Implement Report Packet 0x58: Satellite System Data

[mjuenema]

Report Packet 0x58 has a variable structure depending on field 1 ("Type of data"). Currently the code simply raises NotImplementedError.

tsip/structs.py, line 144

class Struct0x58(object):
    def pack(self, *f):
        raise NotImplementedError

    def unpack(self, s):
        raise NotImplementedError

It is probably not necessary to implement Struc0x58.pack().

[mjuenema]

• Byte 0 must be 2 (Data Out) or 3 (No Data)
• Only some GPS may set byte 0 to 3 (No Data) so Byte 3 (Length) must be checked.
• Byte 3 (Length) of Report Packet 0x58 may be 0 if no data was available.