aboutsummaryrefslogtreecommitdiffstats
path: root/demos/ARMCM4-STM32F407-LWIP-FATFS-USB/main.c
blob: 09a6ae3a60ead86e7ad8b1d7c67115eaa7f62b77 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
/*
    ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
                 2011,2012 Giovanni Di Sirio.

    This file is part of ChibiOS/RT.

    ChibiOS/RT is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    ChibiOS/RT is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

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

#include "ch.h"
#include "hal.h"
#include "test.h"

#include "usb_cdc.h"
#include "chprintf.h"
#include "shell.h"

#include "lwipthread.h"
#include "web/web.h"

#include "ff.h"

/*===========================================================================*/
/* Card insertion monitor.                                                   */
/*===========================================================================*/

#define POLLING_INTERVAL                10
#define POLLING_DELAY                   10

/**
 * @brief   Card monitor timer.
 */
static VirtualTimer tmr;

/**
 * @brief   Debounce counter.
 */
static unsigned cnt;

/**
 * @brief   Card event sources.
 */
static EventSource inserted_event, removed_event;

/**
 * @brief   Insertion monitor timer callback function.
 *
 * @param[in] p         pointer to the @p BaseBlockDevice object
 *
 * @notapi
 */
static void tmrfunc(void *p) {
  BaseBlockDevice *bbdp = p;

  chSysLockFromIsr();
  if (cnt > 0) {
    if (blkIsInserted(bbdp)) {
      if (--cnt == 0) {
        chEvtBroadcastI(&inserted_event);
      }
    }
    else
      cnt = POLLING_INTERVAL;
  }
  else {
    if (!blkIsInserted(bbdp)) {
      cnt = POLLING_INTERVAL;
      chEvtBroadcastI(&removed_event);
    }
  }
  chVTSetI(&tmr, MS2ST(POLLING_DELAY), tmrfunc, bbdp);
  chSysUnlockFromIsr();
}

/**
 * @brief   Polling monitor start.
 *
 * @param[in] p         pointer to an object implementing @p BaseBlockDevice
 *
 * @notapi
 */
static void tmr_init(void *p) {

  chEvtInit(&inserted_event);
  chEvtInit(&removed_event);
  chSysLock();
  cnt = POLLING_INTERVAL;
  chVTSetI(&tmr, MS2ST(POLLING_DELAY), tmrfunc, p);
  chSysUnlock();
}

/*===========================================================================*/
/* FatFs related.                                                            */
/*===========================================================================*/

/**
 * @brief FS object.
 */
static FATFS SDC_FS;

/* FS mounted and ready.*/
static bool_t fs_ready = FALSE;

/* Generic large buffer.*/
static uint8_t fbuff[1024];

static FRESULT scan_files(BaseSequentialStream *chp, char *path) {
  FRESULT res;
  FILINFO fno;
  DIR dir;
  int i;
  char *fn;

#if _USE_LFN
  fno.lfname = 0;
  fno.lfsize = 0;
#endif
  res = f_opendir(&dir, path);
  if (res == FR_OK) {
    i = strlen(path);
    for (;;) {
      res = f_readdir(&dir, &fno);
      if (res != FR_OK || fno.fname[0] == 0)
        break;
      if (fno.fname[0] == '.')
        continue;
      fn = fno.fname;
      if (fno.fattrib & AM_DIR) {
        path[i++] = '/';
        strcpy(&path[i], fn);
        res = scan_files(chp, path);
        if (res != FR_OK)
          break;
        path[--i] = 0;
      }
      else {
        chprintf(chp, "%s/%s\r\n", path, fn);
      }
    }
  }
  return res;
}

/*===========================================================================*/
/* USB related stuff.                                                        */
/*===========================================================================*/

/*
 * Serial over USB Driver structure.
 */
static SerialUSBDriver SDU1;

/*
 * USB Device Descriptor.
 */
static const uint8_t vcom_device_descriptor_data[18] = {
  USB_DESC_DEVICE       (0x0110,        /* bcdUSB (1.1).                    */
                         0x02,          /* bDeviceClass (CDC).              */
                         0x00,          /* bDeviceSubClass.                 */
                         0x00,          /* bDeviceProtocol.                 */
                         0x40,          /* bMaxPacketSize.                  */
                         0x0483,        /* idVendor (ST).                   */
                         0x5740,        /* idProduct.                       */
                         0x0200,        /* bcdDevice.                       */
                         1,             /* iManufacturer.                   */
                         2,             /* iProduct.                        */
                         3,             /* iSerialNumber.                   */
                         1)             /* bNumConfigurations.              */
};

/*
 * Device Descriptor wrapper.
 */
static const USBDescriptor vcom_device_descriptor = {
  sizeof vcom_device_descriptor_data,
  vcom_device_descriptor_data
};

/* Configuration Descriptor tree for a CDC.*/
static const uint8_t vcom_configuration_descriptor_data[67] = {
  /* Configuration Descriptor.*/
  USB_DESC_CONFIGURATION(67,            /* wTotalLength.                    */
                         0x02,          /* bNumInterfaces.                  */
                         0x01,          /* bConfigurationValue.             */
                         0,             /* iConfiguration.                  */
                         0xC0,          /* bmAttributes (self powered).     */
                         50),           /* bMaxPower (100mA).               */
  /* Interface Descriptor.*/
  USB_DESC_INTERFACE    (0x00,          /* bInterfaceNumber.                */
                         0x00,          /* bAlternateSetting.               */
                         0x01,          /* bNumEndpoints.                   */
                         0x02,          /* bInterfaceClass (Communications
                                           Interface Class, CDC section
                                           4.2).                            */
                         0x02,          /* bInterfaceSubClass (Abstract
                                         Control Model, CDC section 4.3).   */
                         0x01,          /* bInterfaceProtocol (AT commands,
                                           CDC section 4.4).                */
                         0),            /* iInterface.                      */
  /* Header Functional Descriptor (CDC section 5.2.3).*/
  USB_DESC_BYTE         (5),            /* bLength.                         */
  USB_DESC_BYTE         (0x24),         /* bDescriptorType (CS_INTERFACE).  */
  USB_DESC_BYTE         (0x00),         /* bDescriptorSubtype (Header
                                           Functional Descriptor.           */
  USB_DESC_BCD          (0x0110),       /* bcdCDC.                          */
  /* Call Management Functional Descriptor. */
  USB_DESC_BYTE         (5),            /* bFunctionLength.                 */
  USB_DESC_BYTE         (0x24),         /* bDescriptorType (CS_INTERFACE).  */
  USB_DESC_BYTE         (0x01),         /* bDescriptorSubtype (Call Management
                                           Functional Descriptor).          */
  USB_DESC_BYTE         (0x00),         /* bmCapabilities (D0+D1).          */
  USB_DESC_BYTE         (0x01),         /* bDataInterface.                  */
  /* ACM Functional Descriptor.*/
  USB_DESC_BYTE         (4),            /* bFunctionLength.                 */
  USB_DESC_BYTE         (0x24),         /* bDescriptorType (CS_INTERFACE).  */
  USB_DESC_BYTE         (0x02),         /* bDescriptorSubtype (Abstract
                                           Control Management Descriptor).  */
  USB_DESC_BYTE         (0x02),         /* bmCapabilities.                  */
  /* Union Functional Descriptor.*/
  USB_DESC_BYTE         (5),            /* bFunctionLength.                 */
  USB_DESC_BYTE         (0x24),         /* bDescriptorType (CS_INTERFACE).  */
  USB_DESC_BYTE         (0x06),         /* bDescriptorSubtype (Union
                                           Functional Descriptor).          */
  USB_DESC_BYTE         (0x00),         /* bMasterInterface (Communication
                                           Class Interface).                */
  USB_DESC_BYTE         (0x01),         /* bSlaveInterface0 (Data Class
                                           Interface).                      */
  /* Endpoint 2 Descriptor.*/
  USB_DESC_ENDPOINT     (USB_CDC_INTERRUPT_REQUEST_EP|0x80,
                         0x03,          /* bmAttributes (Interrupt).        */
                         0x0008,        /* wMaxPacketSize.                  */
                         0xFF),         /* bInterval.                       */
  /* Interface Descriptor.*/
  USB_DESC_INTERFACE    (0x01,          /* bInterfaceNumber.                */
                         0x00,          /* bAlternateSetting.               */
                         0x02,          /* bNumEndpoints.                   */
                         0x0A,          /* bInterfaceClass (Data Class
                                           Interface, CDC section 4.5).     */
                         0x00,          /* bInterfaceSubClass (CDC section
                                           4.6).                            */
                         0x00,          /* bInterfaceProtocol (CDC section
                                           4.7).                            */
                         0x00),         /* iInterface.                      */
  /* Endpoint 3 Descriptor.*/
  USB_DESC_ENDPOINT     (USB_CDC_DATA_AVAILABLE_EP,     /* bEndpointAddress.*/
                         0x02,          /* bmAttributes (Bulk).             */
                         0x0040,        /* wMaxPacketSize.                  */
                         0x00),         /* bInterval.                       */
  /* Endpoint 1 Descriptor.*/
  USB_DESC_ENDPOINT     (USB_CDC_DATA_REQUEST_EP|0x80,  /* bEndpointAddress.*/
                         0x02,          /* bmAttributes (Bulk).             */
                         0x0040,        /* wMaxPacketSize.                  */
                         0x00)          /* bInterval.                       */
};

/*
 * Configuration Descriptor wrapper.
 */
static const USBDescriptor vcom_configuration_descriptor = {
  sizeof vcom_configuration_descriptor_data,
  vcom_configuration_descriptor_data
};

/*
 * U.S. English language identifier.
 */
static const uint8_t vcom_string0[] = {
  USB_DESC_BYTE(4),                     /* bLength.                         */
  USB_DESC_BYTE(USB_DESCRIPTOR_STRING), /* bDescriptorType.                 */
  USB_DESC_WORD(0x0409)                 /* wLANGID (U.S. English).          */
};

/*
 * Vendor string.
 */
static const uint8_t vcom_string1[] = {
  USB_DESC_BYTE(38),                    /* bLength.                         */
  USB_DESC_BYTE(USB_DESCRIPTOR_STRING), /* bDescriptorType.                 */
  'S', 0, 'T', 0, 'M', 0, 'i', 0, 'c', 0, 'r', 0, 'o', 0, 'e', 0,
  'l', 0, 'e', 0, 'c', 0, 't', 0, 'r', 0, 'o', 0, 'n', 0, 'i', 0,
  'c', 0, 's', 0
};

/*
 * Device Description string.
 */
static const uint8_t vcom_string2[] = {
  USB_DESC_BYTE(56),                    /* bLength.                         */
  USB_DESC_BYTE(USB_DESCRIPTOR_STRING), /* bDescriptorType.                 */
  'C', 0, 'h', 0, 'i', 0, 'b', 0, 'i', 0, 'O', 0, 'S', 0, '/', 0,
  'R', 0, 'T', 0, ' ', 0, 'V', 0, 'i', 0, 'r', 0, 't', 0, 'u', 0,
  'a', 0, 'l', 0, ' ', 0, 'C', 0, 'O', 0, 'M', 0, ' ', 0, 'P', 0,
  'o', 0, 'r', 0, 't', 0
};

/*
 * Serial Number string.
 */
static const uint8_t vcom_string3[] = {
  USB_DESC_BYTE(8),                     /* bLength.                         */
  USB_DESC_BYTE(USB_DESCRIPTOR_STRING), /* bDescriptorType.                 */
  '0' + CH_KERNEL_MAJOR, 0,
  '0' + CH_KERNEL_MINOR, 0,
  '0' + CH_KERNEL_PATCH, 0
};

/*
 * Strings wrappers array.
 */
static const USBDescriptor vcom_strings[] = {
  {sizeof vcom_string0, vcom_string0},
  {sizeof vcom_string1, vcom_string1},
  {sizeof vcom_string2, vcom_string2},
  {sizeof vcom_string3, vcom_string3}
};

/*
 * Handles the GET_DESCRIPTOR callback. All required descriptors must be
 * handled here.
 */
static const USBDescriptor *get_descriptor(USBDriver *usbp,
                                           uint8_t dtype,
                                           uint8_t dindex,
                                           uint16_t lang) {

  (void)usbp;
  (void)lang;
  switch (dtype) {
  case USB_DESCRIPTOR_DEVICE:
    return &vcom_device_descriptor;
  case USB_DESCRIPTOR_CONFIGURATION:
    return &vcom_configuration_descriptor;
  case USB_DESCRIPTOR_STRING:
    if (dindex < 4)
      return &vcom_strings[dindex];
  }
  return NULL;
}

/**
 * @brief   IN EP1 state.
 */
static USBInEndpointState ep1instate;

/**
 * @brief   OUT EP1 state.
 */
static USBOutEndpointState ep1outstate;

/**
 * @brief   EP1 initialization structure (both IN and OUT).
 */
static const USBEndpointConfig ep1config = {
  USB_EP_MODE_TYPE_BULK,
  NULL,
  sduDataTransmitted,
  sduDataReceived,
  0x0040,
  0x0040,
  &ep1instate,
  &ep1outstate,
  2,
  NULL
};

/**
 * @brief   IN EP2 state.
 */
static USBInEndpointState ep2instate;

/**
 * @brief   EP2 initialization structure (IN only).
 */
static const USBEndpointConfig ep2config = {
  USB_EP_MODE_TYPE_INTR,
  NULL,
  sduInterruptTransmitted,
  NULL,
  0x0010,
  0x0000,
  &ep2instate,
  NULL,
  1,
  NULL
};

/*
 * Handles the USB driver global events.
 */
static void usb_event(USBDriver *usbp, usbevent_t event) {

  switch (event) {
  case USB_EVENT_RESET:
    return;
  case USB_EVENT_ADDRESS:
    return;
  case USB_EVENT_CONFIGURED:
    chSysLockFromIsr();

    /* Enables the endpoints specified into the configuration.
       Note, this callback is invoked from an ISR so I-Class functions
       must be used.*/
    usbInitEndpointI(usbp, USB_CDC_DATA_REQUEST_EP, &ep1config);
    usbInitEndpointI(usbp, USB_CDC_INTERRUPT_REQUEST_EP, &ep2config);

    /* Resetting the state of the CDC subsystem.*/
    sduConfigureHookI(usbp);

    chSysUnlockFromIsr();
    return;
  case USB_EVENT_SUSPEND:
    return;
  case USB_EVENT_WAKEUP:
    return;
  case USB_EVENT_STALLED:
    return;
  }
  return;
}

/*
 * USB driver configuration.
 */
static const USBConfig usbcfg = {
  usb_event,
  get_descriptor,
  sduRequestsHook,
  NULL
};

/*
 * Serial over USB driver configuration.
 */
static const SerialUSBConfig serusbcfg = {
  &USBD1
};

/*===========================================================================*/
/* Command line related.                                                     */
/*===========================================================================*/

#define SHELL_WA_SIZE   THD_WA_SIZE(2048)
#define TEST_WA_SIZE    THD_WA_SIZE(256)

static void cmd_mem(BaseSequentialStream *chp, int argc, char *argv[]) {
  size_t n, size;

  (void)argv;
  if (argc > 0) {
    chprintf(chp, "Usage: mem\r\n");
    return;
  }
  n = chHeapStatus(NULL, &size);
  chprintf(chp, "core free memory : %u bytes\r\n", chCoreStatus());
  chprintf(chp, "heap fragments   : %u\r\n", n);
  chprintf(chp, "heap free total  : %u bytes\r\n", size);
}

static void cmd_threads(BaseSequentialStream *chp, int argc, char *argv[]) {
  static const char *states[] = {THD_STATE_NAMES};
  Thread *tp;

  (void)argv;
  if (argc > 0) {
    chprintf(chp, "Usage: threads\r\n");
    return;
  }
  chprintf(chp, "    addr    stack prio refs     state time\r\n");
  tp = chRegFirstThread();
  do {
    chprintf(chp, "%.8lx %.8lx %4lu %4lu %9s %lu\r\n",
            (uint32_t)tp, (uint32_t)tp->p_ctx.r13,
            (uint32_t)tp->p_prio, (uint32_t)(tp->p_refs - 1),
            states[tp->p_state], (uint32_t)tp->p_time);
    tp = chRegNextThread(tp);
  } while (tp != NULL);
}

static void cmd_test(BaseSequentialStream *chp, int argc, char *argv[]) {
  Thread *tp;

  (void)argv;
  if (argc > 0) {
    chprintf(chp, "Usage: test\r\n");
    return;
  }
  tp = chThdCreateFromHeap(NULL, TEST_WA_SIZE, chThdGetPriority(),
                           TestThread, chp);
  if (tp == NULL) {
    chprintf(chp, "out of memory\r\n");
    return;
  }
  chThdWait(tp);
}

static void cmd_tree(BaseSequentialStream *chp, int argc, char *argv[]) {
  FRESULT err;
  uint32_t clusters;
  FATFS *fsp;

  (void)argv;
  if (argc > 0) {
    chprintf(chp, "Usage: tree\r\n");
    return;
  }
  if (!fs_ready) {
    chprintf(chp, "File System not mounted\r\n");
    return;
  }
  err = f_getfree("/", &clusters, &fsp);
  if (err != FR_OK) {
    chprintf(chp, "FS: f_getfree() failed\r\n");
    return;
  }
  chprintf(chp,
           "FS: %lu free clusters, %lu sectors per cluster, %lu bytes free\r\n",
           clusters, (uint32_t)SDC_FS.csize,
           clusters * (uint32_t)SDC_FS.csize * (uint32_t)MMCSD_BLOCK_SIZE);
  fbuff[0] = 0;
  scan_files(chp, (char *)fbuff);
}

static const ShellCommand commands[] = {
  {"mem", cmd_mem},
  {"threads", cmd_threads},
  {"test", cmd_test},
  {"tree", cmd_tree},
  {NULL, NULL}
};

static const ShellConfig shell_cfg1 = {
  (BaseSequentialStream *)&SDU1,
  commands
};

/*===========================================================================*/
/* Main and generic code.                                                    */
/*===========================================================================*/

/*
 * Card insertion event.
 */
static void InsertHandler(eventid_t id) {
  FRESULT err;

  (void)id;
  /*
   * On insertion SDC initialization and FS mount.
   */
  if (sdcConnect(&SDCD1))
    return;

  err = f_mount(0, &SDC_FS);
  if (err != FR_OK) {
    sdcDisconnect(&SDCD1);
    return;
  }
  fs_ready = TRUE;
}

/*
 * Card removal event.
 */
static void RemoveHandler(eventid_t id) {

  (void)id;
  sdcDisconnect(&SDCD1);
  fs_ready = FALSE;
}

/*
 * Green LED blinker thread, times are in milliseconds.
 */
static WORKING_AREA(waThread1, 128);
static msg_t Thread1(void *arg) {

  (void)arg;
  chRegSetThreadName("blinker");
  while (TRUE) {
    palTogglePad(GPIOC, GPIOC_LED);
    chThdSleepMilliseconds(fs_ready ? 125 : 500);
  }
}

/*
 * Application entry point.
 */
int main(void) {
  static Thread *shelltp = NULL;
  static const evhandler_t evhndl[] = {
    InsertHandler,
    RemoveHandler
  };
  struct EventListener el0, el1;

  /*
   * System initializations.
   * - HAL initialization, this also initializes the configured device drivers
   *   and performs the board-specific initializations.
   * - Kernel initialization, the main() function becomes a thread and the
   *   RTOS is active.
   */
  halInit();
  chSysInit();

  /*
   * Initializes a serial-over-USB CDC driver.
   */
  sduObjectInit(&SDU1);
  sduStart(&SDU1, &serusbcfg);

  /*
   * Activates the USB driver and then the USB bus pull-up on D+.
   * Note, a delay is inserted in order to not have to disconnect the cable
   * after a reset.
   */
  usbDisconnectBus(serusbcfg.usbp);
  chThdSleepMilliseconds(1000);
  usbStart(serusbcfg.usbp, &usbcfg);
  usbConnectBus(serusbcfg.usbp);

  /*
   * Shell manager initialization.
   */
  shellInit();

  /*
   * Activates the serial driver 6 and SDC driver 1 using default
   * configuration.
   */
  sdStart(&SD6, NULL);
  sdcStart(&SDCD1, NULL);

  /*
   * Activates the card insertion monitor.
   */
  tmr_init(&SDCD1);

  /*
   * Creates the blinker thread.
   */
  chThdCreateStatic(waThread1, sizeof(waThread1), NORMALPRIO, Thread1, NULL);

  /*
   * Creates the LWIP threads (it changes priority internally).
   */
  chThdCreateStatic(wa_lwip_thread, LWIP_THREAD_STACK_SIZE, NORMALPRIO + 2,
                    lwip_thread, NULL);

  /*
   * Creates the HTTP thread (it changes priority internally).
   */
  chThdCreateStatic(wa_http_server, sizeof(wa_http_server), NORMALPRIO + 1,
                    http_server, NULL);

  /*
   * Normal main() thread activity, in this demo it does nothing except
   * sleeping in a loop and listen for events.
   */
  chEvtRegister(&inserted_event, &el0, 0);
  chEvtRegister(&removed_event, &el1, 1);
  while (TRUE) {
    if (!shelltp && (SDU1.config->usbp->state == USB_ACTIVE))
      shelltp = shellCreate(&shell_cfg1, SHELL_WA_SIZE, NORMALPRIO);
    else if (chThdTerminated(shelltp)) {
      chThdRelease(shelltp);    /* Recovers memory of the previous shell.   */
      shelltp = NULL;           /* Triggers spawning of a new shell.        */
    }
    if (palReadPad(GPIOA, GPIOA_BUTTON_WKUP) != 0) {
    }
    chEvtDispatch(evhndl, chEvtWaitOneTimeout(ALL_EVENTS, MS2ST(500)));
  }
}