
In case you don't own the actual GPS receiver (Lassen SK II board)
but want to test the system by sending dummy GPS data from a PC to
the GBC through the serial port, here's a little explanation of
what the software is expecting to receive:


- Serial communication must be 9600 bps, parity odd, 1 stop bit.


- After turning on the GBC, the program will check the receiver's activity
by waiting for a couple of periodical data packets. You must send a byte
string (any length and values will do to cheat it), then wait for around
one second and send some consecutive bytes again.


- If you did it right, the GBC will then send the following data string
to try to configurate the receiver protocol (in hexadecimal):

        10 BC 00 07 07 03 01 00 00 01 01 00 10 03


- From now on, the program expects to communicate using an ASCII protocol
called TAIP. Every TAIP message is delimited by '>' and '<' characters.
Firstly, it will send another configuration message:

    >FPV00000000<

You don't need to care about this. Next, it will send the following message:

    >QVR<

Now you must send some consecutive bytes in response (again, it won't care
about its values).


- If everything went all right, the program will enter the main loop and
will request GPS data from the receiver at about 1 second intervals.
Data is requested by using four types of TAIP messages. Here's how you must
answer to them every time you receive them (message length must be EXACTLY
as shown):

------------------------------------------------------------------------------

    Request:    >QST<
    Response:   >RST00015A0200;*00<

------------------------------------------------------------------------------

    Request:    >QAL<
    Response:   >RAL00000aaaaaabbbb12;*00<
                                                where   aaaaaa = altitude
                                                        bbbb = vertical speed

            Example:  >RAL00000+01520+02512;*00<

                        (1520m above mean sea level / 25 mph upwards)

------------------------------------------------------------------------------

    Request:    >QPV<
    Response:   >RPV00000aaaaaaaabbbbbbbbbcccddd12;*00<

                                                where   aaaaaaaa = latitude
                                                        bbbbbbbbb = longitude
                                                        ccc = speed
                                                        ddd = heading

            Example:  >RPV00000+3423567+0147654302700512;*00<

                        (34.23567 degs north / 14.76543 degs east /
                         27mph / 5 degs from N eastwardly)

------------------------------------------------------------------------------

    Request:    >QTM<
    Response:   >RTMaaaabbbbbcccccccc00104100000;*00<

                                                where   aaaa = hour & minutes
                                                        bbbbb = seconds
                                                        cccccccc = date

            Example:  >RTM1345230000601199000104100000;*00<

                        (13:45:23.000s / 06-01-1990)

------------------------------------------------------------------------------


- HINT: The map of Seville (Spain) will appear on screen when coordinates
  range the following values:

        Latitude:   +37.34378  to  +37.42755

        Longitude:  -006.00713  to  -005.94332


