tinyUSB/examples/device/cdc_dual_ports/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.
 *
 */

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

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

/* 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;

static void led_blinking_task(void);
static void cdc_task(void);

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

  // init device stack on configured roothub port
  tud_init(BOARD_TUD_RHPORT);

  if (board_init_after_tusb) {
    board_init_after_tusb();
  }

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

// echo to either Serial0 or Serial1
// with Serial0 as all lower case, Serial1 as all upper case
static void echo_serial_port(uint8_t itf, uint8_t buf[], uint32_t count) {
  uint8_t const case_diff = 'a' - 'A';

  for (uint32_t i = 0; i < count; i++) {
    if (itf == 0) {
      // echo back 1st port as lower case
      if (isupper(buf[i])) buf[i] += case_diff;
    } else {
      // echo back 2nd port as upper case
      if (islower(buf[i])) buf[i] -= case_diff;
    }

    tud_cdc_n_write_char(itf, buf[i]);
  }
  tud_cdc_n_write_flush(itf);
}

// 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;
}


//--------------------------------------------------------------------+
// USB CDC
//--------------------------------------------------------------------+
static void cdc_task(void) {
  uint8_t itf;

  for (itf = 0; itf < CFG_TUD_CDC; itf++) {
    // connected() check for DTR bit
    // Most but not all terminal client set this when making connection
    // if ( tud_cdc_n_connected(itf) )
    {
      if (tud_cdc_n_available(itf)) {
        uint8_t buf[64];

        uint32_t count = tud_cdc_n_read(itf, buf, sizeof(buf));

        // echo back to both serial ports
        echo_serial_port(0, buf, count);
        echo_serial_port(1, buf, count);
      }
    }
  }
}

// Invoked when cdc when line state changed e.g connected/disconnected
// Use to reset to DFU when disconnect with 1200 bps
void tud_cdc_line_state_cb(uint8_t instance, bool dtr, bool rts) {
  (void)rts;

  // DTR = false is counted as disconnected
  if (!dtr) {
    // touch1200 only with first CDC instance (Serial)
    if (instance == 0) {
      cdc_line_coding_t coding;
      tud_cdc_get_line_coding(&coding);
      if (coding.bit_rate == 1200) {
        if (board_reset_to_bootloader) {
          board_reset_to_bootloader();
        }
      }
    }
  }
}

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