Revision 1494
wireless library branch
xbee.c | ||
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/** |
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* Copyright (c) 2007 Colony Project |
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* |
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* Permission is hereby granted, free of charge, to any person |
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* obtaining a copy of this software and associated documentation |
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* files (the "Software"), to deal in the Software without |
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* restriction, including without limitation the rights to use, |
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* copy, modify, merge, publish, distribute, sublicense, and/or sell |
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* copies of the Software, and to permit persons to whom the |
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* Software is furnished to do so, subject to the following |
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* conditions: |
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* |
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* The above copyright notice and this permission notice shall be |
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* included in all copies or substantial portions of the Software. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES |
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* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT |
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, |
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR |
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* OTHER DEALINGS IN THE SOFTWARE. |
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**/ |
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/** |
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* @file xbee.c |
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* @brief XBee Interface |
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* |
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* Implementation of low level communication with the XBee in API mode. |
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* |
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* @author Brian Coltin, Colony Project, CMU Robotics Club |
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**/ |
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#include "xbee.h" |
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#include "wl_defs.h" |
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#ifndef ROBOT |
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#include <fcntl.h> |
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#include <unistd.h> |
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#include <pthread.h> |
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#include <errno.h> |
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#include <termios.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#else |
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#include <serial.h> |
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#include <avr/interrupt.h> |
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#include <util/delay.h> |
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#endif |
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#include <string.h> |
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#define XBEE_FRAME_START 0x7E |
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#define XBEE_GET_PACKET_TIMEOUT 1000 |
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/*Frame Types*/ |
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#define XBEE_FRAME_STATUS 0x8A |
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#define XBEE_FRAME_AT_COMMAND 0x08 |
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#define XBEE_FRAME_AT_COMMAND_RESPONSE 0x88 |
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#define XBEE_FRAME_TX_REQUEST_64 0x00 |
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#define XBEE_FRAME_TX_REQUEST_16 0x01 |
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#define XBEE_FRAME_TX_STATUS XBEE_TX_STATUS |
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#define XBEE_FRAME_RX_64 0x80 |
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#define XBEE_FRAME_RX_16 XBEE_RX |
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/*Internal Function Prototypes*/ |
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/*I/O Functions*/ |
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static int xbee_send(char* buf, int size); |
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static int xbee_send_string(char* c); |
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#ifndef ROBOT |
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static int xbee_read(char* buf, int size); |
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#endif |
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/*Command Mode Functions |
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* Called during initialization. |
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*/ |
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static int xbee_enter_command_mode(void); |
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static int xbee_exit_command_mode(void); |
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static int xbee_enter_api_mode(void); |
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static int xbee_exit_api_mode(void); |
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static int xbee_wait_for_string(char* s, int len); |
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static int xbee_wait_for_ok(void); |
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/*API Mode Functions*/ |
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static int xbee_handle_packet(char* packet, int len); |
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static void xbee_handle_at_command_response(char* command, char result, char* extra, int extraLen); |
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static void xbee_handle_status(char status); |
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static int xbee_verify_checksum(char* packet, int len); |
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static char xbee_compute_checksum(char* packet, int len); |
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static int xbee_send_frame(char* buf, int len); |
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static int xbee_send_read_at_command(char* command); |
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static int xbee_send_modify_at_command(char* command, char* value); |
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/*Global Variables*/ |
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#ifndef ROBOT |
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static char* xbee_com_port = XBEE_PORT_DEFAULT; |
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static int xbee_stream; |
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static pthread_t* xbee_listen_thread; |
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#endif |
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// TODO: is this a good size? |
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#define XBEE_BUFFER_SIZE 128 |
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#define PACKET_BUFFER_SIZE 108 |
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// a buffer for data received from the XBee |
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char arrival_buf[XBEE_BUFFER_SIZE]; |
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// location of last unread byte in buffer |
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volatile int buffer_last = 0; |
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// first unread byte in buffer |
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volatile int buffer_first = 0; |
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//used to store packets as they are read |
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static char xbee_buf[PACKET_BUFFER_SIZE]; |
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static int currentBufPos = 0; |
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//XBee status |
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static unsigned int xbee_panID = XBEE_PAN_DEFAULT; |
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static unsigned int xbee_pending_panID = XBEE_PAN_DEFAULT; |
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static int xbee_channel = XBEE_CHANNEL_DEFAULT; |
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static int xbee_pending_channel = XBEE_CHANNEL_DEFAULT; |
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static volatile unsigned int xbee_address = 0; |
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/*Function Implementations*/ |
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#ifdef ROBOT |
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/** |
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* Interrupt for the robot. Adds bytes received from the xbee |
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* to the buffer. |
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**/ |
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#ifndef FIREFLY |
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ISR(USART1_RX_vect) |
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{ |
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char c = UDR1; |
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arrival_buf[buffer_last] = c; |
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int t = buffer_last + 1; |
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if (t == XBEE_BUFFER_SIZE) |
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t = 0; |
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if (t == buffer_first) |
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{ |
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WL_DEBUG_PRINT("\nOut of space in buffer.\n"); |
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} |
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buffer_last = t; |
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} |
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#else |
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SIGNAL(SIG_USART0_RECV) |
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{ |
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char c = UDR0; |
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arrival_buf[buffer_last] = c; |
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int t = buffer_last + 1; |
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if (t == XBEE_BUFFER_SIZE) |
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t = 0; |
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if (t == buffer_first) |
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{ |
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WL_DEBUG_PRINT("Out of space in buffer.\n"); |
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} |
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buffer_last = t; |
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} |
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#endif |
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#else |
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// Computer code |
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/** |
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* Thread that listens to the xbee. |
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**/ |
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static void* listen_to_xbee(void* x) |
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{ |
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char c; |
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while (1) |
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{ |
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if (xbee_read(&c, 1) != 0) { |
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WL_DEBUG_PRINT("xbee_read failed.\n"); |
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return NULL; |
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} |
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arrival_buf[buffer_last] = c; |
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int t = buffer_last + 1; |
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if (t == XBEE_BUFFER_SIZE) |
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t = 0; |
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if (t == buffer_first) |
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{ |
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WL_DEBUG_PRINT("Out of space in buffer.\n"); |
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} |
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buffer_last = t; |
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usleep(1000); |
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} |
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return NULL; |
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} |
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#endif |
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/** |
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* Initializes the XBee library so that other functions may be used. |
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**/ |
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int xbee_lib_init() |
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{ |
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WL_DEBUG_PRINT("in xbee_init\n"); |
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#ifdef ROBOT |
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// enable basic xbee serial communications |
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xbee_init(); |
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// enable the receiving interrupt for USART1 |
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#ifdef FIREFLY |
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UCSR0B |= _BV(RXCIE) | _BV(RXEN); |
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#else |
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#ifdef BAYBOARD |
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UCSR1B |= _BV(RXCIE1); |
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#else |
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// dragonfly register |
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UCSR1B |= _BV(RXCIE); |
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#endif |
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#endif |
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sei(); |
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#else |
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// this is computer only code |
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xbee_stream = open(xbee_com_port, O_RDWR); |
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if (xbee_stream == -1/* || lockf(xbee_stream, F_TEST, 0) != 0*/) |
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{ |
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WL_DEBUG_PRINT("Failed to open connection to XBee on port "); |
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WL_DEBUG_PRINT_INT(xbee_com_port); |
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WL_DEBUG_PRINT(".\n"); |
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return -1; |
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} else { |
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WL_DEBUG_PRINT("Successfully opened connection to XBee on port "); |
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WL_DEBUG_PRINT_INT(xbee_com_port); |
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WL_DEBUG_PRINT(".\n"); |
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} |
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// set baud rate, etc. correctly |
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struct termios options; |
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tcgetattr(xbee_stream, &options); |
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cfsetispeed(&options, B9600); |
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cfsetospeed(&options, B9600); |
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options.c_iflag &= ~ICRNL; |
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options.c_oflag &= ~OCRNL; |
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options.c_cflag |= (CLOCAL | CREAD); |
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options.c_cflag &= ~PARENB; |
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options.c_cflag &= ~CSTOPB; |
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options.c_cflag &= ~CSIZE; |
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options.c_cflag |= CS8; |
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options.c_lflag &= ~ICANON; |
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options.c_cc[VMIN] = 1; |
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options.c_cc[VTIME] = 50; |
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if (tcsetattr(xbee_stream, TCSANOW, &options)) |
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{ |
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WL_DEBUG_PRINT("Error setting attributes.\n"); |
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return -1; |
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} |
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xbee_listen_thread = (pthread_t*)malloc(sizeof(pthread_t)); |
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if (xbee_listen_thread == NULL) |
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{ |
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WL_DEBUG_PRINT("Malloc failed.\n"); |
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return -1; |
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} |
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int ret = pthread_create(xbee_listen_thread, NULL, listen_to_xbee, NULL); |
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if (ret) |
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{ |
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WL_DEBUG_PRINT("Failed to create listener thread.\n"); |
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return -1; |
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} |
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#endif |
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WL_DEBUG_PRINT("Entering command mode.\n"); |
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if (xbee_enter_command_mode() != 0) { |
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return -1; |
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} |
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WL_DEBUG_PRINT("Entered command mode.\n"); |
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if (xbee_enter_api_mode() != 0) { |
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return -1; |
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} |
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WL_DEBUG_PRINT("Entered api mode.\n"); |
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if (xbee_exit_command_mode() != 0) { |
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return -1; |
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} |
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WL_DEBUG_PRINT("Left command mode.\n"); |
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if (xbee_send_read_at_command("MY")) { |
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return -1; |
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} |
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WL_DEBUG_PRINT("Getting ATMY address.\n"); |
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#ifndef ROBOT |
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int i; |
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for (i = 0; xbee_address == 0 && i < XBEE_GET_PACKET_TIMEOUT; i++) { |
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ret = xbee_get_packet(NULL); |
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usleep(1000); |
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/* if (ret == -1) { */ |
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/* WL_DEBUG_PRINT("xbee_get_packet(NULL) failed.\n"); */ |
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/* return -1; */ |
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/* } */ |
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} |
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#else |
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//wait to return until the address is set |
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//TODO: this shouldn't wait indefinitely. There should be some sort of reasonable timeout |
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// so if the address is never set right, an error can be returned instead of having the |
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// robot hang forever |
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while (xbee_address == 0) { |
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xbee_get_packet(NULL); |
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} |
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#endif |
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WL_DEBUG_PRINT("Got ATMY address.\n"); |
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#ifndef ROBOT |
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if (i == XBEE_GET_PACKET_TIMEOUT) { // We timed-out. |
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WL_DEBUG_PRINT("xbee_get_packet timed out.\n"); |
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return -1; |
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} else { |
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return 0; |
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} |
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#else |
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return 0; |
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#endif |
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} |
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/** |
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* Call when finished using the XBee library. This releases |
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* all sued resources. |
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**/ |
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void xbee_terminate() |
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{ |
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#ifndef ROBOT |
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pthread_cancel(*xbee_listen_thread); |
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pthread_join(*xbee_listen_thread, NULL); |
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free(xbee_listen_thread); |
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lockf(xbee_stream, F_ULOCK, 0); |
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close(xbee_stream); |
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#else |
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xbee_exit_api_mode(); |
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#endif |
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} |
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/** |
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* Send a buffer buf of size bytes to the XBee. |
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* |
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* @param buf the buffer of data to send |
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* @param size the number of bytes to send |
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**/ |
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static int xbee_send(char* buf, int size) |
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{ |
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#ifdef ROBOT |
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int i; |
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for (i = 0; i < size; i++) { |
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xbee_putc(buf[i]); |
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} |
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return 0; |
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#else |
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int ret = write(xbee_stream, buf, size); |
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//success |
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if (ret == size) |
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return 0; |
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if (ret == -1) |
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{ |
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//interrupted by system signal, probably timer interrupt. |
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//just try again |
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if (errno == 4) |
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{ |
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return xbee_send(buf, size); |
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} |
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WL_DEBUG_PRINT("Failed to write to xbee\r\n"); |
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return -1; |
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} |
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//write was interrupted after writing ret bytes |
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return xbee_send(buf + ret, size - ret); |
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#endif |
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} |
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/** |
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* Sends a string to the XBee. |
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* |
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* @param c the string to send to the XBEE |
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**/ |
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static int xbee_send_string(char* c) |
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{ |
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return xbee_send(c, strlen(c)); |
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} |
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#ifndef ROBOT |
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static int xbee_read(char* buf, int size) |
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{ |
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if (read(xbee_stream, buf, size) == -1) { |
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WL_DEBUG_PRINT("Failed to read from xbee.\r\n"); |
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return -1; |
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} |
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return 0; |
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} |
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#endif |
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/** |
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* Enter into command mode. |
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**/ |
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static int xbee_enter_command_mode() |
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{ |
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if (xbee_send_string("+++") != 0) { |
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return -1; |
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} |
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if (xbee_wait_for_ok() != 0) { |
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return -1; |
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} |
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return 0; |
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} |
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/** |
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* Exit from command mode. |
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**/ |
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static int xbee_exit_command_mode() |
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{ |
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if (xbee_send_string("ATCN\r") != 0) { |
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return -1; |
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} |
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xbee_wait_for_ok(); |
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return 0; |
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} |
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/** |
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* Enter API mode. |
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**/ |
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static int xbee_enter_api_mode() |
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{ |
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if (xbee_send_string("ATAP 1\r") != 0) { |
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return -1; |
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} |
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xbee_wait_for_ok(); |
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return 0; |
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} |
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/** |
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* Exit API mode. |
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**/ |
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static int xbee_exit_api_mode() |
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{ |
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if (xbee_send_modify_at_command("AP","0") != 0) { |
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return -1; |
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} |
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return 0; |
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} |
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475 |
|
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/** |
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* Wait until the string "OK\r" is received from the XBee. |
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**/ |
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static int xbee_wait_for_ok() |
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{ |
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return xbee_wait_for_string("OK\r", 3); |
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} |
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483 |
|
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/** |
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* Delay until the specified string is received from |
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* the XBee. Discards all other XBee data. |
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* |
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* @param s the string to receive |
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* @param len the length of the string |
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**/ |
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491 |
static int xbee_wait_for_string(char* s, int len) |
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492 |
{ |
|
493 |
char* curr = s; |
|
494 |
while (curr - s < len) { |
|
495 |
// check if buffer is empty |
|
496 |
if (buffer_last != buffer_first) { |
|
497 |
char c = arrival_buf[buffer_first++]; |
|
498 |
if (buffer_first == XBEE_BUFFER_SIZE) { |
|
499 |
buffer_first = 0; |
|
500 |
} |
|
501 |
|
|
502 |
if (c == *curr) { |
|
503 |
curr++; |
|
504 |
} else { |
|
505 |
#ifndef ROBOT |
|
506 |
//return -1; // Computer is less forgiving. |
|
507 |
curr = s; |
|
508 |
#else |
|
509 |
curr = s; |
|
510 |
#endif |
|
511 |
} |
|
512 |
} // else buffer is empty. |
|
513 |
|
|
514 |
#ifndef ROBOT |
|
515 |
usleep(100); |
|
516 |
#endif |
|
517 |
} |
|
518 |
|
|
519 |
return 0; |
|
520 |
} |
|
521 |
|
|
522 |
/** |
|
523 |
* Verifies that the packets checksum is correct. |
|
524 |
* (If the checksum is correct, the sum of the bytes |
|
525 |
* is 0xFF.) |
|
526 |
* |
|
527 |
* @param packet the packet received. This includes the first |
|
528 |
* three bytes, which are header information from the XBee. |
|
529 |
* |
|
530 |
* @param len The length of the packet received from the XBee |
|
531 |
* |
|
532 |
* @return 0 if the checksum is incorrect, nonzero |
|
533 |
* otherwise |
|
534 |
**/ |
|
535 |
int xbee_verify_checksum(char* packet, int len) |
|
536 |
{ |
|
537 |
unsigned char sum = 0; |
|
538 |
int i; |
|
539 |
for (i = 3; i < len; i++) |
|
540 |
sum += (unsigned char)packet[i]; |
|
541 |
return sum == 0xFF; |
|
542 |
} |
|
543 |
|
|
544 |
/** |
|
545 |
* Returns the checksum of the given packet. |
|
546 |
* |
|
547 |
* @param buf the data for the packet to send |
|
548 |
* @param len the length of the packet in bytes |
|
549 |
* |
|
550 |
* @return the checksum of the packet, which will |
|
551 |
* become the last byte sent in the packet |
|
552 |
**/ |
|
553 |
char xbee_compute_checksum(char* buf, int len) |
|
554 |
{ |
|
555 |
int i; |
|
556 |
unsigned char sum = 0; |
|
557 |
for (i = 0; i < len; i++) |
|
558 |
sum += (unsigned char)buf[i]; |
|
559 |
return 0xFF - sum; |
|
560 |
} |
|
561 |
|
|
562 |
/** |
|
563 |
* Adds header information and checksum to the given |
|
564 |
* packet and sends it. Header information includes |
|
565 |
* XBEE_FRAME_START and the packet length, as two bytes. |
|
566 |
* |
|
567 |
* @param buf the packet data |
|
568 |
* @param len the size in bytes of the packet data |
|
569 |
* |
|
570 |
**/ |
|
571 |
static int xbee_send_frame(char* buf, int len) |
|
572 |
{ |
|
573 |
char prefix[3]; |
|
574 |
prefix[0] = XBEE_FRAME_START; |
|
575 |
prefix[1] = (len & 0xFF00) >> 8; |
|
576 |
prefix[2] = len & 0xFF; |
|
577 |
char checksum = xbee_compute_checksum(buf, len); |
|
578 |
|
|
579 |
if (xbee_send(prefix, 3) != 0) { |
|
580 |
return -1; |
|
581 |
} |
|
582 |
|
|
583 |
if (xbee_send(buf, len) != 0) { |
|
584 |
return -1; |
|
585 |
} |
|
586 |
|
|
587 |
if (xbee_send(&checksum, 1) != 0) { |
|
588 |
return -1; |
|
589 |
} |
|
590 |
|
|
591 |
return 0; |
|
592 |
} |
|
593 |
|
|
594 |
/** |
|
595 |
* Resets the XBee Modem (including baud rate when on robot) |
|
596 |
* |
|
597 |
* Used for launching bootloader |
|
598 |
**/ |
|
599 |
int xbee_reset(void) |
|
600 |
{ |
|
601 |
#ifdef ROBOT |
|
602 |
xbee_send_modify_at_command("BD", "3"); |
|
603 |
#endif |
|
604 |
xbee_send_read_at_command("FR"); |
|
605 |
// delay 150 ms to wait for reset |
|
606 |
#ifndef ROBOT |
|
607 |
usleep(150000); |
|
608 |
#else |
|
609 |
_delay_ms(150); |
|
610 |
#endif |
|
611 |
|
|
612 |
return 0; |
|
613 |
} |
|
614 |
|
|
615 |
/** |
|
616 |
* Sends an AT command to read a parameter. |
|
617 |
* |
|
618 |
* @param command the AT command to send. For exmaple, |
|
619 |
* use ID to read the PAN ID and MY to return the XBee ID. |
|
620 |
* See the XBee reference guide for a complete listing. |
|
621 |
**/ |
|
622 |
static int xbee_send_read_at_command(char* command) |
|
623 |
{ |
|
624 |
return xbee_send_modify_at_command(command, NULL); |
|
625 |
} |
|
626 |
|
|
627 |
/** |
|
628 |
* Sends the given AT command. |
|
629 |
* |
|
630 |
* @param command the AT command to send (e.g., MY, ID) |
|
631 |
* @param value the value to pass as a parameter |
|
632 |
* (or NULL if there is no parameter) |
|
633 |
**/ |
|
634 |
static int xbee_send_modify_at_command(char* command, char* value) |
|
635 |
{ |
|
636 |
char buf[16]; |
|
637 |
int i; |
|
638 |
|
|
639 |
buf[0] = XBEE_FRAME_AT_COMMAND; |
|
640 |
buf[1] = 1; |
|
641 |
buf[2] = command[0]; |
|
642 |
buf[3] = command[1]; |
|
643 |
int valueLen = 0; |
|
644 |
if (value != NULL) |
|
645 |
{ |
|
646 |
valueLen = strlen(value); |
|
647 |
if (valueLen > 8) |
|
648 |
{ |
|
649 |
WL_DEBUG_PRINT("AT Command too large.\r\n"); |
|
650 |
return -1; |
|
651 |
} |
|
652 |
|
|
653 |
for (i = 0; i < valueLen; i++) { |
|
654 |
buf[4 + i] = value[i]; |
|
655 |
} |
|
656 |
} |
|
657 |
|
|
658 |
return xbee_send_frame(buf, 4 + valueLen); |
|
659 |
} |
|
660 |
|
|
661 |
/** |
|
662 |
* Send the specified packet. |
|
663 |
* |
|
664 |
* @param packet the packet data to send |
|
665 |
* @param len the number of bytes in the packet |
|
666 |
* |
|
667 |
* @param dest the ID of the XBee to send the packet to, |
|
668 |
* or XBEE_BROADCAST to send the message to all robots |
|
669 |
* in the PAN. |
|
670 |
* |
|
671 |
* @param options a combination of the flags |
|
672 |
* XBEE_OPTIONS_NONE, XBEE_OPTIONS_DISABLE_RESPONSE and |
|
673 |
* XBEE_OPTIONS_BROADCAST_ALL_PANS |
|
674 |
* |
|
675 |
* @param frame the frame number to associate this packet |
|
676 |
* with. This will be used to identify the response when |
|
677 |
* the XBee alerts us as to whether or not our message |
|
678 |
* was received. |
|
679 |
**/ |
|
680 |
int xbee_send_packet(char* packet, int len, int dest, char options, char frame) |
|
681 |
{ |
|
682 |
char buf[5]; |
|
683 |
char prefix[3]; |
|
684 |
int i; |
|
685 |
unsigned char checksum = 0; |
|
686 |
|
|
687 |
if (len > 100) |
|
688 |
{ |
|
689 |
WL_DEBUG_PRINT("Packet is too large.\r\n"); |
|
690 |
return -1; |
|
691 |
} |
|
692 |
|
|
693 |
//data for sending request |
|
694 |
buf[0] = XBEE_FRAME_TX_REQUEST_16; |
|
695 |
buf[1] = frame; |
|
696 |
buf[2] = (dest >> 8) & 0xFF; |
|
697 |
buf[3] = dest & 0xFF; |
|
698 |
buf[4] = options; |
|
699 |
|
|
700 |
//packet prefix, do this here so we don't need an extra buffer |
|
701 |
prefix[0] = XBEE_FRAME_START; |
|
702 |
prefix[1] = ((5 + len) & 0xFF00) >> 8; |
|
703 |
prefix[2] = (5 + len) & 0xFF; |
|
704 |
|
|
705 |
for (i = 0; i < 5; i++) |
|
706 |
checksum += (unsigned char)buf[i]; |
|
707 |
for (i = 0; i < len; i++) |
|
708 |
checksum += (unsigned char)packet[i]; |
|
709 |
checksum = 0xFF - checksum; |
|
710 |
|
|
711 |
if (xbee_send(prefix, 3) != 0) { |
|
712 |
return -1; |
|
713 |
} |
|
714 |
|
|
715 |
if (xbee_send(buf, 5) != 0) { |
|
716 |
return -1; |
|
717 |
} |
|
718 |
|
|
719 |
if (xbee_send(packet, len) != 0) { |
|
720 |
return -1; |
|
721 |
} |
|
722 |
|
|
723 |
if (xbee_send((char*)&checksum, 1) != 0) { |
|
724 |
return -1; |
|
725 |
} |
|
726 |
|
|
727 |
return 0; |
|
728 |
} |
|
729 |
|
|
730 |
/** |
|
731 |
* Reads a packet received from the XBee. This function |
|
732 |
* is non-blocking. The resulting packet is stored in dest. |
|
733 |
* Only returns transmission response packets and |
|
734 |
* received packets. The returned packet does not include |
|
735 |
* header information or the checksum. This method also |
|
736 |
* handles special packets dealt with by the XBee library, |
|
737 |
* and so should be called frequently while the XBee is in |
|
738 |
* use.<br><br> |
|
739 |
* |
|
740 |
* The first byte of the packet will be either |
|
741 |
* XBEE_TX_STATUS or XBEE_RX to indicated |
|
742 |
* a response to a sent message or a received message, |
|
743 |
* respectively.<br><br> |
|
744 |
* |
|
745 |
* For a status response packet:<br> |
|
746 |
* The first byte will be XBEE_TX_STATUS.<br> |
|
747 |
* The second byte will be the frame number.<br> |
|
748 |
* The third byte will be the result. 0 indicates success, |
|
749 |
* and nonzero indicates that an error ocurred in |
|
750 |
* transmitting the packet.<br><br> |
|
751 |
* |
|
752 |
* For a received packet:<br> |
|
753 |
* The first byte will be XBEE_RX.<br> |
|
754 |
* The second and third bytes will be the 16-bit |
|
755 |
* address of the packet's sender.<br> |
|
756 |
* The fourth byte is the signal strength.<br> |
|
757 |
* The fifth byte is 1 if the packet were sent to |
|
758 |
* a specific address, and 2 if it is a broadcast packet.<br><br> |
|
759 |
* |
|
760 |
* @param dest set to the packet data |
|
761 |
* @return the length of the packet, or -1 if no packet |
|
762 |
* is available |
|
763 |
**/ |
|
764 |
int xbee_get_packet(unsigned char* dest) |
|
765 |
{ |
|
766 |
int ret; |
|
767 |
//start reading a packet with XBEE_FRAME_START |
|
768 |
if (currentBufPos == 0) |
|
769 |
{ |
|
770 |
do |
|
771 |
{ |
|
772 |
if (buffer_first == XBEE_BUFFER_SIZE) |
|
773 |
buffer_first = 0; |
|
774 |
// check if buffer is empty |
|
775 |
if (buffer_first == buffer_last) { |
|
776 |
return -1; |
|
777 |
} |
|
778 |
} while (arrival_buf[buffer_first++] != XBEE_FRAME_START); |
|
779 |
|
|
780 |
if (buffer_first == XBEE_BUFFER_SIZE) { |
|
781 |
buffer_first = 0; |
|
782 |
} |
|
783 |
xbee_buf[0] = XBEE_FRAME_START; |
|
784 |
currentBufPos++; |
|
785 |
} |
|
786 |
|
|
787 |
int len = -1; |
|
788 |
if (currentBufPos >= 3) { |
|
789 |
len = (int)xbee_buf[2] + ((int)xbee_buf[1] << 8); |
|
790 |
} |
|
791 |
|
|
792 |
while (len == -1 //packet length has not been read yet |
|
793 |
|| currentBufPos < len + 4) |
|
794 |
{ |
|
795 |
if (currentBufPos == 3) |
|
796 |
{ |
|
797 |
len = (int)xbee_buf[2] + ((int)xbee_buf[1] << 8); |
|
798 |
if (len > 120) |
|
799 |
{ |
|
800 |
WL_DEBUG_PRINT("Packet too large. Probably error in XBee transmission.\n"); |
|
801 |
currentBufPos = 0; |
|
802 |
return -1; |
|
803 |
} |
|
804 |
} |
|
805 |
|
|
806 |
// check if buffer is empty |
|
807 |
if (buffer_first == buffer_last) { |
|
808 |
return -1; |
|
809 |
} |
|
810 |
xbee_buf[currentBufPos++] = arrival_buf[buffer_first++]; |
|
811 |
if (buffer_first == XBEE_BUFFER_SIZE) { |
|
812 |
buffer_first = 0; |
|
813 |
} |
|
814 |
} |
|
815 |
|
|
816 |
currentBufPos = 0; |
|
817 |
|
|
818 |
if (!xbee_verify_checksum(xbee_buf, len + 4)) |
|
819 |
{ |
|
820 |
WL_DEBUG_PRINT("XBee checksum failed.\r\n"); |
|
821 |
return -1; |
|
822 |
} |
|
823 |
|
|
824 |
//we will take care of the packet |
|
825 |
|
|
826 |
ret = xbee_handle_packet(xbee_buf+3, len); |
|
827 |
if (ret == 1) { |
|
828 |
return 3; |
|
829 |
} |
|
830 |
|
|
831 |
if (dest == NULL) { |
|
832 |
return -1; |
|
833 |
} |
|
834 |
|
|
835 |
int i; |
|
836 |
for (i = 3; i < len + 3; i++) { |
|
837 |
dest[i - 3] = xbee_buf[i]; |
|
838 |
} |
|
839 |
return len; |
|
840 |
} |
|
841 |
|
|
842 |
/** |
|
843 |
* Handles modem status packets. |
|
844 |
* |
|
845 |
* @param status the type of status packet received. |
|
846 |
**/ |
|
847 |
void xbee_handle_status(char status) |
|
848 |
{ |
|
849 |
switch (status) |
|
850 |
{ |
|
851 |
case 0: |
|
852 |
WL_DEBUG_PRINT("XBee hardware reset.\r\n"); |
|
853 |
break; |
|
854 |
case 1: |
|
855 |
WL_DEBUG_PRINT("Watchdog timer reset.\r\n"); |
|
856 |
break; |
|
857 |
case 2: |
|
858 |
WL_DEBUG_PRINT("Associated.\r\n"); |
|
859 |
break; |
|
860 |
case 3: |
|
861 |
WL_DEBUG_PRINT("Disassociated.\r\n"); |
|
862 |
break; |
|
863 |
case 4: |
|
864 |
WL_DEBUG_PRINT("Synchronization lost.\r\n"); |
|
865 |
break; |
|
866 |
case 5: |
|
867 |
WL_DEBUG_PRINT("Coordinator realignment.\r\n"); |
|
868 |
break; |
|
869 |
case 6: |
|
870 |
WL_DEBUG_PRINT("Coordinator started.\r\n"); |
|
871 |
break; |
|
872 |
} |
|
873 |
} |
|
874 |
|
|
875 |
/** |
|
876 |
* Handles AT command response packets. |
|
877 |
* @param command the two character AT command, e.g. MY or ID |
|
878 |
* @param result 0 for success, 1 for an error |
|
879 |
* @param extra the hex value of the requested register |
|
880 |
* @param extraLen the length in bytes of extra |
|
881 |
**/ |
|
882 |
static void xbee_handle_at_command_response(char* command, char result, char* extra, int extraLen) |
|
883 |
{ |
|
884 |
if (result == 1) |
|
885 |
{ |
|
886 |
WL_DEBUG_PRINT("Error with AT"); |
|
887 |
WL_DEBUG_PRINT(command); |
|
888 |
WL_DEBUG_PRINT(" packet.\r\n"); |
|
889 |
} |
|
890 |
WL_DEBUG_PRINT("AT"); |
|
891 |
WL_DEBUG_PRINT(command); |
|
892 |
WL_DEBUG_PRINT(" command was successful.\r\n"); |
|
893 |
|
|
894 |
if (command[0] == 'I' && command[1] == 'D') |
|
895 |
{ |
|
896 |
xbee_panID = xbee_pending_panID; |
|
897 |
WL_DEBUG_PRINT("PAN ID set to "); |
|
898 |
WL_DEBUG_PRINT_INT(xbee_panID); |
|
899 |
WL_DEBUG_PRINT(".\r\n"); |
|
900 |
return; |
|
901 |
} |
|
902 |
|
|
903 |
if (command[0] == 'C' && command[1] == 'H') |
|
904 |
{ |
|
905 |
xbee_channel = xbee_pending_channel; |
|
906 |
WL_DEBUG_PRINT("Channel set to "); |
|
907 |
WL_DEBUG_PRINT_INT(xbee_channel); |
|
908 |
WL_DEBUG_PRINT(".\r\n"); |
|
909 |
return; |
|
910 |
} |
|
911 |
|
|
912 |
if (command[0] == 'M' && command[1] == 'Y' && extraLen != 0) |
|
913 |
{ |
|
914 |
xbee_address = 0; |
|
915 |
int i; |
|
916 |
for (i = 0; i < extraLen; i++) { |
|
917 |
xbee_address = (xbee_address << 8) + extra[i]; |
|
918 |
} |
|
919 |
|
|
920 |
WL_DEBUG_PRINT("XBee address is "); |
|
921 |
WL_DEBUG_PRINT_INT(xbee_address); |
|
922 |
WL_DEBUG_PRINT(".\r\n"); |
|
923 |
|
|
924 |
if (xbee_address == 0) |
|
925 |
{ |
|
926 |
WL_DEBUG_PRINT("XBee 16-bit address must be set using ATMY.\r\n"); |
|
927 |
#ifndef ROBOT |
|
928 |
exit(0); |
|
929 |
#endif |
|
930 |
} |
|
931 |
} |
|
932 |
} |
|
933 |
|
|
934 |
/** |
|
935 |
* Attempts to handle the packet if it is dealt with |
|
936 |
* by the library. |
|
937 |
* We will handle the following packet types: |
|
938 |
* Modem Status |
|
939 |
* AT Command Response |
|
940 |
* |
|
941 |
* @param packet the packet to handle |
|
942 |
* @param len the length of the packet |
|
943 |
* |
|
944 |
* @return 1 if we have handled the packet, 0 otherwise |
|
945 |
*/ |
|
946 |
static int xbee_handle_packet(char* packet, int len) |
|
947 |
{ |
|
948 |
|
|
949 |
char command[3] = {1, 2, 3}; |
|
950 |
if (len <= 0) //this should not happend |
|
951 |
{ |
|
952 |
WL_DEBUG_PRINT("Non-positive packet length.\r\n"); |
|
953 |
return 0; |
|
954 |
} |
|
955 |
|
|
956 |
switch ((unsigned char)packet[0]) //packet type |
|
957 |
{ |
|
958 |
case XBEE_FRAME_STATUS: |
|
959 |
xbee_handle_status(packet[1]); |
|
960 |
return 1; |
|
961 |
case XBEE_FRAME_AT_COMMAND_RESPONSE: |
|
962 |
command[0] = packet[2]; |
|
963 |
command[1] = packet[3]; |
|
964 |
command[2] = 0; |
|
965 |
xbee_handle_at_command_response(command, packet[4], packet + 5, len - 5); |
|
966 |
return 1; |
|
967 |
} |
|
968 |
return 0; |
|
969 |
} |
|
970 |
|
|
971 |
/** |
|
972 |
* Sets the personal area network id. |
|
973 |
* |
|
974 |
* @param id the new personal area network (PAN) id |
|
975 |
**/ |
|
976 |
int xbee_set_pan_id(int id) |
|
977 |
{ |
|
978 |
char s[3]; |
|
979 |
s[0] = (id >> 8) & 0xFF; |
|
980 |
s[1] = id & 0xFF; |
|
981 |
s[2] = 0; |
|
982 |
xbee_pending_panID = id; |
|
983 |
return xbee_send_modify_at_command("ID", s); |
|
984 |
} |
|
985 |
|
|
986 |
/** |
|
987 |
* Get the PAN ID for the XBee. |
|
988 |
* |
|
989 |
* @return the personal area network id, or |
|
990 |
* XBEE_PAN_DEFAULT if it has not yet been set. |
|
991 |
**/ |
|
992 |
unsigned int xbee_get_pan_id() |
|
993 |
{ |
|
994 |
return xbee_panID; |
|
995 |
} |
|
996 |
|
|
997 |
/** |
|
998 |
* Set the channel the XBee is using. |
|
999 |
* |
|
1000 |
* @param channel the channel the XBee will not use, |
|
1001 |
* between 0x0B and 0x1A |
|
1002 |
* |
|
1003 |
* @see xbee_get_channel |
|
1004 |
**/ |
|
1005 |
int xbee_set_channel(int channel) |
|
1006 |
{ |
|
1007 |
if (channel < 0x0B || channel > 0x1A) |
|
1008 |
{ |
|
1009 |
WL_DEBUG_PRINT("Channel out of range.\r\n"); |
|
1010 |
return -1; |
|
1011 |
} |
|
1012 |
|
|
1013 |
char s[3]; |
|
1014 |
s[0] = channel & 0xFF; |
|
1015 |
s[1] = 0; |
|
1016 |
xbee_pending_channel = channel; |
|
1017 |
|
|
1018 |
return xbee_send_modify_at_command("CH", s); |
|
1019 |
} |
|
1020 |
|
|
1021 |
/** |
|
1022 |
* Returns the channel which the XBee is currently using. |
|
1023 |
* |
|
1024 |
* @return the channel the XBee is using |
|
1025 |
* |
|
1026 |
* @see xbee_set_channel |
|
1027 |
**/ |
|
1028 |
int xbee_get_channel(void) |
|
1029 |
{ |
|
1030 |
return xbee_channel; |
|
1031 |
} |
|
1032 |
|
|
1033 |
/** |
|
1034 |
* Get the 16-bit address of the XBee. |
|
1035 |
* This is used to specify who to send messages to |
|
1036 |
* and who messages are from. |
|
1037 |
* |
|
1038 |
* @return the 16-bit address of the XBee. |
|
1039 |
**/ |
|
1040 |
unsigned int xbee_get_address() |
|
1041 |
{ |
|
1042 |
return xbee_address; |
|
1043 |
} |
|
1044 |
|
|
1045 |
#ifndef ROBOT |
|
1046 |
void xbee_set_com_port(char* port) |
|
1047 |
{ |
|
1048 |
xbee_com_port = port; |
|
1049 |
} |
|
1050 |
#endif |
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