DS601-2

11

©2003 Reg. No. 227 4001, ENGLAND

Page 6

Low-Power-Radio Transceiver IC

RF600T

Radio Module Interface

The interface to the radio module(s) consists of the following signal and control lines:

TxR

Serial data output from the RF600T to the radio module.

RxR

Serial Data input to the RF600T from the radio module.

TXEN

When active low the RF Transmitter is enabled

RXEN

When active low the RF Receiver is enabled

Radio Module Communications

All data communications between the radio modules are carried out using an R. F. Solutions proprietary

data protocol with Manchester coding. This protocol includes a pre-amble and synchronisation header

followed by address and control bytes, data and a CRC check. Element timing is selectable at either 400

us or 200 us using the HBAUD option as described above.

Radio Module Control

The RXEN and TXEN control lines are used to enable or disable the receiver and transmitter modules – or

in the case of a transceiver module, to control the direction of operation. The logic of these outputs is such

that when the RF600T wishes to transmit, it will take the RXEN line high and the TXEN line low. When the

RF600T wishes to receive, it will take the RXEN line low and the TXEN line high.

Digital Telemetry Lines (addressed mode only)

In addressed mode, two input pins have their state monitored at all times and when either changes state

the new states will be transmitted and applied to the outputs at the other nodes. In addition each host data

packet contains the current status of the inputs.

Some care is required in using the logic pins as shown in the following notes.

1.

The acknowledge and retry functions are not applied to these transmissions

2.

If host data is being transmitted to the device when the logic input pins change state then

the new state will not be transmitted until the current host data packet is sent.

Loop Mode

Loop mode is provided to allow testing of the performance of a system and allows node ‘A’ to transmit a

data packet which will be looped back by node ‘B’ and received by node ‘A’. The mode settings of the

nodes are ignored in the loop mode and the transfer is carried out in broadcast mode. The mode must

only be selected when there are just two nodes in a network.

If we assume that we wish to send a host data packet from node ‘A’ to node ‘B’ and have the packet

returned such that host ‘A’ receives back its data packet then the LOOP link in node ‘A’ should be made

before that unit is powered up. This unit will now only operate in the loop mode until it is powered down,

the loop link removed and then powered up again.

Note that the learn function will not operate when the system is configured for loop mode.