root / demos / hunter_prey / lib / src / libwireless / xbee.c @ 1828
History | View | Annotate | Download (21.7 KB)
1 | 1828 | emullini | /**
|
---|---|---|---|
2 | * Copyright (c) 2007 Colony Project
|
||
3 | *
|
||
4 | * Permission is hereby granted, free of charge, to any person
|
||
5 | * obtaining a copy of this software and associated documentation
|
||
6 | * files (the "Software"), to deal in the Software without
|
||
7 | * restriction, including without limitation the rights to use,
|
||
8 | * copy, modify, merge, publish, distribute, sublicense, and/or sell
|
||
9 | * copies of the Software, and to permit persons to whom the
|
||
10 | * Software is furnished to do so, subject to the following
|
||
11 | * conditions:
|
||
12 | *
|
||
13 | * The above copyright notice and this permission notice shall be
|
||
14 | * included in all copies or substantial portions of the Software.
|
||
15 | *
|
||
16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
||
17 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
|
||
18 | * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
||
19 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
|
||
20 | * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
||
21 | * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
|
||
22 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
|
||
23 | * OTHER DEALINGS IN THE SOFTWARE.
|
||
24 | **/
|
||
25 | |||
26 | /**
|
||
27 | * @file xbee.c
|
||
28 | * @brief XBee Interface
|
||
29 | *
|
||
30 | * Implementation of low level communication with the XBee in API mode.
|
||
31 | *
|
||
32 | * @author Brian Coltin, Colony Project, CMU Robotics Club
|
||
33 | **/
|
||
34 | |||
35 | #include "xbee.h" |
||
36 | #include "wl_defs.h" |
||
37 | |||
38 | #ifndef ROBOT
|
||
39 | |||
40 | #include <fcntl.h> |
||
41 | #include <unistd.h> |
||
42 | #include <pthread.h> |
||
43 | #include <errno.h> |
||
44 | #include <termios.h> |
||
45 | #include <stdio.h> |
||
46 | #include <stdlib.h> |
||
47 | |||
48 | #else
|
||
49 | |||
50 | #include <serial.h> |
||
51 | #include <avr/interrupt.h> |
||
52 | #include <util/delay.h> |
||
53 | |||
54 | #endif
|
||
55 | |||
56 | #include <string.h> |
||
57 | |||
58 | #define XBEE_FRAME_START 0x7E |
||
59 | #define XBEE_GET_PACKET_TIMEOUT 1000 |
||
60 | |||
61 | /*Frame Types*/
|
||
62 | #define XBEE_FRAME_STATUS 0x8A |
||
63 | #define XBEE_FRAME_AT_COMMAND 0x08 |
||
64 | #define XBEE_FRAME_AT_COMMAND_RESPONSE 0x88 |
||
65 | #define XBEE_FRAME_TX_REQUEST_64 0x00 |
||
66 | #define XBEE_FRAME_TX_REQUEST_16 0x01 |
||
67 | #define XBEE_FRAME_TX_STATUS XBEE_TX_STATUS
|
||
68 | #define XBEE_FRAME_RX_64 0x80 |
||
69 | #define XBEE_FRAME_RX_16 XBEE_RX
|
||
70 | |||
71 | /*Internal Function Prototypes*/
|
||
72 | |||
73 | /*I/O Functions*/
|
||
74 | static int xbee_send(char* buf, int size); |
||
75 | static int xbee_send_string(char* c); |
||
76 | |||
77 | #ifndef ROBOT
|
||
78 | static int xbee_read(char* buf, int size); |
||
79 | #endif
|
||
80 | |||
81 | /*Command Mode Functions
|
||
82 | * Called during initialization.
|
||
83 | */
|
||
84 | static int xbee_enter_command_mode(void); |
||
85 | static int xbee_exit_command_mode(void); |
||
86 | static int xbee_enter_api_mode(void); |
||
87 | static int xbee_exit_api_mode(void); |
||
88 | static int xbee_wait_for_string(char* s, int len); |
||
89 | static int xbee_wait_for_ok(void); |
||
90 | |||
91 | /*API Mode Functions*/
|
||
92 | |||
93 | static int xbee_handle_packet(char* packet, int len); |
||
94 | static void xbee_handle_at_command_response(char* command, char result, char* extra, int extraLen); |
||
95 | static void xbee_handle_status(char status); |
||
96 | static int xbee_verify_checksum(char* packet, int len); |
||
97 | static char xbee_compute_checksum(char* packet, int len); |
||
98 | static int xbee_send_frame(char* buf, int len); |
||
99 | static int xbee_send_read_at_command(char* command); |
||
100 | static int xbee_send_modify_at_command(char* command, char* value); |
||
101 | |||
102 | /*Global Variables*/
|
||
103 | |||
104 | #ifndef ROBOT
|
||
105 | static char* xbee_com_port = XBEE_PORT_DEFAULT; |
||
106 | static int xbee_stream; |
||
107 | static pthread_t* xbee_listen_thread;
|
||
108 | #endif
|
||
109 | |||
110 | // TODO: is this a good size?
|
||
111 | #define XBEE_BUFFER_SIZE 128 |
||
112 | #define PACKET_BUFFER_SIZE 108 |
||
113 | // a buffer for data received from the XBee
|
||
114 | char arrival_buf[XBEE_BUFFER_SIZE];
|
||
115 | // location of last unread byte in buffer
|
||
116 | volatile int buffer_last = 0; |
||
117 | // first unread byte in buffer
|
||
118 | volatile int buffer_first = 0; |
||
119 | |||
120 | |||
121 | //used to store packets as they are read
|
||
122 | static char xbee_buf[PACKET_BUFFER_SIZE]; |
||
123 | static int currentBufPos = 0; |
||
124 | |||
125 | //XBee status
|
||
126 | static unsigned int xbee_panID = XBEE_PAN_DEFAULT; |
||
127 | static unsigned int xbee_pending_panID = XBEE_PAN_DEFAULT; |
||
128 | static int xbee_channel = XBEE_CHANNEL_DEFAULT; |
||
129 | static int xbee_pending_channel = XBEE_CHANNEL_DEFAULT; |
||
130 | static volatile unsigned int xbee_address = 0; |
||
131 | |||
132 | /*Function Implementations*/
|
||
133 | |||
134 | #ifdef ROBOT
|
||
135 | |||
136 | /**
|
||
137 | * Interrupt for the robot. Adds bytes received from the xbee
|
||
138 | * to the buffer.
|
||
139 | **/
|
||
140 | #ifndef FIREFLY
|
||
141 | ISR(USART1_RX_vect) |
||
142 | { |
||
143 | char c = UDR1;
|
||
144 | arrival_buf[buffer_last] = c; |
||
145 | int t = buffer_last + 1; |
||
146 | if (t == XBEE_BUFFER_SIZE)
|
||
147 | t = 0;
|
||
148 | if (t == buffer_first)
|
||
149 | { |
||
150 | WL_DEBUG_PRINT("\nOut of space in buffer.\n");
|
||
151 | } |
||
152 | buffer_last = t; |
||
153 | } |
||
154 | #else
|
||
155 | SIGNAL(SIG_USART0_RECV) |
||
156 | { |
||
157 | char c = UDR0;
|
||
158 | arrival_buf[buffer_last] = c; |
||
159 | int t = buffer_last + 1; |
||
160 | if (t == XBEE_BUFFER_SIZE)
|
||
161 | t = 0;
|
||
162 | if (t == buffer_first)
|
||
163 | { |
||
164 | WL_DEBUG_PRINT("Out of space in buffer.\n");
|
||
165 | } |
||
166 | buffer_last = t; |
||
167 | } |
||
168 | #endif
|
||
169 | |||
170 | #else
|
||
171 | |||
172 | // Computer code
|
||
173 | |||
174 | /**
|
||
175 | * Thread that listens to the xbee.
|
||
176 | **/
|
||
177 | static void* listen_to_xbee(void* x) |
||
178 | { |
||
179 | char c;
|
||
180 | while (1) |
||
181 | { |
||
182 | if (xbee_read(&c, 1) != 0) { |
||
183 | WL_DEBUG_PRINT("xbee_read failed.\n");
|
||
184 | return NULL; |
||
185 | } |
||
186 | |||
187 | arrival_buf[buffer_last] = c; |
||
188 | int t = buffer_last + 1; |
||
189 | if (t == XBEE_BUFFER_SIZE)
|
||
190 | t = 0;
|
||
191 | if (t == buffer_first)
|
||
192 | { |
||
193 | WL_DEBUG_PRINT("Out of space in buffer.\n");
|
||
194 | } |
||
195 | buffer_last = t; |
||
196 | |||
197 | usleep(1000);
|
||
198 | } |
||
199 | |||
200 | return NULL; |
||
201 | } |
||
202 | |||
203 | #endif
|
||
204 | |||
205 | /**
|
||
206 | * Initializes the XBee library so that other functions may be used.
|
||
207 | **/
|
||
208 | int xbee_lib_init()
|
||
209 | { |
||
210 | WL_DEBUG_PRINT("in xbee_init\n");
|
||
211 | #ifdef ROBOT
|
||
212 | |||
213 | //enable the receiving interrupt
|
||
214 | #ifdef FIREFLY
|
||
215 | UCSR0B |= _BV(RXCIE) | _BV(RXEN); |
||
216 | #else
|
||
217 | #ifdef BAYBOARD
|
||
218 | UCSR1B |= _BV(RXCIE1); |
||
219 | #else
|
||
220 | UCSR1B |= _BV(RXCIE); |
||
221 | #endif
|
||
222 | #endif
|
||
223 | sei(); |
||
224 | #else
|
||
225 | xbee_stream = open(xbee_com_port, O_RDWR); |
||
226 | if (xbee_stream == -1/* || lockf(xbee_stream, F_TEST, 0) != 0*/) |
||
227 | { |
||
228 | WL_DEBUG_PRINT("Failed to open connection to XBee on port ");
|
||
229 | WL_DEBUG_PRINT_INT(xbee_com_port); |
||
230 | WL_DEBUG_PRINT(".\n");
|
||
231 | return -1; |
||
232 | } else {
|
||
233 | WL_DEBUG_PRINT("Successfully opened connection to XBee on port ");
|
||
234 | WL_DEBUG_PRINT_INT(xbee_com_port); |
||
235 | WL_DEBUG_PRINT(".\n");
|
||
236 | } |
||
237 | |||
238 | // set baud rate, etc. correctly
|
||
239 | struct termios options;
|
||
240 | |||
241 | tcgetattr(xbee_stream, &options); |
||
242 | cfsetispeed(&options, B9600); |
||
243 | cfsetospeed(&options, B9600); |
||
244 | options.c_iflag &= ~ICRNL; |
||
245 | options.c_oflag &= ~OCRNL; |
||
246 | options.c_cflag |= (CLOCAL | CREAD); |
||
247 | options.c_cflag &= ~PARENB; |
||
248 | options.c_cflag &= ~CSTOPB; |
||
249 | options.c_cflag &= ~CSIZE; |
||
250 | options.c_cflag |= CS8; |
||
251 | options.c_lflag &= ~ICANON; |
||
252 | options.c_cc[VMIN] = 1;
|
||
253 | options.c_cc[VTIME] = 50;
|
||
254 | |||
255 | if (tcsetattr(xbee_stream, TCSANOW, &options))
|
||
256 | { |
||
257 | WL_DEBUG_PRINT("Error setting attributes.\n");
|
||
258 | return -1; |
||
259 | } |
||
260 | |||
261 | xbee_listen_thread = (pthread_t*)malloc(sizeof(pthread_t));
|
||
262 | if (xbee_listen_thread == NULL) |
||
263 | { |
||
264 | WL_DEBUG_PRINT("Malloc failed.\n");
|
||
265 | return -1; |
||
266 | } |
||
267 | |||
268 | int ret = pthread_create(xbee_listen_thread, NULL, listen_to_xbee, NULL); |
||
269 | if (ret)
|
||
270 | { |
||
271 | WL_DEBUG_PRINT("Failed to create listener thread.\n");
|
||
272 | return -1; |
||
273 | } |
||
274 | #endif
|
||
275 | |||
276 | WL_DEBUG_PRINT("Entering command mode.\n");
|
||
277 | |||
278 | if (xbee_enter_command_mode() != 0) { |
||
279 | return -1; |
||
280 | } |
||
281 | |||
282 | WL_DEBUG_PRINT("Entered command mode.\n");
|
||
283 | |||
284 | if (xbee_enter_api_mode() != 0) { |
||
285 | return -1; |
||
286 | } |
||
287 | |||
288 | WL_DEBUG_PRINT("Entered api mode.\n");
|
||
289 | |||
290 | if (xbee_exit_command_mode() != 0) { |
||
291 | return -1; |
||
292 | } |
||
293 | |||
294 | WL_DEBUG_PRINT("Left command mode.\n");
|
||
295 | |||
296 | if (xbee_send_read_at_command("MY")) { |
||
297 | return -1; |
||
298 | } |
||
299 | WL_DEBUG_PRINT("Getting ATMY address.\n");
|
||
300 | |||
301 | #ifndef ROBOT
|
||
302 | int i;
|
||
303 | for (i = 0; xbee_address == 0 && i < XBEE_GET_PACKET_TIMEOUT; i++) { |
||
304 | ret = xbee_get_packet(NULL);
|
||
305 | |||
306 | usleep(1000);
|
||
307 | |||
308 | /* if (ret == -1) { */
|
||
309 | /* WL_DEBUG_PRINT("xbee_get_packet(NULL) failed.\n"); */
|
||
310 | /* return -1; */
|
||
311 | /* } */
|
||
312 | } |
||
313 | #else
|
||
314 | //wait to return until the address is set
|
||
315 | //TODO: this shouldn't wait indefinitely. There should be some sort of reasonable timeout
|
||
316 | // so if the address is never set right, an error can be returned instead of having the
|
||
317 | // robot hang forever
|
||
318 | while (xbee_address == 0) { |
||
319 | xbee_get_packet(NULL);
|
||
320 | } |
||
321 | #endif
|
||
322 | WL_DEBUG_PRINT("Got ATMY address.\n");
|
||
323 | |||
324 | #ifndef ROBOT
|
||
325 | if (i == XBEE_GET_PACKET_TIMEOUT) { // We timed-out. |
||
326 | |||
327 | WL_DEBUG_PRINT("xbee_get_packet timed out.\n");
|
||
328 | return -1; |
||
329 | } else {
|
||
330 | return 0; |
||
331 | } |
||
332 | #else
|
||
333 | return 0; |
||
334 | #endif
|
||
335 | } |
||
336 | |||
337 | /**
|
||
338 | * Call when finished using the XBee library. This releases
|
||
339 | * all sued resources.
|
||
340 | **/
|
||
341 | void xbee_terminate()
|
||
342 | { |
||
343 | #ifndef ROBOT
|
||
344 | pthread_cancel(*xbee_listen_thread); |
||
345 | pthread_join(*xbee_listen_thread, NULL);
|
||
346 | free(xbee_listen_thread); |
||
347 | lockf(xbee_stream, F_ULOCK, 0);
|
||
348 | close(xbee_stream); |
||
349 | #else
|
||
350 | xbee_exit_api_mode(); |
||
351 | #endif
|
||
352 | } |
||
353 | |||
354 | /**
|
||
355 | * Send a buffer buf of size bytes to the XBee.
|
||
356 | *
|
||
357 | * @param buf the buffer of data to send
|
||
358 | * @param size the number of bytes to send
|
||
359 | **/
|
||
360 | static int xbee_send(char* buf, int size) |
||
361 | { |
||
362 | #ifdef ROBOT
|
||
363 | int i;
|
||
364 | for (i = 0; i < size; i++) { |
||
365 | xbee_putc(buf[i]); |
||
366 | } |
||
367 | |||
368 | return 0; |
||
369 | |||
370 | #else
|
||
371 | |||
372 | int ret = write(xbee_stream, buf, size);
|
||
373 | //success
|
||
374 | if (ret == size)
|
||
375 | return 0; |
||
376 | if (ret == -1) |
||
377 | { |
||
378 | //interrupted by system signal, probably timer interrupt.
|
||
379 | //just try again
|
||
380 | if (errno == 4) |
||
381 | { |
||
382 | return xbee_send(buf, size);
|
||
383 | } |
||
384 | WL_DEBUG_PRINT("Failed to write to xbee\r\n");
|
||
385 | return -1; |
||
386 | } |
||
387 | |||
388 | //write was interrupted after writing ret bytes
|
||
389 | return xbee_send(buf + ret, size - ret);
|
||
390 | #endif
|
||
391 | } |
||
392 | |||
393 | /**
|
||
394 | * Sends a string to the XBee.
|
||
395 | *
|
||
396 | * @param c the string to send to the XBEE
|
||
397 | **/
|
||
398 | static int xbee_send_string(char* c) |
||
399 | { |
||
400 | return xbee_send(c, strlen(c));
|
||
401 | } |
||
402 | |||
403 | #ifndef ROBOT
|
||
404 | static int xbee_read(char* buf, int size) |
||
405 | { |
||
406 | if (read(xbee_stream, buf, size) == -1) { |
||
407 | WL_DEBUG_PRINT("Failed to read from xbee.\r\n");
|
||
408 | return -1; |
||
409 | } |
||
410 | |||
411 | return 0; |
||
412 | } |
||
413 | #endif
|
||
414 | |||
415 | /**
|
||
416 | * Enter into command mode.
|
||
417 | **/
|
||
418 | static int xbee_enter_command_mode() |
||
419 | { |
||
420 | if (xbee_send_string("+++") != 0) { |
||
421 | return -1; |
||
422 | } |
||
423 | |||
424 | if (xbee_wait_for_ok() != 0) { |
||
425 | return -1; |
||
426 | } |
||
427 | return 0; |
||
428 | } |
||
429 | |||
430 | /**
|
||
431 | * Exit from command mode.
|
||
432 | **/
|
||
433 | static int xbee_exit_command_mode() |
||
434 | { |
||
435 | if (xbee_send_string("ATCN\r") != 0) { |
||
436 | return -1; |
||
437 | } |
||
438 | |||
439 | xbee_wait_for_ok(); |
||
440 | |||
441 | return 0; |
||
442 | } |
||
443 | |||
444 | /**
|
||
445 | * Enter API mode.
|
||
446 | **/
|
||
447 | static int xbee_enter_api_mode() |
||
448 | { |
||
449 | if (xbee_send_string("ATAP 1\r") != 0) { |
||
450 | return -1; |
||
451 | } |
||
452 | xbee_wait_for_ok(); |
||
453 | |||
454 | return 0; |
||
455 | } |
||
456 | |||
457 | /**
|
||
458 | * Exit API mode.
|
||
459 | **/
|
||
460 | static int xbee_exit_api_mode() |
||
461 | { |
||
462 | if (xbee_send_modify_at_command("AP","0") != 0) { |
||
463 | return -1; |
||
464 | } |
||
465 | |||
466 | return 0; |
||
467 | } |
||
468 | |||
469 | /**
|
||
470 | * Wait until the string "OK\r" is received from the XBee.
|
||
471 | **/
|
||
472 | static int xbee_wait_for_ok() |
||
473 | { |
||
474 | return xbee_wait_for_string("OK\r", 3); |
||
475 | } |
||
476 | |||
477 | /**
|
||
478 | * Delay until the specified string is received from
|
||
479 | * the XBee. Discards all other XBee data.
|
||
480 | *
|
||
481 | * @param s the string to receive
|
||
482 | * @param len the length of the string
|
||
483 | **/
|
||
484 | static int xbee_wait_for_string(char* s, int len) |
||
485 | { |
||
486 | char* curr = s;
|
||
487 | while (curr - s < len) {
|
||
488 | // check if buffer is empty
|
||
489 | if (buffer_last != buffer_first) {
|
||
490 | char c = arrival_buf[buffer_first++];
|
||
491 | if (buffer_first == XBEE_BUFFER_SIZE) {
|
||
492 | buffer_first = 0;
|
||
493 | } |
||
494 | |||
495 | if (c == *curr) {
|
||
496 | curr++; |
||
497 | } else {
|
||
498 | #ifndef ROBOT
|
||
499 | //return -1; // Computer is less forgiving.
|
||
500 | curr = s; |
||
501 | #else
|
||
502 | curr = s; |
||
503 | #endif
|
||
504 | } |
||
505 | } // else buffer is empty.
|
||
506 | |||
507 | #ifndef ROBOT
|
||
508 | usleep(100);
|
||
509 | #endif
|
||
510 | } |
||
511 | |||
512 | return 0; |
||
513 | } |
||
514 | |||
515 | /**
|
||
516 | * Verifies that the packets checksum is correct.
|
||
517 | * (If the checksum is correct, the sum of the bytes
|
||
518 | * is 0xFF.)
|
||
519 | *
|
||
520 | * @param packet the packet received. This includes the first
|
||
521 | * three bytes, which are header information from the XBee.
|
||
522 | *
|
||
523 | * @param len The length of the packet received from the XBee
|
||
524 | *
|
||
525 | * @return 0 if the checksum is incorrect, nonzero
|
||
526 | * otherwise
|
||
527 | **/
|
||
528 | int xbee_verify_checksum(char* packet, int len) |
||
529 | { |
||
530 | unsigned char sum = 0; |
||
531 | int i;
|
||
532 | for (i = 3; i < len; i++) |
||
533 | sum += (unsigned char)packet[i]; |
||
534 | return sum == 0xFF; |
||
535 | } |
||
536 | |||
537 | /**
|
||
538 | * Returns the checksum of the given packet.
|
||
539 | *
|
||
540 | * @param buf the data for the packet to send
|
||
541 | * @param len the length of the packet in bytes
|
||
542 | *
|
||
543 | * @return the checksum of the packet, which will
|
||
544 | * become the last byte sent in the packet
|
||
545 | **/
|
||
546 | char xbee_compute_checksum(char* buf, int len) |
||
547 | { |
||
548 | int i;
|
||
549 | unsigned char sum = 0; |
||
550 | for (i = 0; i < len; i++) |
||
551 | sum += (unsigned char)buf[i]; |
||
552 | return 0xFF - sum; |
||
553 | } |
||
554 | |||
555 | /**
|
||
556 | * Adds header information and checksum to the given
|
||
557 | * packet and sends it. Header information includes
|
||
558 | * XBEE_FRAME_START and the packet length, as two bytes.
|
||
559 | *
|
||
560 | * @param buf the packet data
|
||
561 | * @param len the size in bytes of the packet data
|
||
562 | *
|
||
563 | **/
|
||
564 | static int xbee_send_frame(char* buf, int len) |
||
565 | { |
||
566 | char prefix[3]; |
||
567 | prefix[0] = XBEE_FRAME_START;
|
||
568 | prefix[1] = (len & 0xFF00) >> 8; |
||
569 | prefix[2] = len & 0xFF; |
||
570 | char checksum = xbee_compute_checksum(buf, len);
|
||
571 | |||
572 | if (xbee_send(prefix, 3) != 0) { |
||
573 | return -1; |
||
574 | } |
||
575 | |||
576 | if (xbee_send(buf, len) != 0) { |
||
577 | return -1; |
||
578 | } |
||
579 | |||
580 | if (xbee_send(&checksum, 1) != 0) { |
||
581 | return -1; |
||
582 | } |
||
583 | |||
584 | return 0; |
||
585 | } |
||
586 | |||
587 | /**
|
||
588 | * Resets the XBee Modem (including baud rate when on robot)
|
||
589 | *
|
||
590 | * Used for launching bootloader
|
||
591 | **/
|
||
592 | int xbee_reset(void) |
||
593 | { |
||
594 | #ifdef ROBOT
|
||
595 | xbee_send_modify_at_command("BD", "3"); |
||
596 | #endif
|
||
597 | xbee_send_read_at_command("FR");
|
||
598 | // delay 150 ms to wait for reset
|
||
599 | #ifndef ROBOT
|
||
600 | usleep(150000);
|
||
601 | #else
|
||
602 | _delay_ms(150);
|
||
603 | #endif
|
||
604 | |||
605 | return 0; |
||
606 | } |
||
607 | |||
608 | /**
|
||
609 | * Sends an AT command to read a parameter.
|
||
610 | *
|
||
611 | * @param command the AT command to send. For exmaple,
|
||
612 | * use ID to read the PAN ID and MY to return the XBee ID.
|
||
613 | * See the XBee reference guide for a complete listing.
|
||
614 | **/
|
||
615 | static int xbee_send_read_at_command(char* command) |
||
616 | { |
||
617 | return xbee_send_modify_at_command(command, NULL); |
||
618 | } |
||
619 | |||
620 | /**
|
||
621 | * Sends the given AT command.
|
||
622 | *
|
||
623 | * @param command the AT command to send (e.g., MY, ID)
|
||
624 | * @param value the value to pass as a parameter
|
||
625 | * (or NULL if there is no parameter)
|
||
626 | **/
|
||
627 | static int xbee_send_modify_at_command(char* command, char* value) |
||
628 | { |
||
629 | char buf[16]; |
||
630 | int i;
|
||
631 | |||
632 | buf[0] = XBEE_FRAME_AT_COMMAND;
|
||
633 | buf[1] = 1; |
||
634 | buf[2] = command[0]; |
||
635 | buf[3] = command[1]; |
||
636 | int valueLen = 0; |
||
637 | if (value != NULL) |
||
638 | { |
||
639 | valueLen = strlen(value); |
||
640 | if (valueLen > 8) |
||
641 | { |
||
642 | WL_DEBUG_PRINT("AT Command too large.\r\n");
|
||
643 | return -1; |
||
644 | } |
||
645 | |||
646 | for (i = 0; i < valueLen; i++) { |
||
647 | buf[4 + i] = value[i];
|
||
648 | } |
||
649 | } |
||
650 | |||
651 | return xbee_send_frame(buf, 4 + valueLen); |
||
652 | } |
||
653 | |||
654 | /**
|
||
655 | * Send the specified packet.
|
||
656 | *
|
||
657 | * @param packet the packet data to send
|
||
658 | * @param len the number of bytes in the packet
|
||
659 | *
|
||
660 | * @param dest the ID of the XBee to send the packet to,
|
||
661 | * or XBEE_BROADCAST to send the message to all robots
|
||
662 | * in the PAN.
|
||
663 | *
|
||
664 | * @param options a combination of the flags
|
||
665 | * XBEE_OPTIONS_NONE, XBEE_OPTIONS_DISABLE_RESPONSE and
|
||
666 | * XBEE_OPTIONS_BROADCAST_ALL_PANS
|
||
667 | *
|
||
668 | * @param frame the frame number to associate this packet
|
||
669 | * with. This will be used to identify the response when
|
||
670 | * the XBee alerts us as to whether or not our message
|
||
671 | * was received.
|
||
672 | **/
|
||
673 | int xbee_send_packet(char* packet, int len, int dest, char options, char frame) |
||
674 | { |
||
675 | char buf[5]; |
||
676 | char prefix[3]; |
||
677 | int i;
|
||
678 | unsigned char checksum = 0; |
||
679 | |||
680 | if (len > 100) |
||
681 | { |
||
682 | WL_DEBUG_PRINT("Packet is too large.\r\n");
|
||
683 | return -1; |
||
684 | } |
||
685 | |||
686 | //data for sending request
|
||
687 | buf[0] = XBEE_FRAME_TX_REQUEST_16;
|
||
688 | buf[1] = frame;
|
||
689 | buf[2] = (dest >> 8) & 0xFF; |
||
690 | buf[3] = dest & 0xFF; |
||
691 | buf[4] = options;
|
||
692 | |||
693 | //packet prefix, do this here so we don't need an extra buffer
|
||
694 | prefix[0] = XBEE_FRAME_START;
|
||
695 | prefix[1] = ((5 + len) & 0xFF00) >> 8; |
||
696 | prefix[2] = (5 + len) & 0xFF; |
||
697 | |||
698 | for (i = 0; i < 5; i++) |
||
699 | checksum += (unsigned char)buf[i]; |
||
700 | for (i = 0; i < len; i++) |
||
701 | checksum += (unsigned char)packet[i]; |
||
702 | checksum = 0xFF - checksum;
|
||
703 | |||
704 | if (xbee_send(prefix, 3) != 0) { |
||
705 | return -1; |
||
706 | } |
||
707 | |||
708 | if (xbee_send(buf, 5) != 0) { |
||
709 | return -1; |
||
710 | } |
||
711 | |||
712 | if (xbee_send(packet, len) != 0) { |
||
713 | return -1; |
||
714 | } |
||
715 | |||
716 | if (xbee_send((char*)&checksum, 1) != 0) { |
||
717 | return -1; |
||
718 | } |
||
719 | |||
720 | return 0; |
||
721 | } |
||
722 | |||
723 | /**
|
||
724 | * Reads a packet received from the XBee. This function
|
||
725 | * is non-blocking. The resulting packet is stored in dest.
|
||
726 | * Only returns transmission response packets and
|
||
727 | * received packets. The returned packet does not include
|
||
728 | * header information or the checksum. This method also
|
||
729 | * handles special packets dealt with by the XBee library,
|
||
730 | * and so should be called frequently while the XBee is in
|
||
731 | * use.<br><br>
|
||
732 | *
|
||
733 | * The first byte of the packet will be either
|
||
734 | * XBEE_TX_STATUS or XBEE_RX to indicated
|
||
735 | * a response to a sent message or a received message,
|
||
736 | * respectively.<br><br>
|
||
737 | *
|
||
738 | * For a status response packet:<br>
|
||
739 | * The first byte will be XBEE_TX_STATUS.<br>
|
||
740 | * The second byte will be the frame number.<br>
|
||
741 | * The third byte will be the result. 0 indicates success,
|
||
742 | * and nonzero indicates that an error ocurred in
|
||
743 | * transmitting the packet.<br><br>
|
||
744 | *
|
||
745 | * For a received packet:<br>
|
||
746 | * The first byte will be XBEE_RX.<br>
|
||
747 | * The second and third bytes will be the 16-bit
|
||
748 | * address of the packet's sender.<br>
|
||
749 | * The fourth byte is the signal strength.<br>
|
||
750 | * The fifth byte is 1 if the packet were sent to
|
||
751 | * a specific address, and 2 if it is a broadcast packet.<br><br>
|
||
752 | *
|
||
753 | * @param dest set to the packet data
|
||
754 | * @return the length of the packet, or -1 if no packet
|
||
755 | * is available
|
||
756 | **/
|
||
757 | int xbee_get_packet(unsigned char* dest) |
||
758 | { |
||
759 | int ret;
|
||
760 | //start reading a packet with XBEE_FRAME_START
|
||
761 | if (currentBufPos == 0) |
||
762 | { |
||
763 | do
|
||
764 | { |
||
765 | if (buffer_first == XBEE_BUFFER_SIZE)
|
||
766 | buffer_first = 0;
|
||
767 | // check if buffer is empty
|
||
768 | if (buffer_first == buffer_last) {
|
||
769 | return -1; |
||
770 | } |
||
771 | } while (arrival_buf[buffer_first++] != XBEE_FRAME_START);
|
||
772 | |||
773 | if (buffer_first == XBEE_BUFFER_SIZE) {
|
||
774 | buffer_first = 0;
|
||
775 | } |
||
776 | xbee_buf[0] = XBEE_FRAME_START;
|
||
777 | currentBufPos++; |
||
778 | } |
||
779 | |||
780 | int len = -1; |
||
781 | if (currentBufPos >= 3) { |
||
782 | len = (int)xbee_buf[2] + ((int)xbee_buf[1] << 8); |
||
783 | } |
||
784 | |||
785 | while (len == -1 //packet length has not been read yet |
||
786 | || currentBufPos < len + 4)
|
||
787 | { |
||
788 | if (currentBufPos == 3) |
||
789 | { |
||
790 | len = (int)xbee_buf[2] + ((int)xbee_buf[1] << 8); |
||
791 | if (len > 120) |
||
792 | { |
||
793 | WL_DEBUG_PRINT("Packet too large. Probably error in XBee transmission.\n");
|
||
794 | currentBufPos = 0;
|
||
795 | return -1; |
||
796 | } |
||
797 | } |
||
798 | |||
799 | // check if buffer is empty
|
||
800 | if (buffer_first == buffer_last) {
|
||
801 | return -1; |
||
802 | } |
||
803 | xbee_buf[currentBufPos++] = arrival_buf[buffer_first++]; |
||
804 | if (buffer_first == XBEE_BUFFER_SIZE) {
|
||
805 | buffer_first = 0;
|
||
806 | } |
||
807 | } |
||
808 | |||
809 | currentBufPos = 0;
|
||
810 | |||
811 | if (!xbee_verify_checksum(xbee_buf, len + 4)) |
||
812 | { |
||
813 | WL_DEBUG_PRINT("XBee checksum failed.\r\n");
|
||
814 | return -1; |
||
815 | } |
||
816 | |||
817 | //we will take care of the packet
|
||
818 | |||
819 | ret = xbee_handle_packet(xbee_buf+3, len);
|
||
820 | if (ret == 1) { |
||
821 | return 3; |
||
822 | } |
||
823 | |||
824 | if (dest == NULL) { |
||
825 | return -1; |
||
826 | } |
||
827 | |||
828 | int i;
|
||
829 | for (i = 3; i < len + 3; i++) { |
||
830 | dest[i - 3] = xbee_buf[i];
|
||
831 | } |
||
832 | return len;
|
||
833 | } |
||
834 | |||
835 | /**
|
||
836 | * Handles modem status packets.
|
||
837 | *
|
||
838 | * @param status the type of status packet received.
|
||
839 | **/
|
||
840 | void xbee_handle_status(char status) |
||
841 | { |
||
842 | switch (status)
|
||
843 | { |
||
844 | case 0: |
||
845 | WL_DEBUG_PRINT("XBee hardware reset.\r\n");
|
||
846 | break;
|
||
847 | case 1: |
||
848 | WL_DEBUG_PRINT("Watchdog timer reset.\r\n");
|
||
849 | break;
|
||
850 | case 2: |
||
851 | WL_DEBUG_PRINT("Associated.\r\n");
|
||
852 | break;
|
||
853 | case 3: |
||
854 | WL_DEBUG_PRINT("Disassociated.\r\n");
|
||
855 | break;
|
||
856 | case 4: |
||
857 | WL_DEBUG_PRINT("Synchronization lost.\r\n");
|
||
858 | break;
|
||
859 | case 5: |
||
860 | WL_DEBUG_PRINT("Coordinator realignment.\r\n");
|
||
861 | break;
|
||
862 | case 6: |
||
863 | WL_DEBUG_PRINT("Coordinator started.\r\n");
|
||
864 | break;
|
||
865 | } |
||
866 | } |
||
867 | |||
868 | /**
|
||
869 | * Handles AT command response packets.
|
||
870 | * @param command the two character AT command, e.g. MY or ID
|
||
871 | * @param result 0 for success, 1 for an error
|
||
872 | * @param extra the hex value of the requested register
|
||
873 | * @param extraLen the length in bytes of extra
|
||
874 | **/
|
||
875 | static void xbee_handle_at_command_response(char* command, char result, char* extra, int extraLen) |
||
876 | { |
||
877 | if (result == 1) |
||
878 | { |
||
879 | WL_DEBUG_PRINT("Error with AT");
|
||
880 | WL_DEBUG_PRINT(command); |
||
881 | WL_DEBUG_PRINT(" packet.\r\n");
|
||
882 | } |
||
883 | WL_DEBUG_PRINT("AT");
|
||
884 | WL_DEBUG_PRINT(command); |
||
885 | WL_DEBUG_PRINT(" command was successful.\r\n");
|
||
886 | |||
887 | if (command[0] == 'I' && command[1] == 'D') |
||
888 | { |
||
889 | xbee_panID = xbee_pending_panID; |
||
890 | WL_DEBUG_PRINT("PAN ID set to ");
|
||
891 | WL_DEBUG_PRINT_INT(xbee_panID); |
||
892 | WL_DEBUG_PRINT(".\r\n");
|
||
893 | return;
|
||
894 | } |
||
895 | |||
896 | if (command[0] == 'C' && command[1] == 'H') |
||
897 | { |
||
898 | xbee_channel = xbee_pending_channel; |
||
899 | WL_DEBUG_PRINT("Channel set to ");
|
||
900 | WL_DEBUG_PRINT_INT(xbee_channel); |
||
901 | WL_DEBUG_PRINT(".\r\n");
|
||
902 | return;
|
||
903 | } |
||
904 | |||
905 | if (command[0] == 'M' && command[1] == 'Y' && extraLen != 0) |
||
906 | { |
||
907 | xbee_address = 0;
|
||
908 | int i;
|
||
909 | for (i = 0; i < extraLen; i++) { |
||
910 | xbee_address = (xbee_address << 8) + extra[i];
|
||
911 | } |
||
912 | |||
913 | WL_DEBUG_PRINT("XBee address is ");
|
||
914 | WL_DEBUG_PRINT_INT(xbee_address); |
||
915 | WL_DEBUG_PRINT(".\r\n");
|
||
916 | |||
917 | if (xbee_address == 0) |
||
918 | { |
||
919 | WL_DEBUG_PRINT("XBee 16-bit address must be set using ATMY.\r\n");
|
||
920 | #ifndef ROBOT
|
||
921 | exit(0);
|
||
922 | #endif
|
||
923 | } |
||
924 | } |
||
925 | } |
||
926 | |||
927 | /**
|
||
928 | * Attempts to handle the packet if it is dealt with
|
||
929 | * by the library.
|
||
930 | * We will handle the following packet types:
|
||
931 | * Modem Status
|
||
932 | * AT Command Response
|
||
933 | *
|
||
934 | * @param packet the packet to handle
|
||
935 | * @param len the length of the packet
|
||
936 | *
|
||
937 | * @return 1 if we have handled the packet, 0 otherwise
|
||
938 | */
|
||
939 | static int xbee_handle_packet(char* packet, int len) |
||
940 | { |
||
941 | |||
942 | char command[3] = {1, 2, 3}; |
||
943 | if (len <= 0) //this should not happend |
||
944 | { |
||
945 | WL_DEBUG_PRINT("Non-positive packet length.\r\n");
|
||
946 | return 0; |
||
947 | } |
||
948 | |||
949 | switch ((unsigned char)packet[0]) //packet type |
||
950 | { |
||
951 | case XBEE_FRAME_STATUS:
|
||
952 | xbee_handle_status(packet[1]);
|
||
953 | return 1; |
||
954 | case XBEE_FRAME_AT_COMMAND_RESPONSE:
|
||
955 | command[0] = packet[2]; |
||
956 | command[1] = packet[3]; |
||
957 | command[2] = 0; |
||
958 | xbee_handle_at_command_response(command, packet[4], packet + 5, len - 5); |
||
959 | return 1; |
||
960 | } |
||
961 | return 0; |
||
962 | } |
||
963 | |||
964 | /**
|
||
965 | * Sets the personal area network id.
|
||
966 | *
|
||
967 | * @param id the new personal area network (PAN) id
|
||
968 | **/
|
||
969 | int xbee_set_pan_id(int id) |
||
970 | { |
||
971 | char s[3]; |
||
972 | s[0] = (id >> 8) & 0xFF; |
||
973 | s[1] = id & 0xFF; |
||
974 | s[2] = 0; |
||
975 | xbee_pending_panID = id; |
||
976 | return xbee_send_modify_at_command("ID", s); |
||
977 | } |
||
978 | |||
979 | /**
|
||
980 | * Get the PAN ID for the XBee.
|
||
981 | *
|
||
982 | * @return the personal area network id, or
|
||
983 | * XBEE_PAN_DEFAULT if it has not yet been set.
|
||
984 | **/
|
||
985 | unsigned int xbee_get_pan_id() |
||
986 | { |
||
987 | return xbee_panID;
|
||
988 | } |
||
989 | |||
990 | /**
|
||
991 | * Set the channel the XBee is using.
|
||
992 | *
|
||
993 | * @param channel the channel the XBee will not use,
|
||
994 | * between 0x0B and 0x1A
|
||
995 | *
|
||
996 | * @see xbee_get_channel
|
||
997 | **/
|
||
998 | int xbee_set_channel(int channel) |
||
999 | { |
||
1000 | if (channel < 0x0B || channel > 0x1A) |
||
1001 | { |
||
1002 | WL_DEBUG_PRINT("Channel out of range.\r\n");
|
||
1003 | return -1; |
||
1004 | } |
||
1005 | |||
1006 | char s[3]; |
||
1007 | s[0] = channel & 0xFF; |
||
1008 | s[1] = 0; |
||
1009 | xbee_pending_channel = channel; |
||
1010 | |||
1011 | return xbee_send_modify_at_command("CH", s); |
||
1012 | } |
||
1013 | |||
1014 | /**
|
||
1015 | * Returns the channel which the XBee is currently using.
|
||
1016 | *
|
||
1017 | * @return the channel the XBee is using
|
||
1018 | *
|
||
1019 | * @see xbee_set_channel
|
||
1020 | **/
|
||
1021 | int xbee_get_channel(void) |
||
1022 | { |
||
1023 | return xbee_channel;
|
||
1024 | } |
||
1025 | |||
1026 | /**
|
||
1027 | * Get the 16-bit address of the XBee.
|
||
1028 | * This is used to specify who to send messages to
|
||
1029 | * and who messages are from.
|
||
1030 | *
|
||
1031 | * @return the 16-bit address of the XBee.
|
||
1032 | **/
|
||
1033 | unsigned int xbee_get_address() |
||
1034 | { |
||
1035 | return xbee_address;
|
||
1036 | } |
||
1037 | |||
1038 | #ifndef ROBOT
|
||
1039 | void xbee_set_com_port(char* port) |
||
1040 | { |
||
1041 | xbee_com_port = port; |
||
1042 | } |
||
1043 | #endif |