Interface for connecting CC1000PP module to RS232 interface

The CC1000PP module manufactured by Chipcon is a very nice radio data transmission solution, well suited to microcontroller systems. Unfortunately the PC interface offered by Chipcon (described here) is rather complicated and makes sending of data via the radio link a difficult task, as you need to synthesize the waveforms in software. Therefore I've decided to build another one just for UART mode, using the RS232 port for both - controlling of CC1000PP and for transmitting of data. The main problem however is that CC1000PP needs four input lines, while RS232 offers only three (TD, RTS, DTR). This problem however may be solved utilizing the particular feature of the CC1000PP communication protocol: after PALE goes down (to send the register adress) and then high, we always issue 8 PCLK pulses to transmit data to/from CC1000PP.

Therefore a small automat has been designed to connect the TD line to the PCLK input temporarily, after PALE (RTS) goes down. After 8 PCLK pulses (each pulse can be generated just by sending a 0 character to RS232 interface), the TD line will be connected again to DIO input of the CC1000PP module, and will provide it with data to be sent over the radio link.

The schematic diagram of the interface is shown in the figure above. Currently only a "wired" prototype is available.

However I've just designed a PCB layout shown in the figure below.

The layout has been prepared with the free PCB program and the gzipped source form of the layout is available.

There is also a need to write the software. I've written the first "quick & dirty" solution in Python (sorry it is not ready for publication yet), so it will be portable. Then I'll write the Linux device driver. I'm not going to prepare the Windows driver. If someone else will - please fill free to do it.

I'll update this site as soon as I have any news.

Wojciech Zabolotny

Last modified: Tue Nov 23 22:09:14 CET 2004