pico-serial-to-hid.c

/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2019 Ha Thach (tinyusb.org)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "bsp/board.h"
#include "tusb.h"

#include "usb_descriptors.h"

//--------------------------------------------------------------------+
// MACRO CONSTANT TYPEDEF PROTYPES
//--------------------------------------------------------------------+

/* Blink pattern
 * - 250 ms  : device not mounted
 * - 1000 ms : device mounted
 * - 2500 ms : device is suspended
 */
enum {
    BLINK_NOT_MOUNTED = 250,
    BLINK_MOUNTED = 1000,
    BLINK_SUSPENDED = 2500,
};

static uint32_t blink_interval_ms = BLINK_NOT_MOUNTED;

void led_blinking_task(void);
void hid_task(void);
void cdc_task(void);

/*------------- MAIN -------------*/
int main(void) {
    board_init();
    tusb_init();

    while (1) {
        tud_task(); // tinyusb device task
        led_blinking_task();

        hid_task();
        cdc_task();
    }

    return 0;
}

//--------------------------------------------------------------------+
// Device callbacks
//--------------------------------------------------------------------+

// Invoked when device is mounted
void tud_mount_cb(void) {
    blink_interval_ms = BLINK_MOUNTED;
}

// Invoked when device is unmounted
void tud_umount_cb(void) {
    blink_interval_ms = BLINK_NOT_MOUNTED;
}

// Invoked when usb bus is suspended
// remote_wakeup_en : if host allow us  to perform remote wakeup
// Within 7ms, device must draw an average of current less than 2.5 mA from bus
void tud_suspend_cb(bool remote_wakeup_en) {
    (void) remote_wakeup_en;
    blink_interval_ms = BLINK_SUSPENDED;
}

// Invoked when usb bus is resumed
void tud_resume_cb(void) {
    blink_interval_ms = BLINK_MOUNTED;
}


//--------------------------------------------------------------------+
// USB CDC
//--------------------------------------------------------------------+
void cdc_task(void)
{
    // connected() check for DTR bit
    // Most but not all terminal client set this when making connection
    // if ( tud_cdc_connected() )
    {
        // connected and there are data available
        if ( tud_cdc_available() )
        {
            uint8_t buf[64];

            // read and echo back
            uint32_t count = tud_cdc_read(buf, sizeof(buf));

            for(uint32_t i=0; i<count; i++)
            {
                tud_cdc_write_char(buf[i]);

                if ( buf[i] == '\r' ) tud_cdc_write_char('\n');
            }

            tud_cdc_write_flush();
        }
    }
}

// Invoked when cdc when line state changed e.g connected/disconnected
void tud_cdc_line_state_cb(uint8_t itf, bool dtr, bool rts)
{
    (void) itf;
    (void) rts;

    // connected
    if ( dtr )
    {
        // print initial message when connected
        tud_cdc_write_str("\r\nTinyUSB CDC MSC device example\r\n");
        tud_cdc_write_flush();
    }
}

// Invoked when CDC interface received data from host
void tud_cdc_rx_cb(uint8_t itf)
{
    (void) itf;
}

//--------------------------------------------------------------------+
// USB HID
//--------------------------------------------------------------------+

void hid_task(void) {
    // Poll every 10ms
    const uint32_t interval_ms = 10;
    static uint32_t start_ms = 0;

    if (board_millis() - start_ms < interval_ms) return; // not enough time
    start_ms += interval_ms;

    uint32_t const btn = 1;

    // Remote wakeup
    if (tud_suspended() && btn) {
        // Wake up host if we are in suspend mode
        // and REMOTE_WAKEUP feature is enabled by host
        tud_remote_wakeup();
    }

    /*------------- Mouse -------------*/
    if (tud_hid_ready()) {
        if (btn) {
            int8_t const delta = 5;

            // no button, right + down, no scroll pan
            tud_hid_mouse_report(REPORT_ID_MOUSE, 0x00, delta, delta, 0, 0);

            // delay a bit before attempt to send keyboard report
            board_delay(10);
        }
    }

    /*------------- Keyboard -------------*/
    if (tud_hid_ready()) {
        // use to avoid send multiple consecutive zero report for keyboard
        static bool has_key = false;

        static bool toggle = false;
        if (toggle = !toggle) {
            uint8_t keycode[6] = {0};
            keycode[0] = HID_KEY_A;

            tud_hid_keyboard_report(REPORT_ID_KEYBOARD, 0, keycode);

            has_key = true;
        } else {
            // send empty key report if previously has key pressed
            if (has_key) tud_hid_keyboard_report(REPORT_ID_KEYBOARD, 0, NULL);
            has_key = false;
        }
    }
}


// Invoked when received GET_REPORT control request
// Application must fill buffer report's content and return its length.
// Return zero will cause the stack to STALL request
uint16_t tud_hid_get_report_cb(uint8_t report_id, hid_report_type_t report_type, uint8_t *buffer, uint16_t reqlen) {
    // TODO not Implemented
    (void) report_id;
    (void) report_type;
    (void) buffer;
    (void) reqlen;

    return 0;
}

// Invoked when received SET_REPORT control request or
// received data on OUT endpoint ( Report ID = 0, Type = 0 )
void tud_hid_set_report_cb(uint8_t report_id, hid_report_type_t report_type, uint8_t const *buffer, uint16_t bufsize) {
    // TODO set LED based on CAPLOCK, NUMLOCK etc...
    (void) report_id;
    (void) report_type;
    (void) buffer;
    (void) bufsize;
}

//--------------------------------------------------------------------+
// BLINKING TASK
//--------------------------------------------------------------------+
void led_blinking_task(void) {
    static uint32_t start_ms = 0;
    static bool led_state = false;

    // Blink every interval ms
    if (board_millis() - start_ms < blink_interval_ms) return; // not enough time
    start_ms += blink_interval_ms;

    board_led_write(led_state);
    led_state = 1 - led_state; // toggle
}