Smart Com Radio Transceiver IC
Digital Telemetry Lines (addressed mode only)
RF600T
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. If system is idle this
information will be transmitted as part of a ‘dummy’ data packet, which contains no data. If the system is
transferring data then the telemetry information is added in the command byte of the next transmitted data
packet.
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. (The data
packet is sent according to the flow control rules)
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.
System Testing
Testing of a prototype system can best be carried out using two PC’s running HyperTerminal with the
properties set as follows. (options not listed can be left in default state)
Connect to:
direct to COM1 or COM2
Configure (port settings):
Baud rate: 9600 or 19200 depending on RF600T setting.
Data bits: 8
Parity: none
Stop bits: 1
Flow control: hardware
Settings:
Emulation: TTY
Note that addressed mode file transfers should be tested using the drop down menu option: ‘Transfer –
Send Text File’ and NOT the ‘Transfer – Send File’ option since this latter employs modem transfer
protocols such as Xmodem and Kermit which will be confused by the ‘C’ and ‘F’ responses sent back from
the RF600T.
DS601-4
25 JUN 2004
th
©2004 Reg. No. 227 4001, ENGLAND
Page 7
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