Smart Com Radio Transceiver IC
RF600T
the buffer will be transmitted to the host. When the RTS line is taken high then data flow will be inhibited
and until the buffer is empty the device will not be able to perform any other operations.
Packet Size and Timing
The following information is provided to aid in timing calculations for the RF data transmission.
Element
Run-In / Pre-amble
Sync Pattern
Start Bit
Command Byte
Source Address
Destination Address
Data Bytes
Checksum
Size (bits)
76
4
1
8
32
32
xxx
8
Modes Present
Both
Both
Both
Both
Addressed only
Addressed only
Both
Both
Addressed mode packet overhead:
PO
a
= 76+4+1+8+32+32+8 = 161 bits
Addressed Transmission time, presuming 200uS element time, no idle period:
TT
a
= 200uS x (PO
a
+ No. Data Bits)
Please note this timing is for RF transmission only the RS232 communications timing is not included.
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.
DS601-4
25 JUN 2004
th
©2004 Reg. No. 227 4001, ENGLAND
Page 6
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