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/**
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* Copyright (c) 2009 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 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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#include <time.h> |
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// TODO: separate robot and computer code into two xbee.c files
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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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#else
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#include <serial.h> // TODO: integrate serial xbee functions into this file |
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#include <avr/interrupt.h> |
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#endif
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// TODO: do we really need stdio and stdlib in the robot code?
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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/*Internal Function Prototypes*/
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// TODO: convert all int references to int16_t syntax (see stdint.h)
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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 int 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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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: clarify buffers, what they're used for, etc
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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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/**@addtogroup xbee
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* @{ **/
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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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if (xbee_init() != 0) { |
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usb_puts("xbee_init error");
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return -1; |
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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 the receiving interrupt
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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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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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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.\r\n");
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if (xbee_enter_command_mode() != 0) { |
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usb_puts("error entering command mode\r\n");
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return -1; |
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} |
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WL_DEBUG_PRINT("Entered command mode.\r\n");
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// reset baud rate
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WL_DEBUG_PRINT("Resetting Baud to ");
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WL_DEBUG_PRINT(XBEE_BAUD_STR); |
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WL_DEBUG_PRINT("\r\n");
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// set baud on xbee
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//#if (XBEE_BAUD == 250000)
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#if (XBEE_BAUD == 115200) |
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xbee_send_string("ATBD7\r\n");
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#elif (XBEE_BAUD == 57600) |
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xbee_send_string("ATBD6\r\n");
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#elif (XBEE_BAUD == 38400) |
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xbee_send_string("ATBD5\r\n");
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#elif (XBEE_BAUD == 19200) |
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xbee_send_string("ATBD4\r\n");
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#elif (XBEE_BAUD == 9600) |
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// already at this baud rate
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//xbee_send_string("ATBD3\r\n");
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#else
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WL_DEBUG_PRINT("undefined baud rate\r\n");
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#endif
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// exit command mode
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xbee_wait_for_ok(); |
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WL_DEBUG_PRINT("got ok from baud reset\r\n");
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xbee_send_string("ATCN\r\n");
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xbee_wait_for_ok(); |
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WL_DEBUG_PRINT("got ok from exiting command mode\r\n");
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// set UART baud
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#if (XBEE_BAUD == 250000) |
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UBRR1H = 0x00;
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UBRR1L = 3;
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UCSR1A |= _BV(U2X1); |
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#elif (XBEE_BAUD == 115200) |
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UBRR1H = 0x00;
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UBRR1L = 8;
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UCSR1A |= _BV(U2X1); |
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#elif (XBEE_BAUD == 57600) |
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UBRR1H = 0x00;
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UBRR1L = 16;
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UCSR1A |= _BV(U2X1); |
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#elif (XBEE_BAUD == 38400) |
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UBRR1H = 0x00;
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UBRR1L = 25;
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UCSR1A |= _BV(U2X1); |
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#elif (XBEE_BAUD == 19200) |
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UBRR1H = 0x00;
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UBRR1L = 51;
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UCSR1A |= _BV(U2X1); |
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#elif (XBEE_BAUD == 9600) |
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/* this is the default baud rate, so do nothing
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UBRR1H = 0x00;
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UBRR1L = 103;
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UCSR1A |= _BV(U2X1);*/
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#else //Baud rate is defined in the header file, we should not get here |
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return 0; |
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#endif
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delay_ms(50);
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// enter command mode
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WL_DEBUG_PRINT("entering command mode 2\r\n");
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xbee_send_string("+++");
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xbee_wait_for_ok(); |
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WL_DEBUG_PRINT("entered command mode 2\r\n");
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if (xbee_enter_api_mode() != 0) { |
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WL_DEBUG_PRINT("can't enter api mode\r\n");
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return -1; |
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} |
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WL_DEBUG_PRINT("Entered api mode.\r\n");
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if (xbee_exit_command_mode() != 0) { |
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WL_DEBUG_PRINT("can't exit command mode\r\n");
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return -1; |
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} |
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WL_DEBUG_PRINT("Left command mode.\r\n");
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// get MY address
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if (xbee_send_read_at_command("BD")) { |
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WL_DEBUG_PRINT("can't send BD command\r\n");
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return -1; |
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} |
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WL_DEBUG_PRINT("Getting ATBD rate.\n");
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// get MY address
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if (xbee_send_read_at_command("MY")) { |
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WL_DEBUG_PRINT("can't send my command\r\n");
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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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} |
466 |
|
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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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/**
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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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} |
481 |
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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) { |
486 |
WL_DEBUG_PRINT("Failed to read from xbee.\r\n");
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return -1; |
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} |
489 |
|
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return 0; |
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} |
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#endif
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|
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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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} |
502 |
|
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if (xbee_wait_for_ok() != 0) { |
504 |
return -1; |
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} |
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return 0; |
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} |
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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; |
516 |
} |
517 |
|
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xbee_wait_for_ok(); |
519 |
|
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return 0; |
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} |
522 |
|
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/**
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524 |
* Enter API mode.
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**/
|
526 |
static int xbee_enter_api_mode() |
527 |
{ |
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if (xbee_send_string("ATAP 1\r") != 0) { |
529 |
return -1; |
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} |
531 |
xbee_wait_for_ok(); |
532 |
|
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return 0; |
534 |
} |
535 |
|
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/**
|
537 |
* Exit API mode.
|
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**/
|
539 |
static int xbee_exit_api_mode() |
540 |
{ |
541 |
if (xbee_send_modify_at_command("AP","0") != 0) { |
542 |
return -1; |
543 |
} |
544 |
|
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return 0; |
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} |
547 |
|
548 |
/**
|
549 |
* Wait until the string "OK\r" is received from the XBee.
|
550 |
**/
|
551 |
static int xbee_wait_for_ok() |
552 |
{ |
553 |
return xbee_wait_for_string("OK\r", 3); |
554 |
} |
555 |
|
556 |
/**
|
557 |
* Delay until the specified string is received from
|
558 |
* the XBee. Discards all other XBee data.
|
559 |
*
|
560 |
* ********* Robot often hangs here ****************
|
561 |
*
|
562 |
* @param s the string to receive
|
563 |
* @param len the length of the string
|
564 |
**/
|
565 |
static int xbee_wait_for_string(char* s, int len) |
566 |
{ |
567 |
char* curr = s;
|
568 |
unsigned int i=0; |
569 |
while (curr - s < len) {
|
570 |
WL_DEBUG_PRINT("waiting for string\r\n");
|
571 |
// check if buffer is empty
|
572 |
if (buffer_last != buffer_first) {
|
573 |
char c = arrival_buf[buffer_first++];
|
574 |
if (buffer_first == XBEE_BUFFER_SIZE) {
|
575 |
buffer_first = 0;
|
576 |
} |
577 |
WL_DEBUG_PRINT("buffer char|");
|
578 |
WL_DEBUG_PRINT_CHAR(c); |
579 |
WL_DEBUG_PRINT("|\r\n");
|
580 |
|
581 |
if (c == *curr) {
|
582 |
curr++; |
583 |
} else {
|
584 |
#ifndef ROBOT
|
585 |
//return -1; // Computer is less forgiving.
|
586 |
curr = s; |
587 |
#else
|
588 |
curr = s; |
589 |
#endif
|
590 |
} |
591 |
} // else buffer is empty.
|
592 |
|
593 |
#ifndef ROBOT
|
594 |
usleep(100);
|
595 |
#endif
|
596 |
} |
597 |
if (i >= 10000) |
598 |
return -1; |
599 |
|
600 |
return 0; |
601 |
} |
602 |
|
603 |
/**
|
604 |
* Verifies that the packets checksum is correct.
|
605 |
* (If the checksum is correct, the sum of the bytes
|
606 |
* is 0xFF.)
|
607 |
*
|
608 |
* @param packet the packet received. This includes the first
|
609 |
* three bytes, which are header information from the XBee.
|
610 |
*
|
611 |
* @param len The length of the packet received from the XBee
|
612 |
*
|
613 |
* @return 0 if the checksum is incorrect, nonzero
|
614 |
* otherwise
|
615 |
**/
|
616 |
int xbee_verify_checksum(char* packet, int len) |
617 |
{ |
618 |
unsigned char sum = 0; |
619 |
int i;
|
620 |
for (i = 3; i < len; i++) |
621 |
sum += (unsigned char)packet[i]; |
622 |
return sum == 0xFF; |
623 |
} |
624 |
|
625 |
/**
|
626 |
* Returns the checksum of the given packet.
|
627 |
*
|
628 |
* @param buf the data for the packet to send
|
629 |
* @param len the length of the packet in bytes
|
630 |
*
|
631 |
* @return the checksum of the packet, which will
|
632 |
* become the last byte sent in the packet
|
633 |
**/
|
634 |
char xbee_compute_checksum(char* buf, int len) |
635 |
{ |
636 |
int i;
|
637 |
unsigned char sum = 0; |
638 |
for (i = 0; i < len; i++) |
639 |
sum += (unsigned char)buf[i]; |
640 |
return 0xFF - sum; |
641 |
} |
642 |
|
643 |
/**
|
644 |
* Adds header information and checksum to the given
|
645 |
* packet and sends it. Header information includes
|
646 |
* XBEE_FRAME_START and the packet length, as two bytes.
|
647 |
*
|
648 |
* @param buf the packet data
|
649 |
* @param len the size in bytes of the packet data
|
650 |
*
|
651 |
**/
|
652 |
static int xbee_send_frame(char* buf, int len) |
653 |
{ |
654 |
char prefix[3]; |
655 |
prefix[0] = XBEE_FRAME_START;
|
656 |
prefix[1] = (len & 0xFF00) >> 8; |
657 |
prefix[2] = len & 0xFF; |
658 |
char checksum = xbee_compute_checksum(buf, len);
|
659 |
|
660 |
if (xbee_send(prefix, 3) != 0) { |
661 |
return -1; |
662 |
} |
663 |
|
664 |
if (xbee_send(buf, len) != 0) { |
665 |
return -1; |
666 |
} |
667 |
|
668 |
if (xbee_send(&checksum, 1) != 0) { |
669 |
return -1; |
670 |
} |
671 |
|
672 |
return 0; |
673 |
} |
674 |
|
675 |
/**
|
676 |
* Sends an AT command to read a parameter.
|
677 |
*
|
678 |
* @param command the AT command to send. For exmaple,
|
679 |
* use ID to read the PAN ID and MY to return the XBee ID.
|
680 |
* See the XBee reference guide for a complete listing.
|
681 |
**/
|
682 |
int xbee_send_read_at_command(char* command) |
683 |
{ |
684 |
return xbee_send_modify_at_command(command, NULL); |
685 |
} |
686 |
|
687 |
/**
|
688 |
* Sends the given AT command.
|
689 |
*
|
690 |
* @param command the AT command to send (e.g., MY, ID)
|
691 |
* @param value the value to pass as a parameter
|
692 |
* (or NULL if there is no parameter)
|
693 |
**/
|
694 |
static int xbee_send_modify_at_command(char* command, char* value) |
695 |
{ |
696 |
char buf[16]; |
697 |
int i;
|
698 |
|
699 |
buf[0] = XBEE_FRAME_AT_COMMAND;
|
700 |
buf[1] = 1; |
701 |
buf[2] = command[0]; |
702 |
buf[3] = command[1]; |
703 |
int valueLen = 0; |
704 |
if (value != NULL) |
705 |
{ |
706 |
valueLen = strlen(value); |
707 |
if (valueLen > 8) |
708 |
{ |
709 |
WL_DEBUG_PRINT("AT Command too large.\r\n");
|
710 |
return -1; |
711 |
} |
712 |
|
713 |
for (i = 0; i < valueLen; i++) { |
714 |
buf[4 + i] = value[i];
|
715 |
} |
716 |
} |
717 |
|
718 |
return xbee_send_frame(buf, 4 + valueLen); |
719 |
} |
720 |
|
721 |
/**
|
722 |
* Send the specified packet.
|
723 |
*
|
724 |
* @param packet the packet data to send
|
725 |
* @param len the number of bytes in the packet
|
726 |
*
|
727 |
* @param dest the ID of the XBee to send the packet to,
|
728 |
* or XBEE_BROADCAST to send the message to all robots
|
729 |
* in the PAN.
|
730 |
*
|
731 |
* @param options a combination of the flags
|
732 |
* XBEE_OPTIONS_NONE, XBEE_OPTIONS_DISABLE_RESPONSE and
|
733 |
* XBEE_OPTIONS_BROADCAST_ALL_PANS
|
734 |
*
|
735 |
* @param frame the frame number to associate this packet
|
736 |
* with. This will be used to identify the response when
|
737 |
* the XBee alerts us as to whether or not our message
|
738 |
* was received.
|
739 |
**/
|
740 |
int xbee_send_packet(char* packet, int len, int dest, char options, char frame) |
741 |
{ |
742 |
char buf[5]; |
743 |
char prefix[3]; |
744 |
int i;
|
745 |
unsigned char checksum = 0; |
746 |
|
747 |
if (len > 100) |
748 |
{ |
749 |
WL_DEBUG_PRINT("Packet is too large.\r\n");
|
750 |
return -1; |
751 |
} |
752 |
|
753 |
//data for sending request
|
754 |
buf[0] = XBEE_FRAME_TX_REQUEST_16;
|
755 |
buf[1] = frame;
|
756 |
buf[2] = (dest >> 8) & 0xFF; |
757 |
buf[3] = dest & 0xFF; |
758 |
buf[4] = options;
|
759 |
|
760 |
//packet prefix, do this here so we don't need an extra buffer
|
761 |
prefix[0] = XBEE_FRAME_START;
|
762 |
prefix[1] = ((5 + len) & 0xFF00) >> 8; |
763 |
prefix[2] = (5 + len) & 0xFF; |
764 |
|
765 |
for (i = 0; i < 5; i++) |
766 |
checksum += (unsigned char)buf[i]; |
767 |
for (i = 0; i < len; i++) |
768 |
checksum += (unsigned char)packet[i]; |
769 |
checksum = 0xFF - checksum;
|
770 |
|
771 |
if (xbee_send(prefix, 3) != 0) { |
772 |
return -1; |
773 |
} |
774 |
|
775 |
if (xbee_send(buf, 5) != 0) { |
776 |
return -1; |
777 |
} |
778 |
|
779 |
if (xbee_send(packet, len) != 0) { |
780 |
return -1; |
781 |
} |
782 |
|
783 |
if (xbee_send((char*)&checksum, 1) != 0) { |
784 |
return -1; |
785 |
} |
786 |
|
787 |
return 0; |
788 |
} |
789 |
|
790 |
/**
|
791 |
* Reads a packet received from the XBee. This function
|
792 |
* is non-blocking. The resulting packet is stored in dest.
|
793 |
* Only returns transmission response packets and
|
794 |
* received packets. The returned packet does not include
|
795 |
* header information or the checksum. This method also
|
796 |
* handles special packets dealt with by the XBee library,
|
797 |
* and so should be called frequently while the XBee is in
|
798 |
* use.<br><br>
|
799 |
*
|
800 |
* The first byte of the packet will be either
|
801 |
* XBEE_TX_STATUS or XBEE_RX to indicated
|
802 |
* a response to a sent message or a received message,
|
803 |
* respectively.<br><br>
|
804 |
*
|
805 |
* For a status response packet:<br>
|
806 |
* The first byte will be XBEE_TX_STATUS.<br>
|
807 |
* The second byte will be the frame number.<br>
|
808 |
* The third byte will be the result. 0 indicates success,
|
809 |
* and nonzero indicates that an error ocurred in
|
810 |
* transmitting the packet.<br><br>
|
811 |
*
|
812 |
* For a received packet:<br>
|
813 |
* The first byte will be XBEE_RX.<br>
|
814 |
* The second and third bytes will be the 16-bit
|
815 |
* address of the packet's sender.<br>
|
816 |
* The fourth byte is the signal strength.<br>
|
817 |
* The fifth byte is 1 if the packet were sent to
|
818 |
* a specific address, and 2 if it is a broadcast packet.<br><br>
|
819 |
*
|
820 |
* @param dest set to the packet data
|
821 |
* @return the length of the packet, or -1 if no packet
|
822 |
* is available
|
823 |
**/
|
824 |
int xbee_get_packet(unsigned char* dest) |
825 |
{ |
826 |
int ret;
|
827 |
//start reading a packet with XBEE_FRAME_START
|
828 |
if (currentBufPos == 0) |
829 |
{ |
830 |
do
|
831 |
{ |
832 |
if (buffer_first == XBEE_BUFFER_SIZE)
|
833 |
buffer_first = 0;
|
834 |
// check if buffer is empty
|
835 |
if (buffer_first == buffer_last) {
|
836 |
WL_DEBUG_PRINT("buffer empty\r\n");
|
837 |
return -1; |
838 |
} |
839 |
} while (arrival_buf[buffer_first++] != XBEE_FRAME_START);
|
840 |
|
841 |
if (buffer_first == XBEE_BUFFER_SIZE) {
|
842 |
buffer_first = 0;
|
843 |
} |
844 |
xbee_buf[0] = XBEE_FRAME_START;
|
845 |
currentBufPos++; |
846 |
} |
847 |
|
848 |
int len = -1; |
849 |
if (currentBufPos >= 3) { |
850 |
len = (int)xbee_buf[2] + ((int)xbee_buf[1] << 8); |
851 |
} |
852 |
|
853 |
while (len == -1 //packet length has not been read yet |
854 |
|| currentBufPos < len + 4)
|
855 |
{ |
856 |
if (currentBufPos == 3) |
857 |
{ |
858 |
len = (int)xbee_buf[2] + ((int)xbee_buf[1] << 8); |
859 |
if (len > 120) |
860 |
{ |
861 |
WL_DEBUG_PRINT("Packet too large. Probably error in XBee transmission.\r\n");
|
862 |
currentBufPos = 0;
|
863 |
return -1; |
864 |
} |
865 |
} |
866 |
|
867 |
// check if buffer is empty
|
868 |
if (buffer_first == buffer_last) {
|
869 |
WL_DEBUG_PRINT("Buffer empty 2\r\n");
|
870 |
return -1; |
871 |
} |
872 |
xbee_buf[currentBufPos++] = arrival_buf[buffer_first++]; |
873 |
if (buffer_first == XBEE_BUFFER_SIZE) {
|
874 |
buffer_first = 0;
|
875 |
} |
876 |
} |
877 |
|
878 |
currentBufPos = 0;
|
879 |
|
880 |
if (!xbee_verify_checksum(xbee_buf, len + 4)) |
881 |
{ |
882 |
WL_DEBUG_PRINT("XBee checksum failed.\r\n");
|
883 |
return -1; |
884 |
} |
885 |
|
886 |
//we will take care of the packet
|
887 |
|
888 |
ret = xbee_handle_packet(xbee_buf+3, len);
|
889 |
if (ret == 1) { |
890 |
return 3; |
891 |
} else if (ret == -1) { |
892 |
WL_DEBUG_PRINT("xbee_handle_packet returned -1\r\n");
|
893 |
return -2; |
894 |
} |
895 |
|
896 |
if (dest == NULL) { |
897 |
WL_DEBUG_PRINT("dest buffer is null\r\n");
|
898 |
return -1; |
899 |
} |
900 |
|
901 |
int i;
|
902 |
for (i = 3; i < len + 3; i++) { |
903 |
dest[i - 3] = xbee_buf[i];
|
904 |
} |
905 |
return len;
|
906 |
} |
907 |
|
908 |
/**
|
909 |
* Handles modem status packets.
|
910 |
*
|
911 |
* @param status the type of status packet received.
|
912 |
**/
|
913 |
void xbee_handle_status(char status) |
914 |
{ |
915 |
switch (status)
|
916 |
{ |
917 |
case 0: |
918 |
WL_DEBUG_PRINT("XBee hardware reset.\r\n");
|
919 |
break;
|
920 |
case 1: |
921 |
WL_DEBUG_PRINT("Watchdog timer reset.\r\n");
|
922 |
break;
|
923 |
case 2: |
924 |
WL_DEBUG_PRINT("Associated.\r\n");
|
925 |
break;
|
926 |
case 3: |
927 |
WL_DEBUG_PRINT("Disassociated.\r\n");
|
928 |
break;
|
929 |
case 4: |
930 |
WL_DEBUG_PRINT("Synchronization lost.\r\n");
|
931 |
break;
|
932 |
case 5: |
933 |
WL_DEBUG_PRINT("Coordinator realignment.\r\n");
|
934 |
break;
|
935 |
case 6: |
936 |
WL_DEBUG_PRINT("Coordinator started.\r\n");
|
937 |
break;
|
938 |
} |
939 |
} |
940 |
|
941 |
/**
|
942 |
* Handles AT command response packets.
|
943 |
* @param command the two character AT command, e.g. MY or ID
|
944 |
* @param result 0 for success, 1 for an error
|
945 |
* @param extra the hex value of the requested register
|
946 |
* @param extraLen the length in bytes of extra
|
947 |
**/
|
948 |
static int xbee_handle_at_command_response(char* command, char result, char* extra, int extraLen) |
949 |
{ |
950 |
if (result == 1) |
951 |
{ |
952 |
WL_DEBUG_PRINT("Error with AT");
|
953 |
WL_DEBUG_PRINT(command); |
954 |
WL_DEBUG_PRINT(" packet. Result = ");
|
955 |
switch(result) {
|
956 |
case 1: |
957 |
WL_DEBUG_PRINT("ERROR\r\n");
|
958 |
break;
|
959 |
case 2: |
960 |
WL_DEBUG_PRINT("Invalid Command\r\n");
|
961 |
break;
|
962 |
case 3: |
963 |
WL_DEBUG_PRINT("Invalid Parameter\r\n");
|
964 |
break;
|
965 |
} |
966 |
return -1; |
967 |
} |
968 |
WL_DEBUG_PRINT("AT");
|
969 |
WL_DEBUG_PRINT(command); |
970 |
WL_DEBUG_PRINT(" command was successful.\r\n");
|
971 |
|
972 |
if (command[0] == 'I' && command[1] == 'D') |
973 |
{ |
974 |
xbee_panID = xbee_pending_panID; |
975 |
WL_DEBUG_PRINT("PAN ID set to ");
|
976 |
WL_DEBUG_PRINT_INT(xbee_panID); |
977 |
WL_DEBUG_PRINT(".\r\n");
|
978 |
return 0; |
979 |
} |
980 |
|
981 |
if (command[0] == 'C' && command[1] == 'H') |
982 |
{ |
983 |
xbee_channel = xbee_pending_channel; |
984 |
WL_DEBUG_PRINT("Channel set to ");
|
985 |
WL_DEBUG_PRINT_INT(xbee_channel); |
986 |
WL_DEBUG_PRINT(".\r\n");
|
987 |
return 0; |
988 |
} |
989 |
|
990 |
if (command[0] == 'N' && command[1] == 'D') |
991 |
{ |
992 |
WL_DEBUG_PRINT("ND - extra=");
|
993 |
WL_DEBUG_PRINT(extra); |
994 |
WL_DEBUG_PRINT("\r\n");
|
995 |
return 0; |
996 |
} |
997 |
|
998 |
if (command[0] == 'B' && command[1] == 'D') |
999 |
{ |
1000 |
WL_DEBUG_PRINT("BD - extra=");
|
1001 |
WL_DEBUG_PRINT(extra); |
1002 |
WL_DEBUG_PRINT("\r\n");
|
1003 |
return 0; |
1004 |
} |
1005 |
|
1006 |
if (command[0] == 'M' && command[1] == 'Y' && extraLen != 0) |
1007 |
{ |
1008 |
xbee_address = 0;
|
1009 |
int i;
|
1010 |
for (i = 0; i < extraLen; i++) { |
1011 |
xbee_address = (xbee_address << 8) + extra[i];
|
1012 |
} |
1013 |
|
1014 |
WL_DEBUG_PRINT("XBee address is ");
|
1015 |
WL_DEBUG_PRINT_INT(xbee_address); |
1016 |
WL_DEBUG_PRINT(".\r\n");
|
1017 |
|
1018 |
if (xbee_address == 0) |
1019 |
{ |
1020 |
WL_DEBUG_PRINT("XBee 16-bit address must be set using ATMY.\r\n");
|
1021 |
#ifndef ROBOT
|
1022 |
exit(0);
|
1023 |
#endif
|
1024 |
} |
1025 |
} |
1026 |
return 0; |
1027 |
} |
1028 |
|
1029 |
/**
|
1030 |
* Attempts to handle the packet if it is dealt with
|
1031 |
* by the library.
|
1032 |
* We will handle the following packet types:
|
1033 |
* Modem Status
|
1034 |
* AT Command Response
|
1035 |
*
|
1036 |
* @param packet the packet to handle
|
1037 |
* @param len the length of the packet
|
1038 |
*
|
1039 |
* @return 1 if we have handled the packet, 0 otherwise
|
1040 |
*/
|
1041 |
static int xbee_handle_packet(char* packet, int len) |
1042 |
{ |
1043 |
|
1044 |
char command[3] = {1, 2, 3}; |
1045 |
if (len <= 0) //this should not happend |
1046 |
{ |
1047 |
WL_DEBUG_PRINT("Non-positive packet length.\r\n");
|
1048 |
return 0; |
1049 |
} |
1050 |
|
1051 |
switch ((unsigned char)packet[0]) //packet type |
1052 |
{ |
1053 |
case XBEE_FRAME_STATUS:
|
1054 |
xbee_handle_status(packet[1]);
|
1055 |
return 1; |
1056 |
case XBEE_FRAME_AT_COMMAND_RESPONSE:
|
1057 |
command[0] = packet[2]; |
1058 |
command[1] = packet[3]; |
1059 |
command[2] = 0; |
1060 |
if (xbee_handle_at_command_response(command, packet[4], packet + 5, len - 5) != 0) |
1061 |
return -1; |
1062 |
else
|
1063 |
return 1; |
1064 |
} |
1065 |
return 0; |
1066 |
} |
1067 |
|
1068 |
/**
|
1069 |
* Sets the personal area network id.
|
1070 |
*
|
1071 |
* @param id the new personal area network (PAN) id
|
1072 |
**/
|
1073 |
int xbee_set_pan_id(int id) |
1074 |
{ |
1075 |
char s[3]; |
1076 |
s[0] = (id >> 8) & 0xFF; |
1077 |
s[1] = id & 0xFF; |
1078 |
s[2] = 0; |
1079 |
xbee_pending_panID = id; |
1080 |
return xbee_send_modify_at_command("ID", s); |
1081 |
} |
1082 |
|
1083 |
/**
|
1084 |
* Get the PAN ID for the XBee.
|
1085 |
*
|
1086 |
* @return the personal area network id, or
|
1087 |
* XBEE_PAN_DEFAULT if it has not yet been set.
|
1088 |
**/
|
1089 |
unsigned int xbee_get_pan_id() |
1090 |
{ |
1091 |
return xbee_panID;
|
1092 |
} |
1093 |
|
1094 |
/**
|
1095 |
* Set the channel the XBee is using.
|
1096 |
*
|
1097 |
* @param channel the channel the XBee will not use,
|
1098 |
* between 0x0B and 0x1A
|
1099 |
*
|
1100 |
* @see xbee_get_channel
|
1101 |
**/
|
1102 |
int xbee_set_channel(int channel) |
1103 |
{ |
1104 |
if (channel < 0x0B || channel > 0x1A) |
1105 |
{ |
1106 |
WL_DEBUG_PRINT("Channel out of range.\r\n");
|
1107 |
return -1; |
1108 |
} |
1109 |
|
1110 |
char s[3]; |
1111 |
s[0] = channel & 0xFF; |
1112 |
s[1] = 0; |
1113 |
xbee_pending_channel = channel; |
1114 |
|
1115 |
return xbee_send_modify_at_command("CH", s); |
1116 |
} |
1117 |
|
1118 |
/**
|
1119 |
* Returns the channel which the XBee is currently using.
|
1120 |
*
|
1121 |
* @return the channel the XBee is using
|
1122 |
*
|
1123 |
* @see xbee_set_channel
|
1124 |
**/
|
1125 |
int xbee_get_channel(void) |
1126 |
{ |
1127 |
return xbee_channel;
|
1128 |
} |
1129 |
|
1130 |
/**
|
1131 |
* Get the 16-bit address of the XBee.
|
1132 |
* This is used to specify who to send messages to
|
1133 |
* and who messages are from.
|
1134 |
*
|
1135 |
* @return the 16-bit address of the XBee.
|
1136 |
**/
|
1137 |
unsigned int xbee_get_address() |
1138 |
{ |
1139 |
return xbee_address;
|
1140 |
} |
1141 |
|
1142 |
#ifndef ROBOT
|
1143 |
void xbee_set_com_port(char* port) |
1144 |
{ |
1145 |
xbee_com_port = port; |
1146 |
} |
1147 |
#endif
|
1148 |
|
1149 |
/**@} **/ // end xbee group |
1150 |
|