DS601-4

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©2004 Reg. No. 227 4001, ENGLAND

Page 7

Smart Com Radio Transceiver IC

RF600T

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. 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.