MFC2000 datasheet(359/426 Pages) ETC

359 / 426 page

Multifunctional Peripheral Controller 2000

MFC2000

100723A

Conexant

20-1

20. Programmable Tone Generators

20.1 Introduction

The AMFPC provides three programmable clock generator outputs. Two of the generators are to be used as tone

generators and the third as a bell or ring driver.

20.2 Bell/Ringer Generator

The frequency of this bell/ringer generator is programmable, ranging from 500 Hz to 15.6 Hz. This frequency is

derived from the AMFPC’s internal 125

µs period Clock, and it is calculated based on the following formula:

OutputFrequency

BellPeriod

×+ ×

125

µ ()

, where BellPeriod is ranging from 0 to 31.

Each bell/ringer period is divided into 16 phases, as shown in the following figure. The phase number may be

used by the firmware to determine when to turn off bell signal.

987654

210

Hi-Z

Phase:

Bell Mode:

Ringer Mode:

Modulated b y ALTTone Generator

period

50% x period

Figure 20-1. Bell/Ringer Timing

The mode of operation for this bell/ringer generator is selected by RingerEnb bit in BellControl register.

Figure 20-2 shows the block diagram of this bell/ringer generator.

Table 20-1shows the relationship between BellPeriod value and output frequency.

MFC2000 Datasheet(PDF) 359 Page - List of Unclassifed Manufacturers