Cygwin and GCC for Dummies

Wireless & IoT
1

I’m interested in the Jennic platform for its capabilities–32-bit processor and wireless transceiver in a nice module, but it looks like I’ve got some learning to do if I’m going to port my PIC design over to it.

I’ve downloaded and built the sample apps for the Jennic module (node and coordinator), but it involves the Cygwin environment and GCC compiler. Can someone provide a primer on these things? Specifically, I’m curious about:

  1. If GCC is just a compiler, why is Cygwin necessary? And does that mean that the chip is running a Unix OS?

  2. There doesn’t appear to be a ‘main’ function in their C-code (which the CodeBlocks IDE choked on); how is that possible in C programming?

  3. How does one make a Make file?

I know these are fundamental questions, but thought if I’m wondering them maybe someone else is, too.

Thanks much,

Jeff

2

that compiler needs a bunch of Unix-like shell commands - thus the crutch for windows.

remember that the 802.15.4 chips and modules can be used WITHOUT ZigBee routing. This is what you want if you don’t need self-forming, self-healing meshing, i.e., you just need A to talk to B or C direct, no hopping. ZigBee 1.0 is still kind of beta; 1.1 is due out later in 06.

the major chip (not module) makers are

TI/Chipcon - started it all. Uses ZigBee stack from F8 Wireless

Freescale - catching up

Ember - specialized chips and modules,e.g., for automated meter reading

Silicon Labs (the 8051 people)

Atmel - just entering the radio chip market; not stable yet with the stack

ZMD see below

Just FYI, the module endors I know of are…

MaxStream/Digi, XBee, XbeePro: low cost, simple, thru-hole mount

Helicomm/Silicon Labs similar to MaxStream, more cost, SMD mount

(I have used both of these)

Jennic - unique but pretty complicated due to quasi-open-source. Not the least cost modules. Low cost dev kit. Unlike the above, you’ll likely have to dig into on-module software rather than use a simple API, e.g. the Hayes AT commands that MaxStream has, as well as a binary packet API option. Maybe it’s not that bad.

Panasonic and OKI - these are at Mouser/Digikey; low cost

Ember - OEMs only

Crossbow - OEMs only

Dust, Inc. - OEMs only

Meshnetics - little US presence (Moscow)

MoteIV - interesting, small co. UC spinoff

Eazix - October 06 avail. They’re in the Phillipines.

ZMD - 900MHz (all the above are 2.4GHz). Chip maker.

Clarity Design (San DIego) and Talon Communications (San Diego), in the US; others in the EU use ZMD.

Remember too that if you want more than about 50 ft line of sight or plan to penetrate walls/floors, or want enough signal margin to cope with blockages like a person’s body, it is prudent to choose a module with a chip with a transmitter that has more than 1 or 3 mWatt. Only a frew do. Some are 30-60mW, e.g., MaxStream XBeePro or similar from Helicomm. Costs almost twice as much though. But 1 or 2mW at 2.4GHz just can’t do that well. This is why some choose ZigBee/802.15.4 on 900MHz.

3

You forgot Aerocomm modules. They look to be roughly equivalent in price and performance to the Maxstream modules, but appear to use the TI/chipcon CC2430. The major difference I see operationally is that they’re surface mount.

Still looking for more information… no publicly available technical datasheet right now.

4

SOI_Sentinel:
You forgot Aerocomm modules. They look to be roughly equivalent in price and performance to the Maxstream modules, but appear to use the TI/chipcon CC2430. The major difference I see operationally is that they’re surface mount.

Still looking for more information… no publicly available technical datasheet right now.

yes- Aerocom’s ZigBee offering. Sorry - they’re stealthy re ZigBee. Their website says they haven’t yet been through certification, but this is simple with the TI/Chipcon base. TI/Chipcon was (is) the first to have a 2nd gen ZigBee chipset with the MAC/PHY radio and the MAC/NWK layer firmware on the same chip’s microprocessor. Aerocom is one of the few with an optional high power module - important in many/most situations.

Their non-high power seems to have way less power than most everyone else- spec sheet says -2dBm including 2dBi of antenna gain = -4dBm Pout. This is less than a 1/2 mWatt whereas most other have at least 1mW.

about half of these modules are surface mount. The Helicomm SDK has this odd (for me) arrangment of spring clips to mate with the module for testing; the module pops-into these clips and sits fairly securely. But these things aren’t socket-able. I guess the idea is that in volume $5ea they’re expendable.

5

Stevech and SOI-

You guys have offered excellent feedback and thoughts–thanks for that. I’m really questoining my tendency towards the Jennic module now that you’ve presented the different options! The thing I liked about their offering was the fact that it was a 32-bit processor AND incorporated the wireless module… So all I had to add was sensors and I/O. The downside was that I have to learn their APIs, compared to MaxStream and friends where I just treat it like a wireless Black Box and send it data that magically appears at the other ends. The downside with those solutions (I think) is that I have more pieces parts (module + processor + sensors/IO) rather than a single-module, but the good thing is that I can leverage my PIC code and continue to use a familiar platform.

I’m going to weigh the options you’ve listed; and it begs me to list my priorities to winnow the choices to what I really need.

I’m looking for: Low-cost, low parts-count, easy interface, respectable(?) power transmission capability–i.e. not tiny.

Thanks for the input and responses,

Jeff

6

MJ, you’re welcome although I’ve only given a little info so far, here’s a few more thoughts for you.

The Jennic parts have a 32 bit processor core in them. Maxstream and Aerocomm are running 8 bit cores (Freescale M09 and an enhanced 8051 core respecitvely). It’s actually possible to firmware upgrade the Maxstream and put your own code on there, but you’ll lose the software stack and have to install your own. They have a UART bootloader onboard. Looks pretty nice. The Jennic modules should be more powerful

The September issue of Circuit Cellar has a nice article on the Maxstream modules by Fred Eady.

Pricing and availability:

Maxstream is available from Digikey, 1mW is $23, 100mW is $36

Aerocomm is available (no stock right now) from Mouser, for $23 and $30 respectively. Still no good datasheets out, so it’s a less mature product.

I personally would kill for an SPI interface, but then I’d consider rolling my own.

7

I suggest that for hobby or low volume applicaitons, you are best to avoid getting into the microprocessor that hosts the MAC layer protocol. It’s a tangled web and you have to buy the full SDKs or, in the case of Jennic and a few others, you have to dive into a huge collection of open source code. (meaning caveat emptor).

Hanging a low cost micro of your own on the radio module’s serial port may add a part, but your project will be working in days rather than months. But then, you may want to do a deep dive into open source. Problem is, this is a moving target; about the time you “get it”, the code base will be superceded.

as I said earlier, be sure to check things like Aerocomm’s TX power; you don’t want a sub-milliwatt transmitter. 1mW (0dBm) is shakey enough. I’d lean towards spending more for a 50mW or so module (XBeePro is an example), unless your range is quite short. XBeePro is 60mW as I recall. 100mW is 20dBm.

8

Thanks for the thoughts, guys; I did a bit of a comparison listing all the options and I do love the easy interface (and pin-for-pin compatibility) of the separate 8-bit modules. Admittedly the main thing I don’t like is the separate piece aspect of it–I’m a minimalist and would prefer as few parts as possible, but it would come at the price of development time (and moving target). The tangled web of running an application on the same hardware as an open source MAC might be shaky, and I’m a beginner. Besides, I’ve written some efficient code that squeezes onto an 8-bit PIC 18lf4550 and only takes up 10% of the space, so the easy interface / higher-power / upgrade path of the AeroComm and XBee are attractive.

Jeff