DS2.h

00001 #ifndef DS2_H
00002 #define DS2_H
00003 
00004 #include "mbed.h"
00005 
00006 #include "Bus.h"
00007 
00008 extern Serial dbg;
00009 
00010 #define DS2_MTU (127)
00011 
00012 static const char DS2_IDENTIFY[] = {0x00};
00013 
00014 /*
00015 a ds2 packet looks like this:
00016 {0xAA, 0xAA, 0xLL, 0xDD, 0xCC}
00017 or this:
00018 {0xAA, 0xLL, 0xDD, 0xCC}
00019 AA = module address
00020 LL = packet length
00021 DD = data
00022 CC = checksum
00023 there can be either one or two AA module address bytes
00024 there can be 1 or more DD data bytes
00025 
00026 here is an example query packet:
00027 {0x12, 0x04, 0x00, 0x16} (query DME for identification)
00028 the address is a one-byte address of 0x12 (DME)
00029 the packet length is 0x04 bytes
00030 the one byte data payload is 0x00 (identify module)
00031 the xor checksum of the entire packet is 0x16
00032 
00033 the reply would look like this:
00034 {0x12, 0x10, ... 0x??} (DME responding...)
00035 the one byte address is 0x12 (DME)
00036 the packet length will be 0x10 bytes
00037 the xor checksum 0x?? would depend on the missing data "..."
00038 
00039 the same query packet would look like this with two address bytes:
00040 {0x12, 0x00, 0x05, 0x00, 0x17}
00041 
00042 it seems that some modules want one address byte and some want two
00043 either that or it's an extra length byte we're dealing with
00044 probably it's a length byte, but I'll worry about it when I find out
00045 */
00046 class DS2Packet
00047 {
00048     unsigned short* address;
00049     char* length;
00050     char* data;
00051     char* checksum;
00052     
00053     char* rawdata;
00054     bool has8BitAddr;
00055 
00056     void updateChecksum();
00057     
00058 public:
00059     DS2Packet(int maxlength);
00060     DS2Packet(int address, const char* data, int length);
00061     ~DS2Packet();
00062     
00063     void has8BitAddress(bool b);
00064     
00065     bool has8BitAddress()
00066     {
00067         return has8BitAddr;
00068     }
00069     
00070     int getAddress()
00071     {
00072         if(has8BitAddr)
00073             return *address >> 8 & 0xff;
00074         return *address;
00075     }
00076     
00077     int getLength()
00078     {
00079         return *length;
00080     }
00081     
00082     char* getData()
00083     {
00084         return data;
00085     }
00086 
00087     int getChecksum()
00088     {
00089         char* check = rawdata + *length - 1;
00090         return *check;
00091     }
00092     
00093     char* getRawData()
00094     {
00095         return rawdata;
00096     }
00097 };
00098 
00099 class DS2
00100 {
00101     Bus *k;
00102     Bus *l;
00103     
00104 public:
00105     DS2(Bus* KLine, Bus* LLine);
00106     ~DS2();
00107     int sendPacket(DS2Packet* packet, Bus* bus);
00108     DS2Packet* getPacket(Bus* bus);
00109     DS2Packet* getPacket8(Bus* bus);
00110     bool test();
00111     void testModule(int address);
00112     void snoop();
00113 
00114 };
00115 
00116 #endif //DS2_H