tinyUSB/examples/host/hid_to_cdc/src/main.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.
 *
 */

// This example runs both host and device concurrently. The USB host looks for
// any HID device with reports that are 8 bytes long and then assumes they are
// keyboard reports. It translates the keypresses of the reports to ASCII and
// transmits it over CDC to the device's host.

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

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

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

// uncomment if you are using colemak layout
// #define KEYBOARD_COLEMAK

#ifdef KEYBOARD_COLEMAK
const uint8_t colemak[128] = {
  0  ,  0,  0,  0,  0,  0,  0, 22,
  9  , 23,  7,  0, 24, 17,  8, 12,
  0  , 14, 28, 51,  0, 19, 21, 10,
  15 ,  0,  0,  0, 13,  0,  0,  0,
  0  ,  0,  0,  0,  0,  0,  0,  0,
  0  ,  0,  0,  0,  0,  0,  0,  0,
  0  ,  0,  0, 18,  0,  0,  0,  0,
  0  ,  0,  0,  0,  0,  0,  0,  0,
  0  ,  0,  0,  0,  0,  0,  0,  0,
  0  ,  0,  0,  0,  0,  0,  0,  0
};
#endif

static uint8_t const keycode2ascii[128][2] =  { HID_KEYCODE_TO_ASCII };

/* 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 cdc_task(void);

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

  while (1)
  {
    tud_task(); // tinyusb device task
    tuh_task(); // tinyusb host task
    led_blinking_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;
}

//--------------------------------------------------------------------+
// Host callbacks
//--------------------------------------------------------------------+

// Invoked when device with hid interface is mounted
// Report descriptor is also available for use. tuh_hid_parse_report_descriptor()
// can be used to parse common/simple enough descriptor.
// Note: if report descriptor length > CFG_TUH_ENUMERATION_BUFSIZE, it will be skipped
// therefore report_desc = NULL, desc_len = 0
void tuh_hid_mount_cb(uint8_t dev_addr, uint8_t instance, uint8_t const* desc_report, uint16_t desc_len)
{
  (void)desc_report;
  (void)desc_len;
  uint16_t vid, pid;
  tuh_vid_pid_get(dev_addr, &vid, &pid);

  printf("HID device address = %d, instance = %d is mounted\r\n", dev_addr, instance);
  printf("VID = %04x, PID = %04x\r\n", vid, pid);

  // Receive any report and treat it like a keyboard.
  // tuh_hid_report_received_cb() will be invoked when report is available
  if ( !tuh_hid_receive_report(dev_addr, instance) )
  {
    printf("Error: cannot request to receive report\r\n");
  }
}

// Invoked when device with hid interface is un-mounted
void tuh_hid_umount_cb(uint8_t dev_addr, uint8_t instance)
{
  printf("HID device address = %d, instance = %d is unmounted\r\n", dev_addr, instance);
}

// keycodes from last report to check if key is holding or newly pressed
uint8_t last_keycodes[6] = {0};

// look up new key in previous keys
static inline bool key_in_last_report(const uint8_t key_arr[6], uint8_t keycode)
{
  for(uint8_t i=0; i<6; i++)
  {
    if (key_arr[i] == keycode) return true;
  }

  return false;
}

// Invoked when received report from device via interrupt endpoint
void tuh_hid_report_received_cb(uint8_t dev_addr, uint8_t instance, uint8_t const* report, uint16_t len)
{
  if (len != 8)
  {
    char ch_num;

    tud_cdc_write_str("incorrect report len: ");

    if ( len > 10 )
    {
      ch_num = '0' + (len / 10);
      tud_cdc_write(&ch_num, 1);
      len = len % 10;
    }

    ch_num = '0' + len;
    tud_cdc_write(&ch_num, 1);

    tud_cdc_write_str("\r\n");
    tud_cdc_write_flush();

    // Don't request a new report for a wrong sized endpoint.
    return;
  }

  uint8_t const modifiers = report[0];
  bool flush = false;

  for (int i = 2; i < 8; i++)
  {
    uint8_t keycode = report[i];

    if (keycode)
    {
      if ( key_in_last_report(last_keycodes, keycode) )
      {
        // exist in previous report means the current key is holding
        // do nothing
      }else
      {
        // not existed in previous report means the current key is pressed
        // Only print keycodes 0 - 128.
        if (keycode < 128)
        {
          // remap the key code for Colemak layout so @tannewt can type.
          #ifdef KEYBOARD_COLEMAK
          uint8_t colemak_key_code = colemak[keycode];
          if (colemak_key_code != 0) keycode = colemak_key_code;
          #endif

          bool const is_shift = modifiers & (KEYBOARD_MODIFIER_LEFTSHIFT | KEYBOARD_MODIFIER_RIGHTSHIFT);
          char c = keycode2ascii[keycode][is_shift ? 1 : 0];
          if (c)
          {
            if (c == '\n') tud_cdc_write("\r", 1);
            tud_cdc_write(&c, 1);
            flush = true;
          }
        }
      }
    }
  }

  if (flush) tud_cdc_write_flush();

  // save current report
  memcpy(last_keycodes, report+2, 6);

  // continue to request to receive report
  if ( !tuh_hid_receive_report(dev_addr, instance) )
  {
    printf("Error: cannot request to receive report\r\n");
  }
}



//--------------------------------------------------------------------+
// 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() )
    {
      // read datas
      char buf[64];
      uint32_t count = tud_cdc_read(buf, sizeof(buf));
      (void) count;

      // Echo back
      // Note: Skip echo by commenting out write() and write_flush()
      // for throughput test e.g
      //    $ dd if=/dev/zero of=/dev/ttyACM0 count=10000
      tud_cdc_write(buf, count);
      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;

  // TODO set some indicator
  if ( dtr )
  {
    // Terminal connected
  }else
  {
    // Terminal disconnected
  }
}

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

//--------------------------------------------------------------------+
// 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
}