Using a Transceiver with GPIO

Question

I'm still trying to get my head round exactly what can and can't be achieved with these devices, but I'd like to try the following:

I've found a guide for interfacing with home automation equipment here. It demonstrates using a particular transceiver. I'd like to know whether it's possible to use a different transceiver, in particular this one (because of the frequency range). I'm assuming that it's just a case of mapping the pins to the relevant GPIO sections, and then tweaking the code. Is there anything glaringly obvious that I'm missing?

I have a degree in Computer Science and spend a lot of time programming in .NET so the programming side of things doesn't bother me, but the hardware side is completely new!

Edit: I've a feeling that most of the information that I need will be in this PDF. It shows the pin layout and also goes in to a lot of details about how to actually use the chip.

I'd also like to mention that if I get this working I plan on writing up my experience with it in a guide in a similar fashion to the one that inspired me.

Answer 1

The answer is yes. Yes you can use any transceiver you want. Bitbang (I bet they did not teach you that in .NET classes) but better use the hardware UART!

---

I would strongly suggest you use a complete PCB and not just a IC on its own! Just because the pin says connect RX here, TX there and power there- Does not mean it will just work! You need the antenna also; All various sizes for each frequency. It has to be near perfect or you will get poor range, performance. Just find a complete PCB some on ebay, sparkfun, digikey, cool components, farnell, etc etc

• You (and me- cause I am MCPD) and other are pretty lucky to have MONO already ported and 80% working for the Raspberry - Otherwise you would have to learn Perl, C, or the ghastly unstructured PHP language/mark-up/something. But it has its limitations.

I have already written code on VS2012 and deployed it to the Raspberry Pi. Got some LED's turning on and off. Yay! But for months been trying to do some clever thing and just cannot get it working. Bummer.

• But as .NET developer that also never had hardware experience and dropped my self into the embedded world. I suggest you go and buy a Netduino if you want to do fancy embedded things, it is supprted by Microsoft, free dev env and a micro framework.

• Also if you want to with C I suggest you start with the Arduino as this will eeeaaasee you into the C embedded environment. C is also basis of all Linux so that will help if you want to stick with Arduino. Arduino also has an excellent community!

Answer 2

I think you prepared it all pretty good.

You even got an advantage over the way things are done in the original article (your inspiration) because the MRF49XA is a transceiver IC. The article uses a transmitter and a separate receiver module. Second the MRF49XA communicates over SPI, while the original article was a little vague on that part (or I missed it).

But you also have a disadvantage, those modules that are used in the article are ready to use/connect modules, bought on (I guess) ebay for a very low price. You on the other hand will only have a bare IC that needs all the supporting components added to make it a working electronic module.

If that is not a problem (soldering, designing a PCB, etc) you are good to go (I did see an application note in the datasheet so that could be your guide to get the IC working).

I took the liberty to search around a little on this IC, and found a link that might interest you, it is a generic article about someone that used this IC in a similar way as you are planning to do, but connecting is to an AVR micro controller. This article might include some useful tips and information, but the reason that I bring it up is because at the end of the article, the person says that he uploaded the PCB layout to BatchPCB, this means that you can order a bare PCB there, add the components and you have a module ready to go!! Of course the PCB is based on his schematic, which suspiciously looks similar to the application note of the MicroChip Datasheet... This might save a lot of time..

Another option might be to search a little on ebay for similar device modules, but you need to check all the specifications of these devices with your requirements obviously.