skyjumper:
I had a look at the web page linked above and read this entire thread. Still, its not clear to me what's on that nice looking PCB.
If you are talking about HayTag, the three chips are: RF (SPIRIT1), MCU (STM32L), Energy Harvesting IC. If you are talking about the USB stick, it uses MSP430F5503 and CC1101. It uses the 5503 in order to utilize the USB features of that chip. CC430 would be fine, too, but there would need to be a USB bridge. I prefer having more control over the USB.
Can user specific code be placed on the CC430?
Yes, although CC430 is not used on HayTag or the USB stick. OpenTag runs well on any MSP430F5 core, and CC430 is in that family. The STM32L port is underway. There is a somewhat out-of-date STM32F port, too. The STM32L port will have better ability to run Arduino [Due] or Maple environments for user code. C code or assembly projects can work on any of the platforms. Additionally, once the STM32L port is complete, it should be very easy to port that to Due HW.
I saw the board has UART, I2C and SPI. Is this for talking to the external uC?
For talking to whatever you want. All boards with OpenTag have an internal MCU that runs the stack and can run user code, too, if you want.
Will we need to write code for the CC430 and, if so, what development tools are needed for that (compiler and hardware programmer)?
You won't need anything unusual. You can find all the answers easily on the net.
Finally, is it possible to find a radio with higher transmit power to increase the range? I saw in this thread you were talking about 8dbm in comparison to the XBee pro, which claims a line of site range of about 6 miles I think? I realize the XBee uses much higher frequency, but why is the range of this only 0.62 miles? I assume the comparison is made with comparable bit rate. Is it an antenna issue or is this just not a valid comparison?
XBee Pro uses a lot of power in both TX and RX. Higher frequencies have less range by nature, so they require large amplification and thus require a ton of power. I don't know what power level achieves 10km line-of-sight range with DASH7, but it's much less. For HayTag get 1km in USA, non-line-of-sight, the test power is -2.4dBm (0.6mW). XBee pro is using 100mW. Big difference. In EU it's allowed to transmit with 10mW in 433MHz band, in China 5mW, in Australia 25mW... so USA is the lowest range, although I hear the FCC is changing unlicensed 433 to allow more power. The rumor is 2mW with some requirements for listen-before-talk (no problem for OpenTag).