VIII.3 - Example

BIQUADRATIC

FILTER

#3

LEVEL #3

POW ER

#3

POWER

#4

POWER

#5

LEVEL #4

LEVEL #5

COMP.

#4

COMP.

#3

COMP.

#5

D3

D4

D5

BIQUADRATIC

FILTER

#5

BIQUADRATIC

FILTER

#4

RX SIGNAL

GROUND

@00

@01

@02

@03

@13

@14

@15

@23

@33

@24

@34

@25

@35

TONEDET0

2

2

Figure 6 : Wiring Example

Hereunder is an example of programming a single

Tone detection (using Cell #3) and a complex dif-

ferential tone detection (using Cell #4 and #5).

Bit 3 of the TONEDET variable will be triggered

each time the energy of that filtered signal is higher

than Static Level number 3.

Bit 4 of the TONEDET variable will be on each time

a receive signal has an energy higher than the

Static Level number 4. Bit 5 will be on only when

the Filtered (Filter section 4 and 5) received signal

higher than the energy of the wide-band signal

number 4 ; this prevents triggering on noise.

Program Cell #3 :

TDWW

03

00

13

01

Connect Received signal to Filter and Filter to Energy.

TDWW

03

01

33

23

Connect Level to Comparator Neg Input and Energy to Pos Input.

Program Cell #4 and #5 :

TDWW

04

00

01

01

Connect Received Signal to Filter and Energy.

TDWW

04

01

34

24

Connect Level to Comparator Neg Input and Energy to Pos Input.

TDWW

05

00

15

14

Connect Filter#4 Output to Filter and Filter to Energy.

TDWW

05

01

24

25

Connect Wide-band Energy to Neg Input and Energy to Pos Input.

IX - BUFFER OPERATIONS

IX.1 - Introduction

This appendixis dedicatedto buffer operation, either the data buffersused in data exchanges or in particular

Modes (like Voice).

The first part is oriented towards a functional description of the buffer operation, while the second section

is more oriented towards the management of the buffers.

ST75C520

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