gps logger .... which type of memeory should be used..

Guest · Posted: Sat Jun 10, 2006 1:34 am

Hi all,

I am here with a project which needs to be log gps sentence GPRMC or GPGGA every two second(gps update rate). GPS giving rs232 output and i want to make a PIC microcontroller based simple gps logger which can record these sentences in the form of raw bytes for one day. It is basically to check the Van movment whole the day.

Now i need advise that what type of memory should be used to store these raw bytes . I have tried to use I2C memories 24c256 etc. But some time it doesnt write or read the right data to and from it. May be some circuit mistake as my electroincs side is not of much higher standard.

Is there other high speed large datastorage eeprom which can easily be intface with PIC microcontrollers. then pleasee tell

regards

kender · Joined: 09 Aug 2004 Posts: 768 Location: Silicon Valley

jaime · Joined: 25 Nov 2005 Posts: 56 Location: Porto - Portugal

Hi.
I want to do the same... i'm waiting for some electronic parts to make some tests.
I think i will work with a LF PIC, maybe 18lf2550. The pic, the gps and mmc will work at same voltage, so no need to make interface between the components. We can store 512 bytes in the RAM of the pic and then record in the mmc. Maybe its possible to use usb of the pic to send data to a PC.
Is that possible??

The dificult is to buy LF PIC in europe and the MMC socket. If someone know where can i find it...

thanks

rberek · Joined: 10 Jan 2005 Posts: 207 Location: Ottawa, Canada

Or you could use an M25P32 from ST Micro. A 32 Mbit SPI FLASH memory with 256 byte pages.

It requires far less board real estate than an MMC card.

deltatech · Joined: 22 Apr 2006 Posts: 87

Farnell In One and RS commponents both sell MMC and SD Sockets

Douglas Kennedy · Joined: 07 Sep 2003 Posts: 755 Location: Florida

If you have an old floppy cable with the female card edge connector it has the same pin spacing as an MMC card. You could cut it down and wire it so it doesn't matter as to which side of the MMC is inserted...rightside up or right side down.

arunb · Joined: 08 Sep 2003 Posts: 492 Location: India

Hi,

Just what to know isn't there any high capacity memory in PDIP packages ??

thanks
arunb

libor · Joined: 14 Dec 2004 Posts: 288 Location: Hungary

For testing you can use prototyping adapters like these here: epboard. You can make your own also.
(I also used to be afraid of the SMD parts, you have to make that move anyway from the DIP-world to the SMD era, it is not that much of pain as it seems)

arunb · Joined: 08 Sep 2003 Posts: 492 Location: India

Hi,

Thanks for the reply..

What tools would I require for soldering these components ??

thanks
arunb

kender · Joined: 09 Aug 2004 Posts: 768 Location: Silicon Valley

jaime · Joined: 25 Nov 2005 Posts: 56 Location: Porto - Portugal

Hello

Farnell isnt to cheap but its the better way for me to buy a mmc socket. But they dont have 18lf4550.

For testint i didnt find the old floppy disk connector, but i find one motherboard with a pci sockect and i pick up this socket and use it in a board.

stevenm86 · Joined: 11 Jun 2006 Posts: 11

Why log it every 2 seconds? And why log the whole message?

Write an NMEA parser (i am making one now) to pull out the lat/lon/ground speed. It works if you store it as 32-bit fractionals converterd to decimal degrees (floats arent percise enough). Then you can decode/store the data every few feet instead of every few seconds. Save some space that way.

jaime · Joined: 25 Nov 2005 Posts: 56 Location: Porto - Portugal

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

http://www.ccsinfo.com/forum/viewtopic.php?t=4402&highlight=gga

stevenm86 · Joined: 11 Jun 2006 Posts: 11

Woops, posted the code in the forum on the link above instead of this one. Look at the last post there...