Operation Manual

eZ430-Chronos Software Projects

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3.6.2 Chronos-to-Chronos (C2C) Communication

This feature is a demonstration of what can be done using SimpliciTI (peer-to-peer) and two

eZ430-Chronos watches. This code can be also be adapted to be used for custom applications, where the

communication of two eZ430-Chronos watches is required. This mode allows one watch to wirelessly

control the other. After a successful connection, it is possible to change the menus and show the

accelerometer data from one watch in the other. The communication is bidirectional, so the control can be

done from both watches.

3.6.2.1 Detailed Description of C2C Communication

When the C2C mode starts, the system sets a new SimpliciTI address for the eZ430-Chronos watches

based on the time and accelerometer data. In SimpliciTI peer-to-peer mode, the connection occurs when

one device listens and other tries to link. In C2C mode, the devices must change between listen and link

modes to enable bidirectional control. It is important to do perform the switch randomly to ensure at least

one possible state for connection. To enable this process, , one timer interrupt is set to 100 ms. The

interrupt routine calls a function that changes the connection mode in a pseudo-random way, using the

accelerometer data.

After the connection is established, the first message synchronizes the timers from both watches. This

way it is possible to ensure low power to this system, making the watches sleep most of the time and

wake for a short period of time to send and receive data.

eZ430-Chronos Software SLAU292D–November 2009–Revised March 2011

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