On Tuesday 11 September 2007 08:48:49 am Leonardo wrote: > Steve McKown ha scritto: > > On Tuesday 11 September 2007 08:25:14 am Leonardo wrote: > >> Hy guy, > >> I need to help. I want to capture the clock of my telosb. I know that i > >> have to use MSP430 but how? > >> how can I get the clock with MSP430? > > > > Two questions: which clock do you want to get, and how do you want to get > > it? For the former, the msp430 maintains a number of clocks, for example, > > MCLK, SMCLK, ACLK. For the latter, are you wanting to expose the clock > > to a digital output pin for use by a bit of add-on hardware, or do you > > want to expose it to a software component to trigger some action? > > > > Steve > > i need to get the clock because i have to sincronized my wireless > network. i have to get the clock and set the clock on my telosb. i > didn't know that there are many clock in telosb, but I need to only one. > Thanks for help me
You probably want to look at the msp430's Timer B, which is wired in TinyOS to the 32KHz crystal. This clock runs even in sleep mode, which is probably what you need to deal with timed radio events. The standard TinyOS Timer<TMilli> is a software timer attached to Timer B. There may be a 32KHz resolution Timer<xxx>; I don't recall off the top of my head. So I presume that you'll pass around some kind of timebase or offset in radio packets between nodes, when the nodes can then use to determine which next to transmit or receive. You probably can't manage more than a gross coordination without digging into the radio's software stack. If you can, try to use the LPL (low power wireless) mode of the cc2420 radio stack. It's already there and works pretty well. If you need something else, check the TEPs; there's one that covers the software layers in the new stack, and you could create your own layer to implement a new timing policy if that's what you need. Cheers, Steve _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
