[Thumbgps-devel] Build vs. modify vs. what should we be doing anyway?

[tz]

On Mon, Mar 12, 2012 at 5:03 PM, Eric S. Raymond <esr at thyrsus.com> wrote:

> Reason #2 is that it's probably a single-layer board (can't think of
> any reason they'd have gone multilayer for a simple interconnect like
> this).  Which in turn means we may very well be able to
> reverse-engineer a workable PCB design and parts list just by looking
> at this thing.

The board is probably minimum 4 layer.

Every USB chip and every GPS chip I've seen in dongles are fine-pitch
surface mount.

You CANNOT do this with anything less than 2 layers with lots of vias,
and if the pitch is fine enough you will need at least 4.

Also the RF section for the GPS - antenna to the input - is critical.
You aren't just going to put some copper out there and have it work
well.

http://www.prolific.com.tw/eng/downloads.asp?ID=23

The prolific is 28 pin ssop with scattered power and ground pins.

GPS chips (except for highly integrated modules) are worse as far as
the pins you need to get to the right places.