SparkFun Forums

[ryan]

hi all
how can i make Lassen iQ to output RMC senctences instead of GGA
thnx...

[Caffeine]

hi all
how can i make Lassen iQ to output RMC senctences instead of GGA
thnx...

Use the GPS breakout boards, connect it to the PC and send the appropriate messages to it using the software supplied by trimble (IQ Monitor)

[ryan]

which port should i connect it to ?
Port 1 or Port 2 ! and what are those appropriate messages.
thnx...

[jandirks]

I take it you didn't read the datasheet?

Have a look at it first, then you will find your answers. Appendix A for RMC and chapter 2 (hardware integration)

[Craig]

Hello, Newbie here.

I've just ordered the GPS logger complete kit, I did this because I haven't done any low-level programming before and it's been ages since I did any soldering. I figured it would be easier to get the whole thing premade but now I am discovering things that I'd really like to change, like getting out the RMC sentence and the frequency of the recordings. Since I'm using this for hiking I need a long battery life and logging can be as slow as every few minutes.

I have a friend who has done some embedded programming but before I get him involved I want to have everything ready. I see there is something called iQ_CHAT that can communicate with the GPS module in the logger kit. Since I have ordered the whole thing, will I be able to access the GPS Module (via the serial port boot loader http://www.sparkfun.com/commerce/produc ... cts_id=714 I presume), or is it now soldered into place where I can't get direct access to it? Where do I get the iQ_CHAT program from? and has anyone previously configured one of these to output only the RMC sentence and then record the output at a much slower rate?

[jandirks]

I can only answer your question about the iq_chat software, it is available from the product page of the LassenIQ, here is a direct link to the software: http://www.sparkfun.com/datasheets/GPS/iQ_Chat.zip.

[Craig]

whoa, I was sure I looked at that page, some how I missed it. Thanks for making me look again, that'll definitely come in handy. So now I just to find out if I can reprogram the Lassen IQ as part of the complete datalogger kit, and whether I need that LPC Boot Serial Port Loader to do it.

[Caffeine]

whoa, I was sure I looked at that page, some how I missed it. Thanks for making me look again, that'll definitely come in handy. So now I just to find out if I can reprogram the Lassen IQ as part of the complete datalogger kit, and whether I need that LPC Boot Serial Port Loader to do it.

The logger isn't the bit that needs to be reprogrammed. The lassen IQ itself does, and to do that you need to connect to serial port 1 on the GPS unit, (the TSIP port) and use IQChat to reconfigure the GPS to output whatever sentences you want.

Battery life won't be affected by how often the GPS sends out a packet. The GPS consumes 27mA whenever it's powered up and the rest of the logger takes up 80mA, which is mostly the SD card.

If you want to save battery life, you'll need to reprogram the logger to only power up the GPD periodically, and to manage the power on the SD card better (they take 5 to 15mA in low power mode)

[Craig]

I got as far as discovering that packet 0x7A will help me tell the Lassen which NMEA sentences I want it to produce and how often. I'm still waiting for the kit to arrive so I've yet to test anything out but I was working on the theory that if the data logger only records the stuff that comes out of the GPS module, then getting the module to send packets every 255 seconds rather than every second would mean less writing and thus less power. Of course it could be that it is the 'listening' for packets that takes up the power.

I have the source code for the logger's firmware that is listed on the product page, but I haven't got a clue what to do with it. Even if I knew where to edit it I wouldn't know how to compile and load it. All my programming is based in IDEs and results in an application I can see, firmware is a whole new thing. So if you have any advice/tutorials I'm all ears.

Can you confirm that the LPC serial port boot loader is able to work on the GPS module, not just the data logger?

cheers.

[Caffeine]

I got as far as discovering that packet 0x7A will help me tell the Lassen which NMEA sentences I want it to produce and how often. I'm still waiting for the kit to arrive so I've yet to test anything out but I was working on the theory that if the data logger only records the stuff that comes out of the GPS module, then getting the module to send packets every 255 seconds rather than every second would mean less writing and thus less power. Of course it could be that it is the 'listening' for packets that takes up the power.

I have the source code for the logger's firmware that is listed on the product page, but I haven't got a clue what to do with it. Even if I knew where to edit it I wouldn't know how to compile and load it. All my programming is based in IDEs and results in an application I can see, firmware is a whole new thing. So if you have any advice/tutorials I'm all ears.

Can you confirm that the LPC serial port boot loader is able to work on the GPS module, not just the data logger?

cheers.

I don't think the LPS loader will work on the GPS.

And also, wriing ess often will not save you battery power, the SD card is initialised by the logger board, and from then on uses ~80mA, whether you're writing to it or not. You'll need to rewrite the logger firmware to initialise the SD card only when you're writing to it, and that's not a trivial task...

[Craig]

That's a pity about not reaching the GPS module. I've reposted the question into another thread to see if anoyone has definite experience. Since I don't need the logger for long term trips until next year I might just wait to see if anyone else writes appropriate firmware for slower logging and better battery life. I hope if someone does make those changes they'll share them and their instructions.