I can answer the part about "why CC1100?"
The CC1100 radio can operate around 315 MHz, 433 MHz, and 915 MHz. The lower the frequency, the farther range you'll be able to transmit, and at a lower power output level (less energy). At 315 MHz, for example, we're able to transmit using a CC1100 radio for about 700-800 feet, on the ground, with basic wire antennas. There's a few FCC restrictions on 315 MHz, but 433 MHz is the next nicest thing. The CC1100 radio operates at 500 kbps, twice as fast as the CC2420 radio and thirteen times faster than the CC1000 in raw throughput. If you decrease the rate of throughput, you can even get farther range. The CC1100 radio is 4x4 mm, significantly smaller than the CC2420 radio. This is good for laying out a board, but the lower the frequency, the larger antenna you need as well. The CC1100 radio also has other nice features: hardware wake-on-radio (low power listening), forward error correction, FSK, MSK, GFSK, OOK, etc. to name a few. The CC2420 radio has quite a few problems: 2.4 GHz doesn't transmit very far under reasonable power output levels, 2.4 GHz is saturated with DSSS signals, etc. So if you're at all concerned about throughput, range, and chip size - then the CC1100 radio is the way to go. However, if you're interested in interfacing with other 2.4 GHz 802.15.4 devices, then the CC2420 radio is the way to go. If a small antenna size is the main concern but 802.15.4 isn't, then the CC2500 radio is the right choice. As far as interfacing both radios, this is done on a per-platform basis inside of the ActiveMessageC.nc file. Typically, you use the ActiveMessageC to forward interfaces onto the default radio. Then, you access your secondary radio directly. On my platform, I select the radio to send to on a per-message basis and have some logic at the ActiveMessageC level that directs the message to the proper device. -David _____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of roberto pagliari Sent: Saturday, December 29, 2007 5:48 AM To: jiwen zhang Cc: tinyos-help Subject: Re: [Tinyos-help] about two radioes on one mote why did you use cc1100 instead of another cc2420? the modulation scheme is more robust. to answer your question, the communication between the microcontroller and the radio is based on spi (the uController is the master). If you need some code to implement the mac layer, and the packet formatting library, you might take a look at the tinyos stack. tinyos 1.x is csma, while tinyos 2.x is a mix of b-mac and x-mac. On Dec 27, 2007 6:32 PM, jiwen zhang <[EMAIL PROTECTED]> wrote: Hello all : we design a mote which has two radioes(cc2420 and cc1100) , now each one of them can send and receive data nomally , that is to say they are ok on hardware. now i want to use both of them in one application , sometimes i use one to communicate , sometimes i use the other (not synchronously , because they use the same SPI) . How to realize it ? Maybe it is a difficult question , but i think there must be a way to solve it . Is there someone having done this work ? can you give me some suggestions ? thank you very much!!! Jiwen _______________________________________________ Tinyos-help mailing list Tinyos-help@millennium.berkeley.edu https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
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