Re: [uracoli-devel] Timestamp in uracoli sniffer

[Axel Wachtler]

Hallo Martin, 

First question is, is your data stream aligned correctly, e.g. are you picking 
the right bytes.

Both AVR and PC handles the data little endian, 
 >>> struct.pack("L", 0xaabbccdd) => '\xdd\xcc\xbb\xaa'
so the formula seems correct.
> int sec = ((int)b[4] << 24 | (int)b[3] << 16 | (int)b[2] << 8 | (int)b[1]);

One option to debug this issue is: use the python PacketCapture application 
and run it with the -vvv option in the command line. In the terminal you will 
get the dump of the serial line packets as hex string, and in wireshark you 
can see, how the data are decoded.

e.g. if the terminal dumps:

0xf3:0x51:0xc8:0x4d:0x44:0xa6:0xa:0x0:0x5b:0x0:0x0:0x0:0x5b:0x0:0x0:0x0:0x41
:0x88:0x1:0xfe:0xca:0x34:0x12:0x5:0x0:0x61:0x64:0x64:0x72:0x3d:0x30:0x78:0x35:0x
2c:0x20:0x76:0x6d:0x63:0x75:0x3d:0x33:0x30:0x30:0x30:0x2c:0x20:0x73:0x68:0x74:0x
5f:0x74:0x3d:0x32:0x35:0x38:0x37:0x32:0x2c:0x20:0x73:0x68:0x74:0x5f:0x72:0x68:0x
3d:0x33:0x33:0x36:0x30:0x36:0x2c:0x20:0x61:0x63:0x63:0x3d:0x5b:0x31:0x34:0x2c:0x
32:0x2c:0x37:0x34:0x5d:0xa:0xd:0x0:0x0:0x0:0x0:0x0:0x0:0x0:0x0:0x0:0x0:0x0:0x0:0
x0:0x0:0x0:0x0:0x0:0xdd:0x1e

with:
      chan : 17
     clist : [11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26]
     crate : OQPSK250
  platform : stb230 V0.1
      port : /dev/ttyUSB0
     rates : OQPSK250
    ticknb : 65536
    tscale : 1.25e-07
      type : port


So 0xf3:0x51:0xc8:0x4d:0x44:0xa6:0xa:0x0: are the timestamp bytes and they 
need to be represented as 1304973811 seconds since 1.1.1970

If needed, you can even write more debug prints in the python code.

Hope this helps, Axel