PSP News

August 1st, 2006, 01:52 Posted By: A Fn NOOB

Inspired by 'Deniska', I decided to make a cable to interface a GPS reciever I had collecting dust for some time. Its the Pharos GPS-360 with Microsoft branding; packaged with Streets & Trips 2005. It uses the SIRF-II chip, and communicates with the PSP at the same voltage (2.5V), and (default) protocol (4800 8N1 TTL) as the PSP. These units can be found new and used for dirt cheap

From the research I have done, any GPS can be interfaced with the PSP. Some units however would require more hardware/software modifications than the SIRF-II based GPS recievers.

If anyone has any questions on the particulars of how to do this, I will happily post more details of the pinouts, and the version of deniska's GPS-Viewer that I compiled to work with 4800-baud GPS units. (By far the most common speed)

Pin 1 RXD
Pin 2 GND--------------------------{}-------> Pin 2 on PSP
Pin 3 TXD--------------------------{}-------> Pin 6 on PSP
Pin 4 GND--------------------------{}-------> Pin 2 on PSP
Pin 5 VCC<--(3.5-5.5VDC input<-
Pin 6 Unused |
|
Battery + ---------------------------|
Battery - ------------------------{}-------> Pin 1 on PSP

Never use wire colors. I think that some mfgrs switch up the
colors to f*** with people. For instance, my PSP remote
cable's wire colors do not correspond to the ones at lua.org,
or any other place Ive seen. Youve got to use an ohmmeter or
whip up a simple continuity tester with a battery and light
bulb, so that you can write down which color wire goes to
which pin.

Im just going to tell you how I powered the GPS, although
there are several ways to achieve the same result. (You could
power it from the PSP battery if you wanted to, but not from
the serial port as it only supplies 2.5V DC)
http://i89.photobucket.com/albums/k2..._NOOB/psp2.jpg

I used DB9 serial connectors (Like the ones on a joystick port
from an Atari 2600 or Commodore Vic 20/ 64) and connected all
the wires from the PSP to a female DB9. I then took my 4 wires
from the GPS and hooked in TXD and GND, GND to a male DB9. I
wired a Motorola Lithium battery from an old cell phone (2 yrs
old is OLD for a cell phone nowdays eh?) to feed VCC on GPS.
The negative from the battery can be hooked to your other
grounds (pins 2 & 4 @ GPS,to 2 on PSP). What I did, however,
is wire "-" from the battery to PIN 1 of the PSP. This
way,the GPS is only powered when the connector is plugged in
to the PSP and not powered all the time.
I suspect there may be a way to turn power on and off via
software but not sure yet. (By interrupting GND)
Another reason for the Moto battery is that it's very
thin,rechargeable,and has an embedded protection circuit on a
little PCB inside. (dont ever throw away any old electronics)
I couldve done a neater job with this cable but its sturdy.
If you dont want to cut up your USB cable for the GPS, do a
search on "Jornada" I think it is, its a PDA that uses the
same connector, I got one from a site called Gomadic, but that
was 2 yrs ago or so. Id like to find some of these PSP serial
connectors somewhere.

I soldered all the wires to the db9 connectors, and used a bunch of heat shrink tubing to keep the wires from shorting to each other. You could make a dedicated connector if you cut up a psp-remote cable and a "Jornada" connector.... but soldering the wires is the only way its going to hold up under any stress at all.

It seems like a lot of people have a phobia about using soldering irons. Just buy one and practice on some old electronics by desoldering components and soldering them back up. Theres plenty of material on the internet about how to solder.

And you dont have to solder anything on your PSP, or GPS, its just at the cables. [And no resistors]

Thats the piece going from the PSP-remote connector to a DB9. It has a shield, and I beefed up the white cable by putting heat shrink tubing over the wire and the molded plastic "shoulder". The shield has a clamp inside to keep the wire from pulling out.

I havent put a shield on the other wire going to the GPS & battery because Im am going to make a multipurpose connector in an Altoids tin so that I can interface the PSP with other serial devices, and also have the Motorola battery supply power to the PSP if needed.
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