DS600-10 March ‘06

©2004 Reg. No. 227 4001, ENGLAND

Page 20

RF / IR Encoder / Decoder Chipset

RF Evaluation Boards,

RF600E

RF600D

Module

Reference

Links to make

R5.

(M2)

LK3, 4

RRFQ1.

(M3)

LK5, 6

HRR3

(M4)

LK7, 8

RF600 Decoder Circuit.

The RF600 decoder stage of the RFEVAL2 board is implemented using the RF600D chip. This device

offers a complete ‘system on a chip’ solution to radio data reception, Keeloq decoding and non volatile

memory handling. Examination of the circuit diagram and layout reveals that U1, the RF600D device, is an

18 pin part which can be either in a DIL or a surface mount package. The associated 4 MHz resonator (X1)

provides a timing reference for the RF600D. A 93C76 EEPROM memory provides 512x16 bits of non

volatile memory which is used to store data on the encoders (up to 50) which have been ‘learned’ by the

system. Also in this circuit area can be seen a ‘learn’ switch (SW1) and an LED (LED1) and these parts are

used to control and indicate progress of both encoder learning and also data erasure. Option link fields are

provided for a number of functions:

OPT1 allows the selection of radio data or IR data.

OPT2 allows the selection of latch or momentary mode for the data outputs.

OPT3 allows the selection of input data sync pulse ‘mark’.

Note that where space is tight, a serial only version of the decoder - the RF600E is available in an 8 pin

DIL/SO package. This device does not decode the KeeLoq stream but after verifying that the data packet is

a true Manchester encoded packet, extracts the encoder serial number and button status and outputs this

as serial data. In applications where the high security level of KeeLoq encoding is not required, this device

provides a simple solution to the problem of reading and verifying data from the noisy data output of a radio

module.

Radio or IR data selection.

The RF600D chip can decode signals from either the radio modules or the IR receiver device and option

field OPT1 allows the selection of the desired input.

Input

Make OPT1 link

Radio data

RF

IR data

IR

Output function.

The RF600D chip has 4 data outputs and these can operate as either all latched or all momentary.

Output mode

Make OPT2 link

Latch all

LATCH

Momentary all

MOM