CMX813 Просмотр технического описания (PDF) - CML Microsystems Plc

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CMX813

Multi-Standard Analogue Paging Decoder

CML Microsystems Plc 

Multi-Standard Analogue Paging Decoder

1.6 Application Notes

CMX813

1.6.1 General

The device should be reset first by the command GENERAL RESET $01.

The decoder should then be set up according to the desired characteristics. This entails setting the

DECODER BANDWIDTH and select the ROM PAGE in the CONTROL Register $30, also selecting tones in

the chosen ROM PAGE by TONE ADDRESS Register $31 (programming the centre frequencies of the

desired tones).

Up to 8 tones can be programmed either from ROM PAGE 1 or ROM PAGE 2. The RAM memory location 1

is loaded first then incrementally loaded to location 8. Alternatively, a tone group can be selected from

ROM PAGE 3.

The decoder is enabled by the CONTROL Register $30.

During operation when the device is receiving, the tones are scanned in the sequence of their location;

once a tone is detected the remaining tones are not checked.

When the decoder detects a change in its present state an interrupt will be generated. The change that

occurred can be read from Bit 3 of the STATUS Register $3F if a tone is detected. NOTONE is indicated by

Bit 2 of the same register. The ROM PAGE of that tone can be read from Bits 1 and 0 of the same register.

The interrupt is cleared by reading the STATUS Register. The decoded tone address can be read from the

DECODED TONE ADDRESS Register $38

1.6.2 Tone Tables

The tables on the following pages list the commonly used paging tones and the corresponding ROM

address for programming the TONE ADDRESS Register $31.

© 2000 Consumer Microcircuits Limited

11

D/813/33

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