I am really excited about this.
We have just completed work on a whole new method of interconnecting several SPLat boards into a "very local network". We call it Xwire.
Xwire is a very easy to use, extremely low cost serial peripheral bus. If you have a CC16 or MS120, you may have noticed some 2-pin connectors labeled X1 and/or X2. On the CC16 there are 2 of them (X1 and X2). On the MS120 there is one. You can connect the X1/X2 connectors on a number of boards together using simple twisted wire, and with some very easy programming get the boards exchanging data. In effect, once it is set up with a master controller and one or more slaves, the master can swap nominated bytes of RAM with each slave.
While this may sound extremely simplistic, it is amazing how much you can achieve with it. For example, with a tiny bit of program code either end, a CC16 can become a 16 I/O expander for an MS120 or another CC16. Another possibility is to make a slave CC16 responsible for some subordinate task within a system, and simply exchange commands and status data with the master.
We call it a "very local network" because it is not intended for long haul work. There are no fancy line drivers or receivers involved (though in future we could make RS485 adapters for it). On the other hand, it is to all intents and purposes free. During our lab testing last week we ran a 21m shielded cable from the lab into my office, and two boards talked happily to each other all day with zero errors (there's a built in error counter for transmission quality monitoring). We are suggesting a maximum wiring length of 5m.
Xwire is available now as free reFlash upgrades for CC16 and MS120. We will have MMi202 and SL100 versions in a few days. You can access the documentation here.
