 18.05.2021
 *      Author: Marcel Licence
 *
 * You will require to use following library:
 * https://github.com/felis/USB_Host_Shield_2.0
 *
 * Please check out USB-MIDI dump utility from Yuuichi Akagawa
 */

#ifdef MIDI_VIA_USB_ENABLED
/*
 * Connections:
 *  CS: IO5
 *  INT: IO17 (not used)
 *  SCK: IO18
 *  MISO: IO19
 *  MOSI: IO23
 */

#include <usbh_midi.h>
#include <usbhub.h>
#include <SPI.h>

USB Usb;
USBH_MIDI  Midi(&Usb);

static void UsbMidi_Poll();

uint16_t pid, vid;

struct usbMidiMappingEntry_s
{
    void (*sendRaw)(uint8_t *buf);
    void (*shortMsg)(uint8_t *buf);
    void (*liveMsg)(uint8_t *buf);
    void (*sysEx)(uint8_t *buf, uint8_t len);

    uint8_t cableMask;
};

struct usbMidiMapping_s
{
    void (*usbMidiRxIndication)(uint8_t cable);
    void (*usbMidiTxIndication)(uint8_t cable);

    struct usbMidiMappingEntry_s *usbMidiMappingEntries;
    int usbMidiMappingEntriesCount;
};

extern struct usbMidiMapping_s usbMidiMapping; /* definition in z_config.ino */

void UsbMidi_Setup()
{
    vid = pid = 0;
    Serial.begin(115200);
    Serial.println("Hello now we can start\n");

    if (Usb.Init() == -1)
    {
        Serial.println("Usb init failed!\n");
        while (1); //halt
    }//if (Usb.Init() == -1...
    delay(200);
    Serial.println("Usb init done!\n");
}

uint8_t lastState = 0xFF;

void UsbMidi_Loop()
{
    Usb.Task();

    if (lastState != Usb.getUsbTaskState())
    {
        lastState = Usb.getUsbTaskState();
        Serial.printf("state: %d\n",  Usb.getUsbTaskState());
        switch (Usb.getUsbTaskState())
        {
        case USB_STATE_DETACHED:
            Serial.printf("    USB_STATE_DETACHED\n");
            vid = pid = 0;
            break;

        case USB_DETACHED_SUBSTATE_INITIALIZE:
            Serial.printf("    USB_DETACHED_SUBSTATE_INITIALIZE\n");
            vid = pid = 0;
            break;

        case USB_DETACHED_SUBSTATE_WAIT_FOR_DEVICE:
            Serial.printf("    USB_DETACHED_SUBSTATE_WAIT_FOR_DEVICE\n");
            vid = pid = 0;
            break;

        case USB_DETACHED_SUBSTATE_ILLEGAL:
            Serial.printf("    USB_DETACHED_SUBSTATE_ILLEGAL\n");
            vid = pid = 0;
            break;

        case USB_ATTACHED_SUBSTATE_SETTLE:
            Serial.printf("    USB_ATTACHED_SUBSTATE_SETTLE\n");
            break;

        case USB_ATTACHED_SUBSTATE_RESET_DEVICE:
            Serial.printf("    USB_ATTACHED_SUBSTATE_RESET_DEVICE\n");
            break;

        case USB_ATTACHED_SUBSTATE_WAIT_RESET_COMPLETE:
            Serial.printf("    USB_ATTACHED_SUBSTATE_WAIT_RESET_COMPLETE\n");
            break;

        case USB_ATTACHED_SUBSTATE_WAIT_SOF:
            Serial.printf("    USB_ATTACHED_SUBSTATE_WAIT_SOF\n");
            break;

        case USB_ATTACHED_SUBSTATE_WAIT_RESET:
            Serial.printf("    USB_ATTACHED_SUBSTATE_WAIT_RESET\n");
            break;

        case USB_ATTACHED_SUBSTATE_GET_DEVICE_DESCRIPTOR_SIZE:
            Serial.printf("    USB_ATTACHED_SUBSTATE_GET_DEVICE_DESCRIPTOR_SIZE\n");
            break;

        case USB_STATE_CONFIGURING:
            Serial.printf("    USB_STATE_CONFIGURING\n");
            break;

        case USB_STATE_RUNNING:
            Serial.printf("    USB_STATE_RUNNING\n");
            break;

        case USB_STATE_ERROR:
            Serial.printf("    USB_STATE_ERROR\n");
            break;

        }
    }
    if (Midi)
    {
        UsbMidi_Poll();
    }
}

uint8_t msgQueue[128][3];

uint8_t msgQueueIn = 0;
uint8_t msgQueueOut = 0;

inline
void UsbMidi_HandleSysEx(uint8_t *buf, uint8_t len)
{
    Serial.printf("not supported yet\n");
}

inline
void UsbMidi_HandleLiveMsg(uint8_t msg)
{
    //Serial.printf("live msg\n");
}

inline
void UsbMidi_HandleShortMsg(uint8_t *data)
{
    Serial.printf("short: %02x %02x %02x\n", data[0], data[1], data[2]);

    /* forward data to mapped function */
    for (int i = 0; i < usbMidiMapping.usbMidiMappingEntriesCount; i++)
    {
        if (((1 << 0) & usbMidiMapping.usbMidiMappingEntries[i].cableMask) > 0)
        {
            usbMidiMapping.usbMidiMappingEntries[i].shortMsg(data);
        }
    }
}

uint8_t MIDI_handleMsg(uint8_t *data, uint16_t len, uint8_t cable)
{
    /* sometimes we got just zeros from some hardware */
    int i = 0;
    while (data[i] == 0)
    {
        i++;
    }
    if (i > 0)
    {
        return i;
    }

    if ((data[0] & 0xF0) == 0xF0)
    {
        /* handle status msg */
        if (data[0] ==  0xF0)
        {
            for (int i = 2; i < len; i++)
            {
                if (data[i] == 0xF7)
                {
                    UsbMidi_HandleSysEx(data, i);
                    return i + 1;
                }
            }
        }
        else
        {
            UsbMidi_HandleLiveMsg(data[0]);
            return 1;
        }
    }
    else
    {
        memcpy(msgQueue[msgQueueIn], &data[0], 3);
        msgQueueIn++;
        if (msgQueueIn >= 128)
        {
            msgQueueIn = 0;
        }
        return 3;
    }

    Serial.printf("unhandled:\n");
    for (int i = 0; i < len; i++)
    {
        Serial.printf("0x%02x ", data[i]);
    }
    Serial.printf("\n");
}

/* process data now */
void UsbMidi_ProcessSync(void)
{
    while (msgQueueIn != msgQueueOut)
    {
        UsbMidi_HandleShortMsg(msgQueue[msgQueueOut]);
        msgQueueOut ++;
        if (msgQueueOut >= 128)
        {
            msgQueueOut = 0;
        }
    }
}

static void UsbMidi_Poll()
{
    uint8_t bufMidi[MIDI_EVENT_PACKET_SIZE];
    uint16_t  rcvd;

    memset(bufMidi, 0xCC, sizeof(bufMidi));

    if (Midi.idVendor() != vid || Midi.idProduct() != pid)
    {
        vid = Midi.idVendor();
        pid = Midi.idProduct();
        Serial.printf("VID: %04x, PID: %04x\n", vid, pid);
    }

    if (Midi.RecvData(&rcvd,  bufMidi) == 0)
    {
        if (rcvd == 0)
        {
            /* Some devices sending a lot of empty messages */
            return;
        }

        uint8_t *midiData = &bufMidi[0];
        while (rcvd > 2)
        {
            midiData = &midiData[1];
            int consumed = MIDI_handleMsg(midiData, rcvd, (bufMidi[0] >> 4) & 0xF);
            midiData = &midiData[consumed];
            if (consumed > rcvd)
            {
                Serial.printf("overrun!\n");
                return;
            }
            rcvd -= consumed;
        }
    }
}

void UsbMidi_SendRaw(uint8_t *buf, uint8_t cable)
{
    Midi.SendData(buf, cable);
}

inline
void UsbMidi_SendControlChange(uint8_t channel, uint8_t data1, uint8_t data2)
{
    uint8_t shortBuf[3] = {(uint8_t)(0xB0U + (channel & 0x0FU)), data1, data2};
    Serial2.write(shortBuf, 3);
}

#endif /* MIDI_VIA_USB_ENABLED */