DS601-4

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©2004 Reg. No. 227 4001, ENGLAND

Page 4

Smart Com Radio Transceiver IC

RF600T

Dual Pin Functions

As shown in the pin function list above, a number of output pins have dual usage. During power up

they are briefly configured as inputs to allow the selection of system options as shown below. Note

that any load connected to these pins must not bias the RF600T pin such that the option setting

network is significantly disturbed.

In order to configure these pins it is recommended that they are connected as shown.

1. Tie the relevant pin to Vcc or GND via

a 100K resistor. This is useful if the

option is permanently unselected.

2. Tie to Vcc or GND via a 100K resistor

and also add a jumper link and 2.2K

resistor to the other rail. This allows the

user to select the function of the pin by

insertion/removal of the link.

Pin

Number

Name

Type

Description

3

LOOP

CTS

In

Out

Function during power up:

Sets RF600T into ‘Loop back’ Mode (see below)

Disabled if connected to Vcc as shown above.

Enabled if connected to GND as shown above.

Function after power on:

Clear To Send control line to host (when low).

9

HBAUD

TxR

In

Out

Function during power up:

Host Baud rate Select.

9600baud if connected to Vcc as shown above.

19200baud if connected to GND as shown above.

Function after power on:

Transmit data to radio module..

10

RFBAUD

TXEN

In

Out

Function during power up:

Controls the baud rate for the RF link.

400uS if connected to Vcc as shown above.

200uS if connected to GND as shown above.

Function after power on:

Transmit enable (low) to radio module.

Learn pin (addressed mode only)

The learn pin is used both to sense the learn/erase switch and also to drive the indicator LED and should

be connected as shown in the application circuit. The switch, which should be of the normally open type,

should be connected from the learn pin to ground. The LED and its series current limiting resistor should

RF600T

Pin

100K

Ω

Vcc

2.2K

Ω

RF600T

Pin

100K

Ω

Vcc or GND