LCD Terminal AppMod, Parallax GPS rx & BS2

Meepo

I can't be the first person to try to use the Parallax LCD AppMod with the Parallax GPS...is there source code somewhere I can download? I'm just a hobbyist, and this LCD AppMod is kind of tricky for me to figure out...

sylvie369

I found the LCD Appmod difficult at first as well. I spent some serious time poring through the demo code to try to figure it out, and didn't really understand it even afterwards. However, later I realized that three of the BS2 models - the BS2p, BS2px, and BS2pe - handle these parallel LCDs directly, using the LCDCMD, LCDIN, and LCDOUT commands. A lot of that mysterious code in the demo program is for the other models, and conditional compiling to accommodate the kind of BS2 you're using. If you use a p, px, or pe Stamp, the code is a LOT simpler.

I also had a difficult time figuring out how the buttons work, but I just looked at it again yesterday, and I guess I must have learned a few things since I last looked, as that buttons code looks pretty simple now, and I had no trouble writing a program that reads them.

So what I'm saying is that if you're using the LCD Appmod (or any other parallel LCD) you might want to invest in one of the Stamps that uses the LCD commands. It's pretty simple then. As for interfacing it to the GPS module, once you've learned how to read the $GPGGA NMEA data from the GPS into variables in the Stamp, it's just a matter of sending those data to the LCD. Here's a site I found helpful when I was learning to do it:

http://home.mira.net/~gnb/gps/nmea.html

Chris Savage

Meepo,

One reason we probably don’t have any example code for the LCD AppMod is that the GPS data is really more then you could fit on such a display. If you condensed the Lat and Long down into just degrees, that would be about all you could fit on that display. I think the 4x20 is more appropriate for the amount of data available from the GPS. Take care.

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Chris Savage
Parallax Engineering

Meepo

I was thinking of just scrolling through the relevant fields, though I'm mostly just interested in position, heading & speed. I'm trying to pare down the code I've got for each of these, and it still doesn't fit in the stamp...

So no one has ever used these two together?!? That's surprising...

Unsoundcode

Hi Meepo, I dont have the GPS module so don't really know what you would be looking for but I did look at the Parallax GPSDemoV1.1.BS2 and it does fill a large portion of the EEPROM.
What is good to know is that almost 50% of the code is DEBUG instructions, if you intend to use the LCD appmod you would not need need those instructions and you could use the space they provide for the LCD code. Variable space is also practically used up so it would probably be neccessary to re use some of the variables if possible.

You might start by designing a program with a subroutine that will print the contents of an array to the LCD screen, when you feel your sub routine is working well place it into a modified version of GPSDemoV1.1.BS2· that has all the DEBUG instructions removed and try to place some of the GPS data into the newly declared array for output to the LCD.

I don't know if its possible but it looks like it might be and if you already have the components at hand its going to make a really interesting project.

If its never been done this way before be the pioneer.

Jeff T.

PS. would be interesting to see your code to date it would draw some helpful comments

ProxyProdigy

This might be a little late since I just came across this post. But, since I already have pretty much one of every product Parallax sells, I'll take a look this tonight. You guys are right, this would be a cool project. I'll post my results and code on here once I have something working. Let me know if you've done anything with this before now.