Joined: April 2002
||Posted: April 30 2002,3:50 am
This sounds reassuring.....
I've just purchased a new Meridian GPS and was wondering whether I could
edit the hex file to change the text - sounds like I can. I was worried
they might have a hidden checksum (ie other than the one mentioned) to stop
the software running at all if it was modified.
I've also managed to find where the icons are stored, I plan to change these
from the standard US to something more useful for my application, such as
orienteering markers or some such.
They are 2 bit colour (ie there are 4 'colours', black/transparent is 00, white is 11,
and two grey shades), and 13x13 in size (actually 11x11 with a black
border). From the way they are stored (turned through 90 degrees), the
screen is probably addressed from the bottom left and also rotated through 90
degrees. They have stored the normal icons and the inverted (selected
items) seperately, one set follows the other.
There seems to be a 16 byte header to each icon, I don't know what this is
(has anybody out there worked it out?) but the hex is very similar for each
one, it is only changed by a couple of bits each time.
For instance, the hex for the standard waypoint icon looks like this:
00 00 00 3F
00 0C 00 3F
00 0C 00 3F
03 FF F0 3F
03 0C 30 3F
They haven't used the grey values for any icons, just black and white. Note
every line ends in 3F, this is because the 13th pixel is always black, and
they have padded out the last byte of each line with 1s.
I'll let you know if I get this to work - I haven't tried it yet.....and if
anyone fancies writing some code........