MC13213 student project questions

[Nir]

Hi everybody!

I am a student in my last year, and doing my final project.

In this project, I need to implement ZigBee network with one co-ordinator, and several “sensors” (mesh topology) – based on MC13213.

Each sensor board will include 4 LEDs and need to sample voice (via internal ADC). Than I need to calculate the frequency and amplitude (for now, the voice is actually a tone).

I have several questions:

1.Which demo is the best for my needs? (I planed to base my software on one of the demos, at least for the start..)

2.Is it possible to update the software remotely (I saw the SMAC OTAP, but nothing regarding the zigbee)

3.If I need to sample the voice for  ~ 10msec, does it interrupt the task-scheduler?

4.Does any of you know a good reference for my needs?

Lots of thanks,

Nir

[UK_CF_FAE]

Hello Nir,

Welcome to the forum. I work for Freescale, and I hope that my comments below will be of use to you. I'll answer your questions in turn.

First, though, I strongly advocate that you learn a little about the IEEE802.15.4 library by prototyping your project with the MAC codebase. You can get this with the BeeKit download from www.freescale.com

Answers

1) I recommend the MAC codebase, and MyWirelessApp as your starting point. This will help you bring up a simple, understandable network and get you used to MAC and the interface to it from your App.

2) Absolutely not. With the MC13213, it has 60kbytes of flash. The ram is 4kbytes. The IEEE 802.15.4 MAC will occupy at least 30kbytes, and you can't run the radio, and buffer the binary file anywhere before erasing the flash. Maybe you could place it in a serial EEPROM temporarily, but this would be some advance programming, and could be a final year project in itself.

3) You want to sample voice for 10ms. Well, you don't say what sample rate you plan to use, but if we assume 10ksps at 8bit, you'll get one sample every 100us and you'll end up with 100 samples.  The ADC will be interrupt driven, and the interrupt service routine must be less than 10us long to provide sufficient bandwidth into the MAC. I doubt that this is a problem for the ADC sampling. Not sure where you will do your FFT, though.

4) A good reference - well, as I'd say to any student - part of the engineering skills that you will learn as a student is to find good sources of reference. You could try to Google for the reference book "Speech Sampling Algorithms in a Zigbee (Mesh) Network Environment for Dummies" :smileywink:

Good luck,

Mark 

[neocronos]

Hey Nir.

I'm sure there are other people that can help you better than me but since nobody has answered yet, I'll reply your topic with what I've found so far (I'm working on a ZigBee project too ).

There are some important things you must decide before jumping into tests and code:

- Hardware
- Network stuff
- ZigBee CodeBase

Seems you already chose MC13213. Is it inside a tarjet? or are you planning to build a custom one?, for what you said you may wanna check the SARD, it saves you a lot of work.

You said too that the network will have mesh kind of topology, I've heard there are some issues with mesh. Check the star configuration, it should work fine for a coordinator with several end devices. Also, you have to decide if you will implement a beaconed or not beaconed network. I would say that it depends mostly on your project data transmission over time and battery too. There is a decent explanation at the BeeKit documentation under the IEE 802.15.4 MAC section called "MyWirelessApp User's Guide", check the chapters 5 and 6. (in my project, I'm kinda stuck at this part).

To select the ZigBee CodeBase is simple (or at least it was for me). First I tried BeeStack and I noted that you needed a license after a month. So I tried MAC, I got some issues and I went down to SMAC until I solved those issues and I saw that SMAC, as the name says, is kinda simple, is a great start tho. Right now I'm working with MAC which is free and comes with MyWirelessApp demos that are well explained at the pdf I said before.

Finally, based on your specific questions (remember that I'm a student also, not an expert):

1. MyWirelessApp Demo 6 for non beaconed and Demo 7 for beaconed. There are other demos that you can check as well.

2. I think is possible but I'm not sure of where is well explained. I do know that at the SMAC documentation, there is a chapter with some info about it. Here is the link:

http://www.freescale.com/files/rf_if/doc/app_note/AN3231.pdf

3. I'm using ADC too but with a infrared distance sensor. I use a timer interrupt bean and when it interrupts I check ADC measures.

4. Well, I don't know a specific one. BeeKit ones are useful (tho, sometimes I find them a little short). There are some random sites related to ZigBee like this one:

http://www.ifn.et.tu-dresden.de/~marandin/ZigBee/ZigBeeTutorial.html

which has a well explained beaconed network math. However, the best place to look for help is right in here

Good luck!