Everything Arduino Questions

Hey everyone, welcome to my second forum :) . This forum will be all related to asking arduino questions. Instead of making a new forum every time I have a question, I figured I would make it simple and just do it in one forum. Since so many forums get posted every day. Anyways, that's pretty much it. Any help you guys/ gals can give me would be much appreciated. Thanks in advance :)

Starting out how would I transmit gprmc strings from gps unit over i2c to another arduino whenever parsed values change?? Or would I need to be able to request string to be sent after certain timeout?? Ie, multimaster setup. Would it also be possible to send any other data?? Such as lcd commands or any info at all to another arduino on i2c, or the only thing it can do is blink led??

Bigger Bigger Smaller Smaller Reset Reset Reply with quoteQuote Hey everyone, welcome to my second forum smiley . This forum will be all related to asking arduino questions. Instead of making a new forum every time I have a question, I figured I would make it simple and just do it in one forum. Since so many forums get posted every day. Anyways, that's pretty much it. Any help you guys/ gals can give me would be much appreciated. Thanks in advance

Sorry I have no idea what this means.

how would I transmit gprmc strings from gps unit over i2c to another arduino

You can only do this if the gps unit talks I2C, I think this is unlikely as all the ones I have seen are serial. Therefore you would have to have an arduino or other processor to convert the serial to I2C.

niababygirl: Hey everyone, welcome to my second forum :) .

Thank you. Pleased to be here.

niababygirl: Ie, multimaster setup.

Just remind me what this means.

I don’t believe that I2C is designed to be multi-master… so if you find a way to do that… let Philips/NXP know.

Talking about Philips, try this: http://ics.nxp.com/products/sc18/datasheet/sc18im700.pdf

If that seems too hard… why not keep it RS232 and just let the arduino read the strings in native format… 4800 baud, NMEA sentences using “SoftSerial” library if you need more Serial I/O pins.

I don't believe that I2C is designed to be multi-master.

Yes it is. I have worked on several multi-master systems. However there problems with noise. What happens is that before making a transmission the master listens on the line and if it sees activity it assumes it is from another master and backs off for a time. Unfortunately some times noise can be mistaken for an other master and so it continually backs off and appears to hang.

I understand that there is an arduino version of an I2C multi-master systems, but it is not a thing for beginners to go messing with just because they don't understand what they are trying to do.

I don't believe that I2C is designed to be multi-master.

Ok, I'll chalk that up to my avoidance of I2C in general.

At 4800 baud though, It still makes a lot of sense to use softserial here.

Starting out how would I transmit gprmc strings from gps unit over i2c to another arduino whenever parsed values change??

Simply parse the data you want from the GPRMC string, configure one Arduino as slave and the other as Master and send the data.

pwillard: I don't believe that I2C is designed to be multi-master...

Oh, I see. I have a multi-master demo sketch here:

http://gammon.com.au/i2c

You will have some problems with collisions. I don't know about that being worse with Multi Master, Mike (hmmm, MMM), because the hardware doesn't know it is multi-master necessarily. So noise would be a problem anyway.

I'm curious though. What GPS does I2C? Can you give a model number?

I'm curious though. What GPS does I2C? Can you give a model number?

I believe U-blox has a few models that support I2C but they call it DDC protocol which is supposed to be I2C compliant.