*Wired* GPS on 700p

Discussion of the 700p.

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KevinAndrewLipscomb
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*Wired* GPS on 700p

Post by KevinAndrewLipscomb » Mon Jan 01, 2007 12:58 pm

I've been using a wired GPS setup since my Kyocera 7135 days. I have a basic GPS receiver whose signal cable terminates in a 9-pin RS-232 connector. I have a cable from pcables.com that converts from the 9-pin to (nowadays) a Treo 650/700 connector. I ran Quo Vadis, then TomTom on the Treo. This all worked great.

Then, with the Kyocera 7135, I applied a ROM update from Sprint, and afterward the 7135 would not recognize that the GPS receiver was there. But my laptop would.

By then, the 650 was the s***, so I bought one and again, my wired GPS setup worked fantastically. Then I applied the Verizon 1.05a ROM update, and again my device would not recognize that the GPS was there. But my laptop would.

By then (again -- see a pattern here?), the 700p was current, so I bought one and -- CRAP! -- when I plug the GPS in, I get a once-per-second popup that says "Cleaning up DUN connection". When I run a nav program (TomTom), I get "No GPS device". Yet the laptop still interfaces fine with the wired GPS receiver.

Shouldn't this work? It's just standard NMEA data coming across the serial port. Why does the 700p think the DUN connection needs to be cleaned up? Is there any way to tell DUN to butt out? Has Palm silently dropped all support for wired serial connections? That would seem hard to believe. And is there any diagnostic software out there that I can use to get more information about the status of the wired serial port, and/or what the Palm is seeing when I hook up my wired GPS?

Please help me! I don't want to spend another $75-$250 for another GPS solution.

(Shadwomite: I do see a potential application here for that wierd ECYPH device from pcables.com that you asked about. But still, that's $99 I shouldn't have to spend.)
-- Kevin Andrew Lipscomb
-- http://kal.webhop.net

KevinAndrewLipscomb
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Post by KevinAndrewLipscomb » Sun Jan 14, 2007 5:10 am

I've searched all the PRC files in my Backup folder, and I still can't identify where the "Cleaning up DUN connection" message is coming from. I don't have the ROM images to search through. Can someone let me know what is generating that message?

I use the "strings" utility in the binutils package from Cygwin to extract strings from binary files.
-- Kevin Andrew Lipscomb
-- http://kal.webhop.net

kocoman
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Joined:Sat Oct 21, 2006 7:15 am

Post by kocoman » Tue Jan 16, 2007 12:56 pm

Its in your 700p rom

MRFt
applrfsL
tAIN
tFRM
tFRM
Live Mode
Please wait
Desktop operation in progress...
Please wait
Cleaning up the DUN Connection...
LiveModeApp-rfsL_esES
ylvoLsfr
ylvo
NIAt
MRFt
MRFt
applrfsL
tAIN
tFRM

KevinAndrewLipscomb
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Post by KevinAndrewLipscomb » Tue Jan 16, 2007 3:27 pm

Any idea which file in the ROM?
-- Kevin Andrew Lipscomb
-- http://kal.webhop.net

kocoman
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Post by kocoman » Tue Jan 16, 2007 4:00 pm

I only got a rom dump (of my treo 700p) but how to extract the files from it I don't know.
Its in this file: LiveModeApp-rfsL_enUS.prc

LiveModeApp-rfsL_enUS.prc
----------------------------------------------------
LiveModeApp-rfsL_enUS
ovlyrfsL
ovly
xtAIN
tFRM
tFRM
applrfsL
tAIN
tFRM
tFRM
7Live Mode
Please wait
Desktop operation in progress...
Please wait
Cleaning up the DUN Connection...
-----------

my (copy from someone script)
#!/bin/bash
#ext=".3gp" #put the file extension here

for f in * #repeats of for each file in the directory
do
#extract the filename without extension
#base=`basename $f`
echo $f >> ~/tet1
echo "----------------------------------------------------" >> ~/tet1
#extract the prefix

strings $f >> ~/tet1

#extract date and time
#dtime=`echo $base | cut -c 14-25 -`
#echo $dtime
done

eeprom7777
PDAPhone Hacker Team
Posts:11
Joined:Sat Apr 30, 2005 1:22 pm

Re: *Wired* GPS on 700p

Post by eeprom7777 » Thu Feb 01, 2007 10:31 am

KevinAndrewLipscomb wrote:...
I have a basic GPS receiver whose signal cable terminates in a 9-pin RS-232 connector. ...
... Yet the laptop still interfaces fine with the wired GPS receiver. ...

Shouldn't this work? It's just standard NMEA data coming across the serial port. ...
No, It shouldn't work. However, if you are very lucky.. it may. Actually a major problem here is although we'd like to believe that is a RS-232 serial port on the bottom connector of device, it is not actually. It is really just serial port signaling (TTL/CMOS level). The hardware needed to drive a RS-232 serial line is not in the device. This dictates that a serial connector to plug into the bottom connector of 700p would have to have a RS-232 Transciever chip (such as a MAX232) or independent serial line driver/reciever chips (such as DS1488, DS1489). These chips can properly convert the high level RS-232 signaling present on the serial line into the low level signaling the device requires. Without the additional hardware, the device is not designed to drive a RS-232 serial line *directly*.

I made a serial cable work on my 700p by adding a 5v supply and a 1489 quad line reciever chip. This chip has 4 serial line reciever circuits and is well suited for the task. The reciever chip is meant to convert high level serial signals down to low level signaling that the device needs. Using a 2nd reciever circuit pointed towards the serial line works also (assuming your not trying to drive a 250' serial cable) as the signal output is very clean and easy for a transciever chip in pc to lock onto. The primary concern here is protecting the device from high level signaling present on a RS-232 line. Internal to the device the serial port is fed out through gpio's. The maximum gpio voltage is 3.3v (and the gpio outputs are not designed to sink the necessary current for proper serial line driving). You should power your reciever circuit with 5v or a little less to keep your 700 safe from too high of signal levels. I highly recommend Not hitting the device with the voltages that may be present on a RS-232 serial line (directly).

I'm not sure what your serial cable has built in... but short of having the proper circuitry (RS-232 interface)... I would highly doubt that it will work.

KevinAndrewLipscomb
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Post by KevinAndrewLipscomb » Thu Feb 01, 2007 11:57 am

Hey, thanks for the explanation, I really appreciate it. Does anyone offer a cable with the required elements? I've checked the pcables.com site, but I have a hard time decoding their literature.
-- Kevin Andrew Lipscomb
-- http://kal.webhop.net

eeprom7777
PDAPhone Hacker Team
Posts:11
Joined:Sat Apr 30, 2005 1:22 pm

Post by eeprom7777 » Fri Feb 02, 2007 8:29 am

I dont see exactly what you need at pc cables dot com either.
Here is a link to a cable that solves the level issues.
http://www.digitalnemesis.com/products/ ... sheet.aspx
However you still need to power this cable somehow.
After some searching, this issue seems common to robot boards, pic microcontrollers and even some bar code scanners.
The best solution for you I believe would be to rob power from the gps cable/device somehow..
Here is a link where they show how to power the needed circuit from a std. rs232 port (using a max233 chip).
http://www.zero-soft.com/HW/RS232/
You can also google 'rs232 ttl level' to find more info.
That last link basically shows how to build it yourself for about $5.00 (vs. about $80.00 for custom cable).
Your best solution will likely depend on your electonic/hacking skills, and the specifics of your gps, connection cable, etc..

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