Unterschiede zwischen den Revisionen 24 und 25

Protocol

The protocol is based on individual serial data frames that are organized as shown in the following table.

Start-Byte

Address-Byte

ID-Byte

n Data-Bytes coded

CRC-Byte1

CRC-Byte2

Stop-Byte

'#'

variable

'V','D' etc

"modified-base64"

variable

variable

'\r'

Commands

The Commands based on the dataframes above are listed [:en/SerialCommands:here]

Slave Adresses

Since Navi 0.12h FC 0.71f Mag 0.19 there are constant SlaveAdresses:

Slave-Address

Part

1

FC

2

NC

3

MK3MAG

Data Format

Have a look into the Functions Decode64 and SendOutData in uart.c of the FC Firmware to see how the Data is encoded and decoded:

   1 void SendOutData(unsigned char cmd,unsigned char modul, unsigned char *snd, unsigned char len)
   2 {
   3  unsigned int pt = 0;
   4  unsigned char a,b,c;
   5  unsigned char ptr = 0;
   6 
   7  SendeBuffer[pt++] = '#';               // Start-Byte
   8  SendeBuffer[pt++] = modul;             // Adress 
   9  SendeBuffer[pt++] = cmd;                // Command
  10 
  11  while(len)
  12   {
  13    if(len) { a = snd[ptr++]; len--;} else a = 0;
  14    if(len) { b = snd[ptr++]; len--;} else b = 0;
  15    if(len) { c = snd[ptr++]; len--;} else c = 0;
  16    SendeBuffer[pt++] = '=' + (a >> 2);
  17    SendeBuffer[pt++] = '=' + (((a & 0x03) << 4) | ((b & 0xf0) >> 4));
  18    SendeBuffer[pt++] = '=' + (((b & 0x0f) << 2) | ((c & 0xc0) >> 6));
  19    SendeBuffer[pt++] = '=' + ( c & 0x3f);
  20   }
  21  AddCRC(pt);
  22 }
  23 
  24 void Decode64(unsigned char *ptrOut, unsigned char len, unsigned char ptrIn,unsigned char max) 
  25 {
  26  unsigned char a,b,c,d;
  27  unsigned char ptr = 0;
  28  unsigned char x,y,z;
  29  while(len)
  30   {
  31    a = RxdBuffer[ptrIn++] - '=';
  32    b = RxdBuffer[ptrIn++] - '=';
  33    c = RxdBuffer[ptrIn++] - '=';
  34    d = RxdBuffer[ptrIn++] - '=';
  35    if(ptrIn > max - 2) break;     // dont process more data than recieved
  36 
  37    x = (a << 2) | (b >> 4);
  38    y = ((b & 0x0f) << 4) | (c >> 2);
  39    z = ((c & 0x03) << 6) | d;
  40 
  41    if(len--) ptrOut[ptr++] = x; else break;
  42    if(len--) ptrOut[ptr++] = y; else break;
  43    if(len--) ptrOut[ptr++] = z; else break;
  44   }
  45 
  46 }

$/!\$ ToDo: describe data-format

Checksum

   1 unsigned int tmpCRC = 0; 
   2 for(int i = 0; i <  DataBufferLength;i++)
   3  { 
   4   tmpCRC += DataBuffer[i]; 
   5  }   
   6 tmpCRC %= 4096; 
   7 CRC1 = '=' + tmpCRC / 64; 
   8 CRC2 = '=' + tmpCRC % 64;

$/!\$ ToDo: describe checksum calculation verbaly

Implementations

Sometimes its a lot more easy to look at code rather than reather than to look at Specifications/Documentation:
uart.c in the Flight-Ctrl Firmware ( C )
MKCommunicator.java from ["DUBwise"] ( Java / J2ME )
mktool.cpp @ ["QMKGroundStation"] ( C++ )
GroundStation ( LabView )

Start-Byte	Address-Byte	ID-Byte	n Data-Bytes coded	CRC-Byte1	CRC-Byte2	Stop-Byte
'#'	variable	'V','D' etc	"modified-base64"	variable	variable	'\r'

Slave-Address	Part
1	FC
2	NC
3	MK3MAG

Protocol

Commands

Slave Adresses

Data Format

Checksum

Implementations

Links