Synchronous & Asynchronous Communication - CC430

Synchronous & Asynchronous Modes of Communication

Instead of processing information through the packet handler - meaning that the application receives and transmits data through the use of the RX and TX FIFOs - customers may want to receive and transmit raw data. The synchronous and asynchronous modes of communication make up the interface to the RF1A Radio Core that is independent of the packet handling features of the integrated CC1101. These modes are useful for the implementation of a proprietary communications protocol or simply to test the RF parameters of their application prior to leveraging the features of the packet handler.

Synchronous data from the RF1A module of the CC430 to the MSP430 Core or external host processor is provided via a two-wire or two-signal interface, including a clock provided by the RF core and a data line for TX or RX data. Asynchronous data has no clock line, so it is a single-wire or single-signal interface.

These (a)synchronous signals are brought out to the MSP430 Core or host processor through the use of the GDOx lines. The GDOx signals are highly-configurable digital IO lines that communicate information about the radio core according to their settings withing the respective IO Configuration, or GDOx_IOCFG registers of the radio core. In the case of (a)synchronous communication these lines can be programmed to provide the clock and/or data lines and are connected either internally to the MSP430 Timers or can be brought out externally for interfacing with another host processor.

The internal connections to the MSP430 timers are described in the CC430 datasheet under: Short Form Description > Peripherals > Timer0_A5 and Timer1_A3.

Code Examples

1. The following file shows an example of OOK / ASK modulation at 10 kbps RF data rate for both synchronous and asynchronous mode of communication. It can serve as a good starting point for (a)synchronous communication implementations since the pin-configurations and necessary RF configuration register settings have been verified as working. Other RF parameters (e.g. - raw data rate, channel filter bandwidth, frequency of operation) in the smartrf_studio configuration files should be optimized for RF performance. Synchronous mode uses GDO0 (P2.6) for TX/RX data and GDO2 (P2.7) to output the RF clock. The Asynchronous mode uses GDO0 (P2.6) for TX/RX data. Commented are also the internal timer connections for both modes if the CC430 serves as both the application and RF processor.

         (A)synchronous Communication Example.ZIP