root / trunk / code / projects / libwireless / lib / xbee.c @ 717
History | View | Annotate | Download (24.3 KB)
1 |
/**
|
---|---|
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 |
|
46 |
#else
|
47 |
|
48 |
#include <serial.h> |
49 |
#include <avr/interrupt.h> |
50 |
|
51 |
#endif
|
52 |
|
53 |
#include <stdio.h> |
54 |
#include <stdlib.h> |
55 |
#include <string.h> |
56 |
|
57 |
#define XBEE_FRAME_START 0x7E |
58 |
#define XBEE_GET_PACKET_TIMEOUT 1000 |
59 |
|
60 |
/*Frame Types*/
|
61 |
#define XBEE_FRAME_STATUS 0x8A |
62 |
#define XBEE_FRAME_AT_COMMAND 0x08 |
63 |
#define XBEE_FRAME_AT_COMMAND_RESPONSE 0x88 |
64 |
#define XBEE_FRAME_TX_REQUEST_64 0x00 |
65 |
#define XBEE_FRAME_TX_REQUEST_16 0x01 |
66 |
#define XBEE_FRAME_TX_STATUS XBEE_TX_STATUS
|
67 |
#define XBEE_FRAME_RX_64 0x80 |
68 |
#define XBEE_FRAME_RX_16 XBEE_RX
|
69 |
|
70 |
/*Internal Function Prototypes*/
|
71 |
|
72 |
/*I/O Functions*/
|
73 |
static int xbee_send(char* buf, int size); |
74 |
static int xbee_send_string(char* c); |
75 |
|
76 |
#ifndef ROBOT
|
77 |
static int xbee_read(char* buf, int size); |
78 |
#endif
|
79 |
|
80 |
/*Command Mode Functions
|
81 |
* Called during initialization.
|
82 |
*/
|
83 |
static int xbee_enter_command_mode(void); |
84 |
static int xbee_exit_command_mode(void); |
85 |
static int xbee_enter_api_mode(void); |
86 |
static int xbee_exit_api_mode(void); |
87 |
static int xbee_wait_for_string(char* s, int len); |
88 |
static int xbee_wait_for_ok(void); |
89 |
|
90 |
/*API Mode Functions*/
|
91 |
|
92 |
static int xbee_handle_packet(char* packet, int len); |
93 |
static void xbee_handle_at_command_response(char* command, char result, char* extra, int extraLen); |
94 |
static void xbee_handle_status(char status); |
95 |
static int xbee_verify_checksum(char* packet, int len); |
96 |
static char xbee_compute_checksum(char* packet, int len); |
97 |
static int xbee_send_frame(char* buf, int len); |
98 |
static int xbee_send_read_at_command(char* command); |
99 |
static int xbee_send_modify_at_command(char* command, char* value); |
100 |
|
101 |
/*Global Variables*/
|
102 |
|
103 |
#ifndef ROBOT
|
104 |
static char* xbee_com_port = XBEE_PORT_DEFAULT; |
105 |
static int xbee_stream; |
106 |
static pthread_t* xbee_listen_thread;
|
107 |
#endif
|
108 |
|
109 |
// TODO: is this a good size?
|
110 |
//TODO: does this buffer size need to be so large? we have constrained memory, so this should be as small as feasibly possible
|
111 |
#define XBEE_BUFFER_SIZE 256 |
112 |
// a buffer for data received from the XBee
|
113 |
char arrival_buf[XBEE_BUFFER_SIZE];
|
114 |
// location of last unread byte in buffer
|
115 |
volatile int buffer_last = 0; |
116 |
// first unread byte in buffer
|
117 |
volatile int buffer_first = 0; |
118 |
|
119 |
|
120 |
//used to store packets as they are read
|
121 |
|
122 |
//TODO: does this need to be 128? can it be smaller to save memory?
|
123 |
//TODO: this shouldn't be hardcoded as 128. it should be a define.
|
124 |
static char xbee_buf[128]; |
125 |
static int currentBufPos = 0; |
126 |
|
127 |
//XBee status
|
128 |
static unsigned int xbee_panID = XBEE_PAN_DEFAULT; |
129 |
static unsigned int xbee_pending_panID = XBEE_PAN_DEFAULT; |
130 |
static int xbee_channel = XBEE_CHANNEL_DEFAULT; |
131 |
static int xbee_pending_channel = XBEE_CHANNEL_DEFAULT; |
132 |
static volatile unsigned int xbee_address = 0; |
133 |
|
134 |
//TODO: this is only needed for the computer side, right? I'm going to put #ifndef ROBOT around it to remove it from robot code
|
135 |
#ifndef ROBOT
|
136 |
void printHex(char * s, int len) { |
137 |
int i;
|
138 |
for (i = 0; i < len; i++) { |
139 |
printf("0x%x ", (int)(s[i])); |
140 |
} |
141 |
printf("\n");
|
142 |
} |
143 |
#endif
|
144 |
|
145 |
|
146 |
/*Function Implementations*/
|
147 |
|
148 |
#ifdef ROBOT
|
149 |
|
150 |
/**
|
151 |
* Interrupt for the robot. Adds bytes received from the xbee
|
152 |
* to the buffer.
|
153 |
**/
|
154 |
#ifndef FIREFLY
|
155 |
ISR(USART1_RX_vect) |
156 |
{ |
157 |
char c = UDR1;
|
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 |
#else
|
169 |
SIGNAL(SIG_USART0_RECV) |
170 |
{ |
171 |
char c = UDR0;
|
172 |
arrival_buf[buffer_last] = c; |
173 |
int t = buffer_last + 1; |
174 |
if (t == XBEE_BUFFER_SIZE)
|
175 |
t = 0;
|
176 |
if (t == buffer_first)
|
177 |
{ |
178 |
WL_DEBUG_PRINT("Out of space in buffer.\n");
|
179 |
} |
180 |
buffer_last = t; |
181 |
} |
182 |
#endif
|
183 |
|
184 |
#else
|
185 |
|
186 |
// Computer code
|
187 |
|
188 |
/**
|
189 |
* Thread that listens to the xbee.
|
190 |
**/
|
191 |
static void* listen_to_xbee(void* x) |
192 |
{ |
193 |
char c;
|
194 |
while (1) |
195 |
{ |
196 |
if (xbee_read(&c, 1) != 0) { |
197 |
fprintf(stderr, "xbee_read failed.\n");
|
198 |
return NULL; |
199 |
} |
200 |
|
201 |
//DEBUGGING PRINT
|
202 |
//printf("interrupt: %c (%d)\n", c, (int)c);
|
203 |
arrival_buf[buffer_last] = c; |
204 |
int t = buffer_last + 1; |
205 |
if (t == XBEE_BUFFER_SIZE)
|
206 |
t = 0;
|
207 |
if (t == buffer_first)
|
208 |
{ |
209 |
WL_DEBUG_PRINT("Out of space in buffer.\n");
|
210 |
} |
211 |
buffer_last = t; |
212 |
|
213 |
usleep(1000);
|
214 |
} |
215 |
|
216 |
return NULL; |
217 |
} |
218 |
|
219 |
#endif
|
220 |
|
221 |
/**
|
222 |
* Initializes the XBee library so that other functions may be used.
|
223 |
**/
|
224 |
int xbee_lib_init()
|
225 |
{ |
226 |
arrival_buf[0] = 'A'; |
227 |
arrival_buf[1] = 'A'; |
228 |
arrival_buf[2] = 'A'; |
229 |
#ifdef ROBOT
|
230 |
|
231 |
//enable the receiving interrupt
|
232 |
#ifdef FIREFLY
|
233 |
UCSR0B |= _BV(RXCIE) | _BV(RXEN); |
234 |
#else
|
235 |
UCSR1B |= _BV(RXCIE); |
236 |
#endif
|
237 |
sei(); |
238 |
#else
|
239 |
printf("Connecting to port %s.\n", xbee_com_port);
|
240 |
xbee_stream = open(xbee_com_port, O_RDWR); |
241 |
if (xbee_stream == -1/* || lockf(xbee_stream, F_TEST, 0) != 0*/) |
242 |
{ |
243 |
printf("Failed to open connection to XBee on port %s\r\n", xbee_com_port);
|
244 |
return -1; |
245 |
} else {
|
246 |
printf("Successfully opened connection to XBee on port %s\r\n", xbee_com_port);
|
247 |
} |
248 |
|
249 |
// set baud rate, etc. correctly
|
250 |
struct termios options;
|
251 |
|
252 |
tcgetattr(xbee_stream, &options); |
253 |
cfsetispeed(&options, B9600); |
254 |
cfsetospeed(&options, B9600); |
255 |
options.c_iflag &= ~ICRNL; |
256 |
options.c_oflag &= ~OCRNL; |
257 |
options.c_cflag |= (CLOCAL | CREAD); |
258 |
options.c_cflag &= ~PARENB; |
259 |
options.c_cflag &= ~CSTOPB; |
260 |
options.c_cflag &= ~CSIZE; |
261 |
options.c_cflag |= CS8; |
262 |
options.c_lflag &= ~ICANON; |
263 |
options.c_cc[VMIN] = 1;
|
264 |
options.c_cc[VTIME] = 50;
|
265 |
|
266 |
if (tcsetattr(xbee_stream, TCSANOW, &options))
|
267 |
{ |
268 |
fprintf(stderr, "Error setting attributes.\n");
|
269 |
return -1; |
270 |
} else {
|
271 |
//printf("Successfully set termios attributes.\n");
|
272 |
} |
273 |
|
274 |
//lockf(xbee_stream, F_LOCK, 0);
|
275 |
|
276 |
xbee_listen_thread = (pthread_t*)malloc(sizeof(pthread_t));
|
277 |
if (xbee_listen_thread == NULL) |
278 |
{ |
279 |
fprintf(stderr, "%s: Malloc failed.\n", __FUNCTION__);
|
280 |
return -1; |
281 |
} |
282 |
|
283 |
int ret = pthread_create(xbee_listen_thread, NULL, listen_to_xbee, NULL); |
284 |
if (ret)
|
285 |
{ |
286 |
fprintf(stderr, "Failed to create listener thread.\r\n");
|
287 |
return -1; |
288 |
} else {
|
289 |
//printf("Successfully created listener thread.\n");
|
290 |
} |
291 |
#endif
|
292 |
|
293 |
//DEBUGGING PRINT
|
294 |
//printf("about to call xbee_enter_command_mode\n");
|
295 |
|
296 |
if (xbee_enter_command_mode() != 0) { |
297 |
#ifndef ROBOT
|
298 |
printf("Error returned from xbee_enter_command_mode\n");
|
299 |
#endif
|
300 |
return -1; |
301 |
} |
302 |
|
303 |
//DEBUGGING PRINT
|
304 |
//printf("about to call xbee_enter_api_mode\n");
|
305 |
|
306 |
if (xbee_enter_api_mode() != 0) { |
307 |
#ifndef ROBOT
|
308 |
printf("Error returned from xbee_enter_api_mode\n");
|
309 |
#endif
|
310 |
return -1; |
311 |
} |
312 |
|
313 |
//DEBUGGING PRINT
|
314 |
//printf("about to call xbee_exit_command_mode\n");
|
315 |
|
316 |
if (xbee_exit_command_mode() != 0) { |
317 |
#ifndef ROBOT
|
318 |
printf("Error returned from xbee_exit_command_mode\n");
|
319 |
#endif
|
320 |
return -1; |
321 |
} |
322 |
|
323 |
//DEBUGGING PRINT
|
324 |
//printf("about to call xbee_send_read_at_command\n");
|
325 |
|
326 |
if (xbee_send_read_at_command("MY")) { |
327 |
#ifndef ROBOT
|
328 |
printf("Error returned from xbee_send_read_at_command\n");
|
329 |
#endif
|
330 |
return -1; |
331 |
} |
332 |
|
333 |
#ifndef ROBOT
|
334 |
//printf("About to enter while loop to get xbee_address.\n");
|
335 |
int i;
|
336 |
for (i = 0; xbee_address == 0 && i < XBEE_GET_PACKET_TIMEOUT; i++) { |
337 |
ret = xbee_get_packet(NULL);
|
338 |
|
339 |
usleep(1000);
|
340 |
|
341 |
if (ret == -1) { |
342 |
printf("xbee_get_packet(NULL) failed.\n");
|
343 |
return -1; |
344 |
} |
345 |
} |
346 |
|
347 |
// printf("After exiting while loop to get xbee_address.\n");
|
348 |
#else
|
349 |
//wait to return until the address is set
|
350 |
//TODO: this shouldn't wait indefinitely. There should be some sort of reasonable timeout
|
351 |
// so if the address is never set right, an error can be returned instead of having the
|
352 |
// robot hang forever
|
353 |
while (xbee_address == 0) { |
354 |
xbee_get_packet(NULL);
|
355 |
} |
356 |
#endif
|
357 |
|
358 |
#ifndef ROBOT
|
359 |
if (i == XBEE_GET_PACKET_TIMEOUT) { // We timed-out. |
360 |
|
361 |
printf("xbee_get_packet timed out.\n");
|
362 |
return -1; |
363 |
} else {
|
364 |
return 0; |
365 |
} |
366 |
#else
|
367 |
return 0; |
368 |
#endif
|
369 |
} |
370 |
|
371 |
/**
|
372 |
* Call when finished using the XBee library. This releases
|
373 |
* all sued resources.
|
374 |
**/
|
375 |
void xbee_terminate()
|
376 |
{ |
377 |
#ifndef ROBOT
|
378 |
pthread_cancel(*xbee_listen_thread); |
379 |
free(xbee_listen_thread); |
380 |
lockf(xbee_stream, F_ULOCK, 0);
|
381 |
close(xbee_stream); |
382 |
#endif
|
383 |
} |
384 |
|
385 |
/**
|
386 |
* Send a buffer buf of size bytes to the XBee.
|
387 |
*
|
388 |
* @param buf the buffer of data to send
|
389 |
* @param size the number of bytes to send
|
390 |
**/
|
391 |
static int xbee_send(char* buf, int size) |
392 |
{ |
393 |
#ifdef ROBOT
|
394 |
int i;
|
395 |
for (i = 0; i < size; i++) { |
396 |
xbee_putc(buf[i]); |
397 |
} |
398 |
|
399 |
return 0; |
400 |
|
401 |
#else
|
402 |
//DEBUGGING PRINT
|
403 |
//printf("in xbee_send ");
|
404 |
//printHex(buf, size);
|
405 |
|
406 |
int ret = write(xbee_stream, buf, size);
|
407 |
//success
|
408 |
if (ret == size)
|
409 |
return 0; |
410 |
if (ret == -1) |
411 |
{ |
412 |
//interrupted by system signal, probably timer interrupt.
|
413 |
//just try again
|
414 |
if (errno == 4) |
415 |
{ |
416 |
return xbee_send(buf, size);
|
417 |
} |
418 |
printf("Failed to write to xbee, error %i.\r\n", errno);
|
419 |
return -1; |
420 |
} |
421 |
|
422 |
//write was interrupted after writing ret bytes
|
423 |
return xbee_send(buf + ret, size - ret);
|
424 |
#endif
|
425 |
} |
426 |
|
427 |
/**
|
428 |
* Sends a string to the XBee.
|
429 |
*
|
430 |
* @param c the string to send to the XBEE
|
431 |
**/
|
432 |
//TODO: this function is so simple, it *may* be beneficial to inline this function. testing of if
|
433 |
// it reduces code size or not should be done to be sure.
|
434 |
static int xbee_send_string(char* c) |
435 |
{ |
436 |
return xbee_send(c, strlen(c));
|
437 |
} |
438 |
|
439 |
#ifndef ROBOT
|
440 |
static int xbee_read(char* buf, int size) |
441 |
{ |
442 |
if (read(xbee_stream, buf, size) == -1) { |
443 |
printf("Failed to read from xbee.\r\n");
|
444 |
return -1; |
445 |
} |
446 |
|
447 |
return 0; |
448 |
} |
449 |
#endif
|
450 |
|
451 |
/**
|
452 |
* Enter into command mode.
|
453 |
**/
|
454 |
static int xbee_enter_command_mode() |
455 |
{ |
456 |
if (xbee_send_string("+++") != 0) { |
457 |
return -1; |
458 |
} |
459 |
|
460 |
#ifndef ROBOT
|
461 |
// printf("In xbee_enter_command_mode about to call xbee_wait_for_ok()\n");
|
462 |
#endif
|
463 |
|
464 |
if (xbee_wait_for_ok() != 0) { |
465 |
#ifndef ROBOT
|
466 |
printf("xbee_wait_for_ok failed.\n");
|
467 |
#endif
|
468 |
return -1; |
469 |
} else {
|
470 |
return 0; |
471 |
} |
472 |
} |
473 |
|
474 |
/**
|
475 |
* Exit from command mode.
|
476 |
**/
|
477 |
static int xbee_exit_command_mode() |
478 |
{ |
479 |
if (xbee_send_string("ATCN\r") != 0) { |
480 |
return -1; |
481 |
} |
482 |
|
483 |
xbee_wait_for_ok(); |
484 |
|
485 |
return 0; |
486 |
} |
487 |
|
488 |
/**
|
489 |
* Enter API mode.
|
490 |
**/
|
491 |
static int xbee_enter_api_mode() |
492 |
{ |
493 |
if (xbee_send_string("ATAP 1\r") != 0) { |
494 |
return -1; |
495 |
} |
496 |
xbee_wait_for_ok(); |
497 |
|
498 |
return 0; |
499 |
} |
500 |
|
501 |
/**
|
502 |
* Exit API mode. (warning - does not check for response)
|
503 |
**/
|
504 |
//TODO: this function is so simple, it *may* be beneficial to inline this function. testing of if
|
505 |
// it reduces code size or not should be done to be sure.
|
506 |
static int xbee_exit_api_mode() |
507 |
{ |
508 |
return xbee_send_string("ATAP 0\r"); |
509 |
} |
510 |
|
511 |
/**
|
512 |
* Wait until the string "OK\r" is received from the XBee.
|
513 |
**/
|
514 |
//TODO: this function is so simple, it *may* be beneficial to inline this function. testing of if
|
515 |
// it reduces code size or not should be done to be sure.
|
516 |
static int xbee_wait_for_ok() |
517 |
{ |
518 |
//DEBUGGING PRINT
|
519 |
//printf("\tin xbee_wait_for_ok\n");
|
520 |
return xbee_wait_for_string("OK\r", 3); |
521 |
} |
522 |
|
523 |
/**
|
524 |
* Delay until the specified string is received from
|
525 |
* the XBee. Discards all other XBee data.
|
526 |
*
|
527 |
* @param s the string to receive
|
528 |
* @param len the length of the string
|
529 |
**/
|
530 |
static int xbee_wait_for_string(char* s, int len) |
531 |
{ |
532 |
//DEBUGGING PRINT
|
533 |
//printf("\t in xbee_wait_for_string\n");
|
534 |
|
535 |
#ifndef ROBOT
|
536 |
//printf("In xbee_wait_for_string.\n");
|
537 |
#endif
|
538 |
|
539 |
char* curr = s;
|
540 |
while (curr - s < len) {
|
541 |
// check if buffer is empty
|
542 |
if (buffer_last != buffer_first) {
|
543 |
char c = arrival_buf[buffer_first++];
|
544 |
if (buffer_first == XBEE_BUFFER_SIZE) {
|
545 |
buffer_first = 0;
|
546 |
} |
547 |
|
548 |
//DEBUGGING PRINT
|
549 |
//printf("\t\t c is %c (%d)\n", c, (int)c);
|
550 |
|
551 |
if (c == *curr) {
|
552 |
curr++; |
553 |
} else {
|
554 |
#ifndef ROBOT
|
555 |
//return -1; // Computer is less forgiving.
|
556 |
curr = s; |
557 |
#else
|
558 |
curr = s; |
559 |
#endif
|
560 |
} |
561 |
} // else buffer is empty.
|
562 |
|
563 |
#ifndef ROBOT
|
564 |
usleep(100);
|
565 |
#endif
|
566 |
} |
567 |
|
568 |
return 0; |
569 |
} |
570 |
|
571 |
/**
|
572 |
* Verifies that the packets checksum is correct.
|
573 |
* (If the checksum is correct, the sum of the bytes
|
574 |
* is 0xFF.)
|
575 |
*
|
576 |
* @param packet the packet received. This includes the first
|
577 |
* three bytes, which are header information from the XBee.
|
578 |
*
|
579 |
* @param len The length of the packet received from the XBee
|
580 |
*
|
581 |
* @return 0 if the checksum is incorrect, nonzero
|
582 |
* otherwise
|
583 |
**/
|
584 |
int xbee_verify_checksum(char* packet, int len) |
585 |
{ |
586 |
unsigned char sum = 0; |
587 |
int i;
|
588 |
for (i = 3; i < len; i++) |
589 |
sum += (unsigned char)packet[i]; |
590 |
return sum == 0xFF; |
591 |
} |
592 |
|
593 |
/**
|
594 |
* Returns the checksum of the given packet.
|
595 |
*
|
596 |
* @param buf the data for the packet to send
|
597 |
* @param len the length of the packet in bytes
|
598 |
*
|
599 |
* @return the checksum of the packet, which will
|
600 |
* become the last byte sent in the packet
|
601 |
**/
|
602 |
char xbee_compute_checksum(char* buf, int len) |
603 |
{ |
604 |
int i;
|
605 |
unsigned char sum = 0; |
606 |
for (i = 0; i < len; i++) |
607 |
sum += (unsigned char)buf[i]; |
608 |
return 0xFF - sum; |
609 |
} |
610 |
|
611 |
/**
|
612 |
* Adds header information and checksum to the given
|
613 |
* packet and sends it. Header information includes
|
614 |
* XBEE_FRAME_START and the packet length, as two bytes.
|
615 |
*
|
616 |
* @param buf the packet data
|
617 |
* @param len the size in bytes of the packet data
|
618 |
*
|
619 |
**/
|
620 |
static int xbee_send_frame(char* buf, int len) |
621 |
{ |
622 |
printf("in %s and len is %d\n", __FUNCTION__, len);
|
623 |
|
624 |
char prefix[3]; |
625 |
prefix[0] = XBEE_FRAME_START;
|
626 |
prefix[1] = (len & 0xFF00) >> 8; |
627 |
prefix[2] = len & 0xFF; |
628 |
char checksum = xbee_compute_checksum(buf, len);
|
629 |
|
630 |
if (xbee_send(prefix, 3) != 0) { |
631 |
return -1; |
632 |
} |
633 |
|
634 |
if (xbee_send(buf, len) != 0) { |
635 |
return -1; |
636 |
} |
637 |
|
638 |
if (xbee_send(&checksum, 1) != 0) { |
639 |
return -1; |
640 |
} |
641 |
|
642 |
return 0; |
643 |
} |
644 |
|
645 |
/**
|
646 |
* Sends an AT command to read a parameter.
|
647 |
*
|
648 |
* @param command the AT command to send. For exmaple,
|
649 |
* use ID to read the PAN ID and MY to return the XBee ID.
|
650 |
* See the XBee reference guide for a complete listing.
|
651 |
**/
|
652 |
//TODO: this function is so simple, it *may* be beneficial to inline this function. testing of if
|
653 |
// it reduces code size or not should be done to be sure.
|
654 |
static int xbee_send_read_at_command(char* command) |
655 |
{ |
656 |
return xbee_send_modify_at_command(command, NULL); |
657 |
} |
658 |
|
659 |
/**
|
660 |
* Sends the given AT command.
|
661 |
*
|
662 |
* @param command the AT command to send (e.g., MY, ID)
|
663 |
* @param value the value to pass as a parameter
|
664 |
* (or NULL if there is no parameter)
|
665 |
**/
|
666 |
static int xbee_send_modify_at_command(char* command, char* value) |
667 |
{ |
668 |
printf("in %s with command %s and value %s\n", __FUNCTION__, command, value);
|
669 |
|
670 |
char buf[16]; |
671 |
int i;
|
672 |
|
673 |
buf[0] = XBEE_FRAME_AT_COMMAND;
|
674 |
buf[1] = 1; |
675 |
buf[2] = command[0]; |
676 |
buf[3] = command[1]; |
677 |
int valueLen = 0; |
678 |
if (value != NULL) |
679 |
{ |
680 |
valueLen = strlen(value); |
681 |
if (valueLen > 8) |
682 |
{ |
683 |
WL_DEBUG_PRINT("AT Command too large.\r\n");
|
684 |
return -1; |
685 |
} |
686 |
|
687 |
for (i = 0; i < valueLen; i++) { |
688 |
buf[4 + i] = value[i];
|
689 |
} |
690 |
} |
691 |
|
692 |
return xbee_send_frame(buf, 4 + valueLen); |
693 |
} |
694 |
|
695 |
/**
|
696 |
* Send the specified packet.
|
697 |
*
|
698 |
* @param packet the packet data to send
|
699 |
* @param len the number of bytes in the packet
|
700 |
*
|
701 |
* @param dest the ID of the XBee to send the packet to,
|
702 |
* or XBEE_BROADCAST to send the message to all robots
|
703 |
* in the PAN.
|
704 |
*
|
705 |
* @param options a combination of the flags
|
706 |
* XBEE_OPTIONS_NONE, XBEE_OPTIONS_DISABLE_RESPONSE and
|
707 |
* XBEE_OPTIONS_BROADCAST_ALL_PANS
|
708 |
*
|
709 |
* @param frame the frame number to associate this packet
|
710 |
* with. This will be used to identify the response when
|
711 |
* the XBee alerts us as to whether or not our message
|
712 |
* was received.
|
713 |
**/
|
714 |
int xbee_send_packet(char* packet, int len, int dest, char options, char frame) |
715 |
{ |
716 |
char buf[5]; |
717 |
char prefix[3]; |
718 |
int i;
|
719 |
unsigned char checksum = 0; |
720 |
|
721 |
if (len > 100) |
722 |
{ |
723 |
WL_DEBUG_PRINT("Packet is too large.\r\n");
|
724 |
return -1; |
725 |
} |
726 |
|
727 |
//data for sending request
|
728 |
buf[0] = XBEE_FRAME_TX_REQUEST_16;
|
729 |
buf[1] = frame;
|
730 |
buf[2] = (dest >> 8) & 0xFF; |
731 |
buf[3] = dest & 0xFF; |
732 |
buf[4] = options;
|
733 |
|
734 |
//packet prefix, do this here so we don't need an extra buffer
|
735 |
prefix[0] = XBEE_FRAME_START;
|
736 |
prefix[1] = ((5 + len) & 0xFF00) >> 8; |
737 |
prefix[2] = (5 + len) & 0xFF; |
738 |
|
739 |
for (i = 0; i < 5; i++) |
740 |
checksum += (unsigned char)buf[i]; |
741 |
for (i = 0; i < len; i++) |
742 |
checksum += (unsigned char)packet[i]; |
743 |
checksum = 0xFF - checksum;
|
744 |
|
745 |
if (xbee_send(prefix, 3) != 0) { |
746 |
return -1; |
747 |
} |
748 |
|
749 |
if (xbee_send(buf, 5) != 0) { |
750 |
return -1; |
751 |
} |
752 |
|
753 |
if (xbee_send(packet, len) != 0) { |
754 |
return -1; |
755 |
} |
756 |
|
757 |
if (xbee_send((char*)&checksum, 1) != 0) { |
758 |
return -1; |
759 |
} |
760 |
|
761 |
return 0; |
762 |
} |
763 |
|
764 |
/**
|
765 |
* Reads a packet received from the XBee. This function
|
766 |
* is non-blocking. The resulting packet is stored in dest.
|
767 |
* Only returns transmission response packets and
|
768 |
* received packets. The returned packet does not include
|
769 |
* header information or the checksum. This method also
|
770 |
* handles special packets dealt with by the XBee library,
|
771 |
* and so should be called frequently while the XBee is in
|
772 |
* use.<br><br>
|
773 |
*
|
774 |
* The first byte of the packet will be either
|
775 |
* XBEE_TX_STATUS or XBEE_RX to indicated
|
776 |
* a response to a sent message or a received message,
|
777 |
* respectively.<br><br>
|
778 |
*
|
779 |
* For a status response packet:<br>
|
780 |
* The first byte will be XBEE_TX_STATUS.<br>
|
781 |
* The second byte will be the frame number.<br>
|
782 |
* The third byte will be the result. 0 indicates success,
|
783 |
* and nonzero indicates that an error ocurred in
|
784 |
* transmitting the packet.<br><br>
|
785 |
*
|
786 |
* For a received packet:<br>
|
787 |
* The first byte will be XBEE_RX.<br>
|
788 |
* The second and third bytes will be the 16-bit
|
789 |
* address of the packet's sender.<br>
|
790 |
* The fourth byte is the signal strength.<br>
|
791 |
* The fifth byte is 1 if the packet were sent to
|
792 |
* a specific address, and 2 if it is a broadcast packet.<br><br>
|
793 |
*
|
794 |
* @param dest set to the packet data
|
795 |
* @return the length of the packet, or -1 if no packet
|
796 |
* is available
|
797 |
**/
|
798 |
int xbee_get_packet(unsigned char* dest) |
799 |
{ |
800 |
//start reading a packet with XBEE_FRAME_START
|
801 |
if (currentBufPos == 0) |
802 |
{ |
803 |
do
|
804 |
{ |
805 |
if (buffer_first == XBEE_BUFFER_SIZE)
|
806 |
buffer_first = 0;
|
807 |
// check if buffer is empty
|
808 |
if (buffer_first == buffer_last) {
|
809 |
return 0; |
810 |
} |
811 |
} while (arrival_buf[buffer_first++] != XBEE_FRAME_START);
|
812 |
|
813 |
if (buffer_first == XBEE_BUFFER_SIZE) {
|
814 |
buffer_first = 0;
|
815 |
} |
816 |
xbee_buf[0] = XBEE_FRAME_START;
|
817 |
currentBufPos++; |
818 |
} |
819 |
|
820 |
int len = -1; |
821 |
if (currentBufPos >= 3) { |
822 |
len = (int)xbee_buf[2] + ((int)xbee_buf[1] << 8); |
823 |
} |
824 |
|
825 |
while (len == -1 //packet length has not been read yet |
826 |
|| currentBufPos < len + 4)
|
827 |
{ |
828 |
if (currentBufPos == 3) |
829 |
{ |
830 |
len = (int)xbee_buf[2] + ((int)xbee_buf[1] << 8); |
831 |
if (len > 120) |
832 |
{ |
833 |
WL_DEBUG_PRINT("Packet too large. Probably error in XBee transmission.\n");
|
834 |
currentBufPos = 0;
|
835 |
return -1; |
836 |
} |
837 |
} |
838 |
|
839 |
// check if buffer is empty
|
840 |
if (buffer_first == buffer_last) {
|
841 |
return 0; |
842 |
} |
843 |
xbee_buf[currentBufPos++] = arrival_buf[buffer_first++]; |
844 |
if (buffer_first == XBEE_BUFFER_SIZE) {
|
845 |
buffer_first = 0;
|
846 |
} |
847 |
} |
848 |
|
849 |
currentBufPos = 0;
|
850 |
|
851 |
if (!xbee_verify_checksum(xbee_buf, len + 4)) |
852 |
{ |
853 |
WL_DEBUG_PRINT("XBee checksum failed.\r\n");
|
854 |
return -1; |
855 |
} |
856 |
|
857 |
//we will take care of the packet
|
858 |
if (xbee_handle_packet(xbee_buf + 3, len) != 0) { |
859 |
return 0; |
860 |
} |
861 |
|
862 |
if (dest == NULL) { |
863 |
return 0; |
864 |
} |
865 |
|
866 |
int i;
|
867 |
for (i = 3; i < len + 3; i++) { |
868 |
dest[i - 3] = xbee_buf[i];
|
869 |
} |
870 |
|
871 |
return len;
|
872 |
} |
873 |
|
874 |
/**
|
875 |
* Handles modem status packets.
|
876 |
*
|
877 |
* @param status the type of status packet received.
|
878 |
**/
|
879 |
void xbee_handle_status(char status) |
880 |
{ |
881 |
switch (status)
|
882 |
{ |
883 |
case 0: |
884 |
WL_DEBUG_PRINT("XBee hardware reset.\r\n");
|
885 |
break;
|
886 |
case 1: |
887 |
WL_DEBUG_PRINT("Watchdog timer reset.\r\n");
|
888 |
break;
|
889 |
case 2: |
890 |
WL_DEBUG_PRINT("Associated.\r\n");
|
891 |
break;
|
892 |
case 3: |
893 |
WL_DEBUG_PRINT("Disassociated.\r\n");
|
894 |
break;
|
895 |
case 4: |
896 |
WL_DEBUG_PRINT("Synchronization lost.\r\n");
|
897 |
break;
|
898 |
case 5: |
899 |
WL_DEBUG_PRINT("Coordinator realignment.\r\n");
|
900 |
break;
|
901 |
case 6: |
902 |
WL_DEBUG_PRINT("Coordinator started.\r\n");
|
903 |
break;
|
904 |
} |
905 |
} |
906 |
|
907 |
/**
|
908 |
* Handles AT command response packets.
|
909 |
* @param command the two character AT command, e.g. MY or ID
|
910 |
* @param result 0 for success, 1 for an error
|
911 |
* @param extra the hex value of the requested register
|
912 |
* @param extraLen the length in bytes of extra
|
913 |
**/
|
914 |
static void xbee_handle_at_command_response(char* command, char result, char* extra, int extraLen) |
915 |
{ |
916 |
if (result == 1) |
917 |
{ |
918 |
WL_DEBUG_PRINT("Error with AT");
|
919 |
WL_DEBUG_PRINT(command); |
920 |
WL_DEBUG_PRINT(" packet.\r\n");
|
921 |
} |
922 |
WL_DEBUG_PRINT("AT");
|
923 |
WL_DEBUG_PRINT(command); |
924 |
WL_DEBUG_PRINT(" command was successful.\r\n");
|
925 |
|
926 |
if (command[0] == 'I' && command[1] == 'D') |
927 |
{ |
928 |
xbee_panID = xbee_pending_panID; |
929 |
WL_DEBUG_PRINT("PAN ID set to ");
|
930 |
WL_DEBUG_PRINT_INT(xbee_panID); |
931 |
WL_DEBUG_PRINT(".\r\n");
|
932 |
return;
|
933 |
} |
934 |
|
935 |
if (command[0] == 'C' && command[1] == 'H') |
936 |
{ |
937 |
xbee_channel = xbee_pending_channel; |
938 |
WL_DEBUG_PRINT("Channel set to ");
|
939 |
WL_DEBUG_PRINT_INT(xbee_channel); |
940 |
WL_DEBUG_PRINT(".\r\n");
|
941 |
return;
|
942 |
} |
943 |
|
944 |
if (command[0] == 'M' && command[1] == 'Y' && extraLen != 0) |
945 |
{ |
946 |
// printf("reading xbee_address\n");
|
947 |
|
948 |
xbee_address = 0;
|
949 |
int i;
|
950 |
for (i = 0; i < extraLen; i++) { |
951 |
xbee_address = (xbee_address << 8) + extra[i];
|
952 |
} |
953 |
// printf("xbee address is: %d\n", xbee_address);
|
954 |
|
955 |
WL_DEBUG_PRINT("XBee address is ");
|
956 |
WL_DEBUG_PRINT_INT(xbee_address); |
957 |
WL_DEBUG_PRINT(".\r\n");
|
958 |
|
959 |
if (xbee_address == 0) |
960 |
{ |
961 |
printf("XBee 16-bit address must be set using ATMY.\r\n");
|
962 |
WL_DEBUG_PRINT("XBee 16-bit address must be set using ATMY.\r\n");
|
963 |
exit(0);
|
964 |
} |
965 |
} |
966 |
} |
967 |
|
968 |
/**
|
969 |
* Attempts to handle the packet if it is dealt with
|
970 |
* by the library.
|
971 |
* We will handle the following packet types:
|
972 |
* Modem Status
|
973 |
* AT Command Response
|
974 |
*
|
975 |
* @param packet the packet to handle
|
976 |
* @param len the length of the packet
|
977 |
*
|
978 |
* @return 1 if we have handled the packet, 0 otherwise
|
979 |
*/
|
980 |
static int xbee_handle_packet(char* packet, int len) |
981 |
{ |
982 |
//DEBUGGING PRINT
|
983 |
//printf("xbee_handle_packet: ");
|
984 |
//printHex(packet, len);
|
985 |
|
986 |
char command[3] = {1, 2, 3}; |
987 |
if (len <= 0) //this should not happend |
988 |
{ |
989 |
WL_DEBUG_PRINT("Non-positive packet length.\r\n");
|
990 |
return 0; |
991 |
} |
992 |
|
993 |
switch ((unsigned char)packet[0]) //packet type |
994 |
{ |
995 |
case XBEE_FRAME_STATUS:
|
996 |
xbee_handle_status(packet[1]);
|
997 |
return 1; |
998 |
case XBEE_FRAME_AT_COMMAND_RESPONSE:
|
999 |
printf("in XBEE_FRAME_AT_COMMAND_RESPONSE case\n");
|
1000 |
command[0] = packet[2]; |
1001 |
command[1] = packet[3]; |
1002 |
command[2] = 0; |
1003 |
xbee_handle_at_command_response(command, packet[4], packet + 5, len - 5); |
1004 |
return 1; |
1005 |
} |
1006 |
return 0; |
1007 |
} |
1008 |
|
1009 |
/**
|
1010 |
* Sets the personal area network id.
|
1011 |
*
|
1012 |
* @param id the new personal area network (PAN) id
|
1013 |
**/
|
1014 |
int xbee_set_pan_id(int id) |
1015 |
{ |
1016 |
char s[3]; |
1017 |
s[0] = (id >> 8) & 0xFF; |
1018 |
s[1] = id & 0xFF; |
1019 |
s[2] = 0; |
1020 |
xbee_pending_panID = id; |
1021 |
return xbee_send_modify_at_command("ID", s); |
1022 |
} |
1023 |
|
1024 |
/**
|
1025 |
* Get the PAN ID for the XBee.
|
1026 |
*
|
1027 |
* @return the personal area network id, or
|
1028 |
* XBEE_PAN_DEFAULT if it has not yet been set.
|
1029 |
**/
|
1030 |
//TODO: this function is so simple, it *may* be beneficial to inline this function. testing of if
|
1031 |
// it reduces code size or not should be done to be sure.
|
1032 |
unsigned int xbee_get_pan_id() |
1033 |
{ |
1034 |
return xbee_panID;
|
1035 |
} |
1036 |
|
1037 |
/**
|
1038 |
* Set the channel the XBee is using.
|
1039 |
*
|
1040 |
* @param channel the channel the XBee will not use,
|
1041 |
* between 0x0B and 0x1A
|
1042 |
*
|
1043 |
* @see xbee_get_channel
|
1044 |
**/
|
1045 |
int xbee_set_channel(int channel) |
1046 |
{ |
1047 |
if (channel < 0x0B || channel > 0x1A) |
1048 |
{ |
1049 |
WL_DEBUG_PRINT("Channel out of range.\r\n");
|
1050 |
return -1; |
1051 |
} |
1052 |
|
1053 |
char s[3]; |
1054 |
s[0] = channel & 0xFF; |
1055 |
s[1] = 0; |
1056 |
xbee_pending_channel = channel; |
1057 |
|
1058 |
return xbee_send_modify_at_command("CH", s); |
1059 |
} |
1060 |
|
1061 |
/**
|
1062 |
* Returns the channel which the XBee is currently using.
|
1063 |
*
|
1064 |
* @return the channel the XBee is using
|
1065 |
*
|
1066 |
* @see xbee_set_channel
|
1067 |
**/
|
1068 |
//TODO: this function is so simple, it *may* be beneficial to inline this function. testing of if
|
1069 |
// it reduces code size or not should be done to be sure.
|
1070 |
int xbee_get_channel(void) |
1071 |
{ |
1072 |
return xbee_channel;
|
1073 |
} |
1074 |
|
1075 |
/**
|
1076 |
* Get the 16-bit address of the XBee.
|
1077 |
* This is used to specify who to send messages to
|
1078 |
* and who messages are from.
|
1079 |
*
|
1080 |
* @return the 16-bit address of the XBee.
|
1081 |
**/
|
1082 |
//TODO: this function is so simple, it *may* be beneficial to inline this function. testing of if
|
1083 |
// it reduces code size or not should be done to be sure.
|
1084 |
unsigned int xbee_get_address() |
1085 |
{ |
1086 |
return xbee_address;
|
1087 |
} |
1088 |
|
1089 |
#ifndef ROBOT
|
1090 |
void xbee_set_com_port(char* port) |
1091 |
{ |
1092 |
xbee_com_port = port; |
1093 |
} |
1094 |
#endif
|