Orca Robotics

00001 /*
00002  * Orca-Robotics Project: Components for robotics 
00003  *               http://orca-robotics.sf.net/
00004  * Copyright (c) 2004-2008 Alex Brooks, Alexei Makarenko, Tobias Kaupp
00005  *
00006  * This copy of Orca is licensed to you under the terms described in
00007  * the LICENSE file included in this distribution.
00008  *
00009  */
00010 
00011 #ifndef ORCA_SEGWAY_RMP_CAN_PACKET_H_
00012 #define ORCA_SEGWAY_RMP_CAN_PACKET_H_
00013 
00014 #include <sys/types.h>
00015 #include <stdint.h>
00016 #include <string.h>
00017 
00018 namespace segwayrmpacfr
00019 {
00020 
00021 /*
00022   CAN Packets consist of:
00023     - Header (2 bytes in standard packet (which the RMP always uses))
00024     - Data Length Code (2 bytes, always '8' for RMP)
00025     - Data (8 bytes, split into 4 2-byte slots)
00026 
00027   Even if we're interfacing with USB, we still pass CAN packets
00028   (wrapped up in USB packets).
00029 
00030   @note This code originates from Player/Stage project
00031   http://playerstage.sf.net, file: canio.h
00032   @author Alex Makarenko
00033 */
00034 class CanPacket
00035 {
00036 public:
00037 
00038     // Always use all 8 bytes
00039     static const int CAN_DATA_SIZE = 8;
00040 
00041     CanPacket( uint32_t id=0 );
00042     
00043     // Sets the ID (what the RMP docs call the header)
00044     void setId( uint32_t id ) { id_ = id; }
00045 
00046     // RMP has fixed-size messages
00047     const uint16_t dataLengthCode() { return 0x0008; }
00048 
00049     // returns the value of the slotNum'th slot
00050     uint16_t getSlot(int slotNum) const;
00051 
00052     // sets the slotNum'th slot to val
00053     void putSlot(const int slotNum, const uint16_t val);
00054     
00055     // The id is the 'header' field in the RMP docs
00056     uint32_t id() const { return id_; }
00057 
00058     // Allow direct access for memcpy
00059     uint8_t *msg() { return msg_; }
00060     const uint8_t *msg() const { return msg_; }
00061 
00062     // Human-readable string for debugging
00063     char* toString() const;
00064 
00065 private:
00066 
00067     long id_;
00068     uint8_t msg_[CAN_DATA_SIZE];
00069 
00070     // Could store dataLengthCode and flags here,
00071     // but don't bother cause for the RMP they're always the same.
00072     //    uint32_t dlc;
00073     //    uint32_t flags;
00074 
00075 };
00076 
00077 //
00078 // Some functions for building CAN packets
00079 // (all values are in the RMP's native representation)
00080 //
00081 
00082 CanPacket
00083 statusCommandPacket( uint16_t statusCommandType, 
00084                      uint16_t value,
00085                      int16_t  speedCount,
00086                      int16_t  turnrateCount );
00087 
00088 CanPacket
00089 motionCommandPacket( int16_t speedCount,
00090                      int16_t turnrateCount );
00091 
00092 CanPacket
00093 shutdownCommandPacket();
00094 
00095 } // namespace
00096 
00097 #endif
canpacket.h
