~technomancy/menelaus

menelaus/usb_keyboard.c -rw-r--r-- 19.0 KiB
71e98173Phil Hagelberg Fix reset function. 8 months ago
                                                                                
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
/* USB Keyboard Example for Teensy USB Development Board
 * http://www.pjrc.com/teensy/usb_keyboard.html
 * Copyright (c) 2009 PJRC.COM, LLC
 *
 * 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.
 */

// Version 1.0: Initial Release
// Version 1.1: Add support for Teensy 2.0

#define USB_SERIAL_PRIVATE_INCLUDE
#include "usb_keyboard.h"
#include <util/delay.h>

/**************************************************************************
 *
 *  Configurable Options
 *
 **************************************************************************/

// You can change these to give your code its own name.
#define STR_MANUFACTURER    L"Technomancy"
#define STR_PRODUCT         L"Atreus"


// Mac OS-X and Linux automatically load the correct drivers.  On
// Windows, even though the driver is supplied by Microsoft, an
// INF file is needed to load the driver.  These numbers need to
// match the INF file.
#define VENDOR_ID       0x16C0
#define PRODUCT_ID      0x047C


// USB devices are supposed to implment a halt feature, which is
// rarely (if ever) used.  If you comment this line out, the halt
// code will be removed, saving 102 bytes of space (gcc 4.3.0).
// This is not strictly USB compliant, but works with all major
// operating systems.
#define SUPPORT_ENDPOINT_HALT



/**************************************************************************
 *
 *  Endpoint Buffer Configuration
 *
 **************************************************************************/

#define ENDPOINT0_SIZE      32

#define KEYBOARD_INTERFACE  0
#define KEYBOARD_ENDPOINT   3
#define KEYBOARD_SIZE       8
#define KEYBOARD_BUFFER     EP_DOUBLE_BUFFER

static const uint8_t PROGMEM endpoint_config_table[] = {
  0,
  0,
  1, EP_TYPE_INTERRUPT_IN,  EP_SIZE(KEYBOARD_SIZE) | KEYBOARD_BUFFER,
  0
};


/**************************************************************************
 *
 *  Descriptor Data
 *
 **************************************************************************/

// Descriptors are the data that your computer reads when it auto-detects
// this USB device (called "enumeration" in USB lingo).  The most commonly
// changed items are editable at the top of this file.  Changing things
// in here should only be done by those who've read chapter 9 of the USB
// spec and relevant portions of any USB class specifications!


static uint8_t const PROGMEM device_descriptor[] = {
  18,                 // bLength
  1,                  // bDescriptorType
  0x00, 0x02,             // bcdUSB
  0,                  // bDeviceClass
  0,                  // bDeviceSubClass
  0,                  // bDeviceProtocol
  ENDPOINT0_SIZE,             // bMaxPacketSize0
  LSB(VENDOR_ID), MSB(VENDOR_ID),     // idVendor
  LSB(PRODUCT_ID), MSB(PRODUCT_ID),   // idProduct
  0x00, 0x01,             // bcdDevice
  1,                  // iManufacturer
  2,                  // iProduct
  0,                  // iSerialNumber
  1                   // bNumConfigurations
};

// Keyboard Protocol 1, HID 1.11 spec, Appendix B, page 59-60
static uint8_t const PROGMEM keyboard_hid_report_desc[] = {
  0x05, 0x01,          // Usage Page (Generic Desktop),
  0x09, 0x06,          // Usage (Keyboard),
  0xA1, 0x01,          // Collection (Application),
  0x75, 0x01,          //   Report Size (1),
  0x95, 0x08,          //   Report Count (8),
  0x05, 0x07,          //   Usage Page (Key Codes),
  0x19, 0xE0,          //   Usage Minimum (224),
  0x29, 0xE7,          //   Usage Maximum (231),
  0x15, 0x00,          //   Logical Minimum (0),
  0x25, 0x01,          //   Logical Maximum (1),
  0x81, 0x02,          //   Input (Data, Variable, Absolute), ;Modifier byte
  0x95, 0x01,          //   Report Count (1),
  0x75, 0x08,          //   Report Size (8),
  0x81, 0x03,          //   Input (Constant),                 ;Reserved byte
  0x95, 0x05,          //   Report Count (5),
  0x75, 0x01,          //   Report Size (1),
  0x05, 0x08,          //   Usage Page (LEDs),
  0x19, 0x01,          //   Usage Minimum (1),
  0x29, 0x05,          //   Usage Maximum (5),
  0x91, 0x02,          //   Output (Data, Variable, Absolute), ;LED report
  0x95, 0x01,          //   Report Count (1),
  0x75, 0x03,          //   Report Size (3),
  0x91, 0x03,          //   Output (Constant),                 ;LED report padding
  0x95, 0x06,          //   Report Count (6),
  0x75, 0x08,          //   Report Size (8),
  0x15, 0x00,          //   Logical Minimum (0),
  0x25, 0x68,          //   Logical Maximum(104),
  0x05, 0x07,          //   Usage Page (Key Codes),
  0x19, 0x00,          //   Usage Minimum (0),
  0x29, 0x68,          //   Usage Maximum (104),
  0x81, 0x00,          //   Input (Data, Array),
  0xc0                 // End Collection
};

#define CONFIG1_DESC_SIZE        (9+9+9+7)
#define KEYBOARD_HID_DESC_OFFSET (9+9)
static uint8_t const PROGMEM config1_descriptor[CONFIG1_DESC_SIZE] = {
  // configuration descriptor, USB spec 9.6.3, page 264-266, Table 9-10
  9,                  // bLength;
  2,                  // bDescriptorType;
  LSB(CONFIG1_DESC_SIZE),         // wTotalLength
  MSB(CONFIG1_DESC_SIZE),
  1,                  // bNumInterfaces
  1,                  // bConfigurationValue
  0,                  // iConfiguration
  0xC0,                   // bmAttributes
  50,                 // bMaxPower
  // interface descriptor, USB spec 9.6.5, page 267-269, Table 9-12
  9,                  // bLength
  4,                  // bDescriptorType
  KEYBOARD_INTERFACE,         // bInterfaceNumber
  0,                  // bAlternateSetting
  1,                  // bNumEndpoints
  0x03,                   // bInterfaceClass (0x03 = HID)
  0x01,                   // bInterfaceSubClass (0x01 = Boot)
  0x01,                   // bInterfaceProtocol (0x01 = Keyboard)
  0,                  // iInterface
  // HID interface descriptor, HID 1.11 spec, section 6.2.1
  9,                  // bLength
  0x21,                   // bDescriptorType
  0x11, 0x01,             // bcdHID
  0,                  // bCountryCode
  1,                  // bNumDescriptors
  0x22,                   // bDescriptorType
  sizeof(keyboard_hid_report_desc),   // wDescriptorLength
  0,
  // endpoint descriptor, USB spec 9.6.6, page 269-271, Table 9-13
  7,                  // bLength
  5,                  // bDescriptorType
  KEYBOARD_ENDPOINT | 0x80,       // bEndpointAddress
  0x03,                   // bmAttributes (0x03=intr)
  KEYBOARD_SIZE, 0,           // wMaxPacketSize
  1                   // bInterval
};

// If you're desperate for a little extra code memory, these strings
// can be completely removed if iManufacturer, iProduct, iSerialNumber
// in the device desciptor are changed to zeros.
struct usb_string_descriptor_struct {
  uint8_t bLength;
  uint8_t bDescriptorType;
  int16_t wString[];
};
static struct usb_string_descriptor_struct const PROGMEM string0 = {
  4,
  3,
  {0x0409}
};
static struct usb_string_descriptor_struct const PROGMEM string1 = {
  sizeof(STR_MANUFACTURER),
  3,
  STR_MANUFACTURER
};
static struct usb_string_descriptor_struct const PROGMEM string2 = {
  sizeof(STR_PRODUCT),
  3,
  STR_PRODUCT
};

// This table defines which descriptor data is sent for each specific
// request from the host (in wValue and wIndex).
static struct descriptor_list_struct {
  uint16_t    wValue;
  uint16_t    wIndex;
  const uint8_t   *addr;
  uint8_t     length;
} const PROGMEM descriptor_list[] = {
  {0x0100, 0x0000, device_descriptor, sizeof(device_descriptor)},
  {0x0200, 0x0000, config1_descriptor, sizeof(config1_descriptor)},
  {0x2200, KEYBOARD_INTERFACE, keyboard_hid_report_desc, sizeof(keyboard_hid_report_desc)},
  {0x2100, KEYBOARD_INTERFACE, config1_descriptor+KEYBOARD_HID_DESC_OFFSET, 9},
  {0x0300, 0x0000, (const uint8_t *)&string0, 4},
  {0x0301, 0x0409, (const uint8_t *)&string1, sizeof(STR_MANUFACTURER)},
  {0x0302, 0x0409, (const uint8_t *)&string2, sizeof(STR_PRODUCT)}
};
#define NUM_DESC_LIST (sizeof(descriptor_list)/sizeof(struct descriptor_list_struct))


/**************************************************************************
 *
 *  Variables - these are the only non-stack RAM usage
 *
 **************************************************************************/

// zero when we are not configured, non-zero when enumerated
static volatile uint8_t usb_configuration=0;

// which modifier keys are currently pressed
// 1=left ctrl,    2=left shift,   4=left alt,    8=left gui
// 16=right ctrl, 32=right shift, 64=right alt, 128=right gui
uint8_t keyboard_modifier_keys=0;

// which keys are currently pressed, up to 6 keys may be down at once
uint8_t keyboard_keys[6]={0,0,0,0,0,0};

// protocol setting from the host.  We use exactly the same report
// either way, so this variable only stores the setting since we
// are required to be able to report which setting is in use.
static uint8_t keyboard_protocol=1;

// the idle configuration, how often we send the report to the
// host (ms * 4) even when it hasn't changed
static uint8_t keyboard_idle_config=125;

// count until idle timeout
static uint8_t keyboard_idle_count=0;

// 1=num lock, 2=caps lock, 4=scroll lock, 8=compose, 16=kana
volatile uint8_t keyboard_leds=0;


/**************************************************************************
 *
 *  Public Functions - these are the API intended for the user
 *
 **************************************************************************/


// initialize USB
void usb_init(void)
{
  HW_CONFIG();
  USB_FREEZE();   // enable USB
  PLL_CONFIG();               // config PLL
  while (!(PLLCSR & (1<<PLOCK))) ;    // wait for PLL lock
  USB_CONFIG();               // start USB clock
  UDCON = 0;              // enable attach resistor
  usb_configuration = 0;
  UDIEN = (1<<EORSTE)|(1<<SOFE);
  sei();
}

// return 0 if the USB is not configured, or the configuration
// number selected by the HOST
uint8_t usb_configured(void)
{
  return usb_configuration;
}


// perform a single keystroke
int8_t usb_keyboard_press(uint8_t key, uint8_t modifier)
{
  int8_t r;

  keyboard_modifier_keys = modifier;
  keyboard_keys[0] = key;
  r = usb_keyboard_send();
  if (r) return r;
  keyboard_modifier_keys = 0;
  keyboard_keys[0] = 0;
  return usb_keyboard_send();
}

// send the contents of keyboard_keys and keyboard_modifier_keys
int8_t usb_keyboard_send(void)
{
  uint8_t i, intr_state, timeout;

  if (!usb_configuration) return -1;
  intr_state = SREG;
  cli();
  UENUM = KEYBOARD_ENDPOINT;
  timeout = UDFNUML + 50;
  while (1) {
    // are we ready to transmit?
    if (UEINTX & (1<<RWAL)) break;
    SREG = intr_state;
    // has the USB gone offline?
    if (!usb_configuration) return -1;
    // have we waited too long?
    if (UDFNUML == timeout) return -1;
    // get ready to try checking again
    intr_state = SREG;
    cli();
    UENUM = KEYBOARD_ENDPOINT;
  }
  UEDATX = keyboard_modifier_keys;
  UEDATX = 0;
  for (i=0; i<6; i++) {
    UEDATX = keyboard_keys[i];
  }
  UEINTX = 0x3A;
  keyboard_idle_count = 0;
  SREG = intr_state;
  return 0;
}

// my own wrapper, mangled to work with the PoC microsheme FFI
int16_t usb_send(int modifiers,
                 int key0, int key1, int key2,
                 int key3, int key4, int key5) {
  keyboard_modifier_keys = (uint8_t) modifiers;
  keyboard_keys[0] = (uint8_t)key0;
  keyboard_keys[1] = (uint8_t)key1;
  keyboard_keys[2] = (uint8_t)key2;
  keyboard_keys[3] = (uint8_t)key3;
  keyboard_keys[4] = (uint8_t)key4;
  keyboard_keys[5] = (uint8_t)key5;
  return usb_keyboard_send();
}

/**************************************************************************
 *
 *  Private Functions - not intended for general user consumption....
 *
 **************************************************************************/



// USB Device Interrupt - handle all device-level events
// the transmit buffer flushing is triggered by the start of frame
//
ISR(USB_GEN_vect)
{
  uint8_t intbits, t, i;
  static uint8_t div4=0;

  intbits = UDINT;
  UDINT = 0;
  if (intbits & (1<<EORSTI)) {
    UENUM = 0;
    UECONX = 1;
    UECFG0X = EP_TYPE_CONTROL;
    UECFG1X = EP_SIZE(ENDPOINT0_SIZE) | EP_SINGLE_BUFFER;
    UEIENX = (1<<RXSTPE);
    usb_configuration = 0;
  }
  if ((intbits & (1<<SOFI)) && usb_configuration) {
    if (keyboard_idle_config && (++div4 & 3) == 0) {
      UENUM = KEYBOARD_ENDPOINT;
      if (UEINTX & (1<<RWAL)) {
        keyboard_idle_count++;
        if (keyboard_idle_count == keyboard_idle_config) {
          keyboard_idle_count = 0;
          UEDATX = keyboard_modifier_keys;
          UEDATX = 0;
          for (i=0; i<6; i++) {
            UEDATX = keyboard_keys[i];
          }
          UEINTX = 0x3A;
        }
      }
    }
  }
}



// Misc functions to wait for ready and send/receive packets
static inline void usb_wait_in_ready(void)
{
  while (!(UEINTX & (1<<TXINI))) ;
}
static inline void usb_send_in(void)
{
  UEINTX = ~(1<<TXINI);
}
static inline void usb_wait_receive_out(void)
{
  while (!(UEINTX & (1<<RXOUTI))) ;
}
static inline void usb_ack_out(void)
{
  UEINTX = ~(1<<RXOUTI);
}



// USB Endpoint Interrupt - endpoint 0 is handled here.  The
// other endpoints are manipulated by the user-callable
// functions, and the start-of-frame interrupt.
//
ISR(USB_COM_vect)
{
  uint8_t intbits;
  const uint8_t *list;
  const uint8_t *cfg;
  uint8_t i, n, len, en;
  uint8_t bmRequestType;
  uint8_t bRequest;
  uint16_t wValue;
  uint16_t wIndex;
  uint16_t wLength;
  uint16_t desc_val;
  const uint8_t *desc_addr;
  uint8_t desc_length;

  UENUM = 0;
  intbits = UEINTX;
  if (intbits & (1<<RXSTPI)) {
    bmRequestType = UEDATX;
    bRequest = UEDATX;
    wValue = UEDATX;
    wValue |= (UEDATX << 8);
    wIndex = UEDATX;
    wIndex |= (UEDATX << 8);
    wLength = UEDATX;
    wLength |= (UEDATX << 8);
    UEINTX = ~((1<<RXSTPI) | (1<<RXOUTI) | (1<<TXINI));
    if (bRequest == GET_DESCRIPTOR) {
      list = (const uint8_t *)descriptor_list;
      for (i=0; ; i++) {
        if (i >= NUM_DESC_LIST) {
          UECONX = (1<<STALLRQ)|(1<<EPEN);  //stall
          return;
        }
        desc_val = pgm_read_word(list);
        if (desc_val != wValue) {
          list += sizeof(struct descriptor_list_struct);
          continue;
        }
        list += 2;
        desc_val = pgm_read_word(list);
        if (desc_val != wIndex) {
          list += sizeof(struct descriptor_list_struct)-2;
          continue;
        }
        list += 2;
        desc_addr = (const uint8_t *)pgm_read_word(list);
        list += 2;
        desc_length = pgm_read_byte(list);
        break;
      }
      len = (wLength < 256) ? wLength : 255;
      if (len > desc_length) len = desc_length;
      do {
        // wait for host ready for IN packet
        do {
          i = UEINTX;
        } while (!(i & ((1<<TXINI)|(1<<RXOUTI))));
        if (i & (1<<RXOUTI)) return;    // abort
        // send IN packet
        n = len < ENDPOINT0_SIZE ? len : ENDPOINT0_SIZE;
        for (i = n; i; i--) {
          UEDATX = pgm_read_byte(desc_addr++);
        }
        len -= n;
        usb_send_in();
      } while (len || n == ENDPOINT0_SIZE);
      return;
    }
    if (bRequest == SET_ADDRESS) {
      usb_send_in();
      usb_wait_in_ready();
      UDADDR = wValue | (1<<ADDEN);
      return;
    }
    if (bRequest == SET_CONFIGURATION && bmRequestType == 0) {
      usb_configuration = wValue;
      usb_send_in();
      cfg = endpoint_config_table;
      for (i=1; i<5; i++) {
        UENUM = i;
        en = pgm_read_byte(cfg++);
        UECONX = en;
        if (en) {
          UECFG0X = pgm_read_byte(cfg++);
          UECFG1X = pgm_read_byte(cfg++);
        }
      }
      UERST = 0x1E;
      UERST = 0;
      return;
    }
    if (bRequest == GET_CONFIGURATION && bmRequestType == 0x80) {
      usb_wait_in_ready();
      UEDATX = usb_configuration;
      usb_send_in();
      return;
    }

    if (bRequest == GET_STATUS) {
      usb_wait_in_ready();
      i = 0;
#ifdef SUPPORT_ENDPOINT_HALT
      if (bmRequestType == 0x82) {
        UENUM = wIndex;
        if (UECONX & (1<<STALLRQ)) i = 1;
        UENUM = 0;
      }
#endif
      UEDATX = i;
      UEDATX = 0;
      usb_send_in();
      return;
    }
#ifdef SUPPORT_ENDPOINT_HALT
    if ((bRequest == CLEAR_FEATURE || bRequest == SET_FEATURE)
        && bmRequestType == 0x02 && wValue == 0) {
      i = wIndex & 0x7F;
      if (i >= 1 && i <= MAX_ENDPOINT) {
        usb_send_in();
        UENUM = i;
        if (bRequest == SET_FEATURE) {
          UECONX = (1<<STALLRQ)|(1<<EPEN);
        } else {
          UECONX = (1<<STALLRQC)|(1<<RSTDT)|(1<<EPEN);
          UERST = (1 << i);
          UERST = 0;
        }
        return;
      }
    }
#endif
    if (wIndex == KEYBOARD_INTERFACE) {
      if (bmRequestType == 0xA1) {
        if (bRequest == HID_GET_REPORT) {
          usb_wait_in_ready();
          UEDATX = keyboard_modifier_keys;
          UEDATX = 0;
          for (i=0; i<6; i++) {
            UEDATX = keyboard_keys[i];
          }
          usb_send_in();
          return;
        }
        if (bRequest == HID_GET_IDLE) {
          usb_wait_in_ready();
          UEDATX = keyboard_idle_config;
          usb_send_in();
          return;
        }
        if (bRequest == HID_GET_PROTOCOL) {
          usb_wait_in_ready();
          UEDATX = keyboard_protocol;
          usb_send_in();
          return;
        }
      }
      if (bmRequestType == 0x21) {
        if (bRequest == HID_SET_REPORT) {
          usb_wait_receive_out();
          keyboard_leds = UEDATX;
          usb_ack_out();
          usb_send_in();
          return;
        }
        if (bRequest == HID_SET_IDLE) {
          keyboard_idle_config = (wValue >> 8);
          keyboard_idle_count = 0;
          usb_send_in();
          return;
        }
        if (bRequest == HID_SET_PROTOCOL) {
          keyboard_protocol = wValue;
          usb_send_in();
          return;
        }
      }
    }
  }
  UECONX = (1<<STALLRQ) | (1<<EPEN);  // stall
}

void reset(void) {
  UDCON = 1; USBCON = (1<<FRZCLK); UCSR1B = 0;
  _delay_ms(5);
  EIMSK = 0; PCICR = 0; SPCR = 0; ACSR = 0; EECR = 0; ADCSRA = 0;
  TIMSK0 = 0; TIMSK1 = 0; TIMSK3 = 0; TIMSK4 = 0; UCSR1B = 0; TWCR = 0;
  DDRB = 0; DDRC = 0; DDRD = 0; DDRE = 0; DDRF = 0; TWCR = 0;
  PORTB = 0; PORTC = 0; PORTD = 0; PORTE = 0; PORTF = 0;
  *(uint16_t *)0x0800 = 0x7777;
  wdt_enable(WDTO_120MS);
  asm volatile("jmp 0x7E00");
};