Pmb-648

al.arduengo

I purchased a PMB-648 recently and am having some issues. When I first got it I was able to read data from it fairly easily. As I was working on my project I accidentally connected my 5V rail to my gnd (poor eyes) and fried my LCD I was using to monitor the GPS strings. I connected a second LCD and was unable to get any data from the GPS. I assumed I probably damaged it so I purchased another one. I am still having the same problem though. The LED on the module is solid which indicates (per the documentation) that the GPS is locked and receiving data. Yet none of the code I have tried (kickstart, tinygps examples, simple serial reads) will show me valid strings. I have checked every pin on the propeller with an o'scope and as far as I can tell my serial data output is fine, my rails are fine; everything seems to work. I have tried using a serial terminal, two different LCDs, blinking an LED upon receiving a valid string. No joy.

Can anyone suggest something I have not tried? I am not terribly knowledgeable about GPS chipsets but is it possible that after the initial cold start when it worked, I could reset the module and force another cold start? Would this make a difference? I have tried with direct view of the sky outdoors, by a window, in a room, stationary, and moving. I have tried with 3.3V and 5V using batteries, AC adapters, and USB power. Oh, and I have tried with two different Arduinos (Mega2560 and Uno) as well as my Prop.

Thanks for any assistance.

Cheers,
-Al

Nick Ernst

Hello Al,
I have sent you a private message. I'll get you back up and running as quickly as possible!

-Nick

GordonMcComb

In addition to Nick's help, I thought I'd add: Does the LED on the GPS ever light up? If blinking it's acquiring satellites; if always on it has satellite lock. Either would show the module is at least functioning. If always off, I imagine the module got toasted.

-- Gordon

al.arduengo

GordonMcComb wrote: »

In addition to Nick's help, I thought I'd add: Does the LED on the GPS ever light up? If blinking it's acquiring satellites; if always on it has satellite lock. Either would show the module is at least functioning. If always off, I imagine the module got toasted.

-- Gordon

Thanks for the response. To answer your question, yes the LED does blink then go solid. I spent some more sleep time playing with it and have found that my Arduino Uno will work but neither my Arduino Mega nor my Propeller will work with it. I have verified that both modules lock and transmit data.

Now, I am wondering if I actually damaged my two boards or is it possibly something else? As I said I have verified that all pins on the Mega and the Propeller wiggle with serial data but I will have to study up on serial data format to determine if the micros are actually transmitting data correctly or are they not receiving data correctly from the module. Any suggestions on how best to do it would be appreciated.

Thanks so much for the assistance!
-Al