User manual

C H A P T E R 3 - S E R I A L I N T E R F A C E 8
Note: CTS is always enabled by default. RS-485
Interface does not support Hardware flow control.
DESIGN TIP
Can I implement a design using just Txd, Rxd and Gnd (Three-wire Interface)?
Yes. However, it is strongly recommended that your hardware monitor the CTS pin of the
radio. CTS is taken High by the radio when its interface buffer is getting full. Your
hardware should stop sending at this point to avoid a buffer overrun (and subsequent loss
of data).
You can perform a successful design without monitoring CTS. However, you need to take
into account the amount of latency the radio adds to the system, any additional latency
caused by Transmit Retries or Broadcast Attempts, how often you send data, non-delivery
network timeouts and interface data rate. Polled type networks, where the Server host
requests data from the Client host and the Client host responds, are good candidates for
avoiding the use of CTS. This is because no one transceiver can monopolize the RF link.
Asynchronous type networks, where any radio can send to another radio at any point in
time, are much more difficult to implement without the use of CTS.