REV. M

Page 12

September 1998

AS3502

Bit No

Symbol

Name and Description

D7-D6

-

These bits are Low during a read operation.

D5

LOOP

Loop Back Mode Enable. When set to High a loop back mode is enabled where the

output of the sigma delta converter is directly fed to the input of the 1-bit DAC and

where the output of the interpolation filter is fed to the input of the decimation filter.

D4

CLIPRX

Receive Channel Clipping. On reading this bit a High indicates an overload condition in

the receive channel.

D3

CLIPTX

Transmit Channel Clipping. On reading this bit a High indicates an overload condition in

the transmit channel.

D2

ENEP

Enable Earpiece. When set to High the earpiece driver is enabled. When set to Low the

earpiece driver is powered down.

D1

ENSPK

Enable Speaker. When set to High the loudspeaker driver is enabled. When set to Low

the loudspeaker driver is powered down. Both drivers may be activated if necessary

e.g. for call progress monitoring.

D0

NOV

No Voice. When set to High the voice signal in the receive channel is muted.

3) ANALOGUE GAIN REGISTER

This register contains control bits for enabling on of the two microphone inputs and data for setting the analogue

microphone amplifier and earpiece amplifier gains.

AG

D7

D6

D5

D4

D3

D2

D1

D0

Name

0

ENM2

ENM1

AGX2

AGX1

AGX0

AGR1

AGR2

Default

0

0

0

0

1

0

0

0

Bit No

Symbol

Name and Description

D6

ENM2

Enable Microphone 2 Input. When set to High the microphone amplifier is connected to

the MIC2 + and MIC2 - inputs.

D5

ENM1

Enable Microphone 1 Input. When set to High the microphone amplifier is connected to

the MIC1+ and MIC1- inputs.

D4-D2

AGX2

-

AGX0

Analogue Transmit Gain Setting (AGX).

AGX2

AGX1

AGX0

Microphone Gain

0

0

0

+15.5 dB

0

0

1

+21.5 dB

0

1

0

+27.5 dB Default Value

0

1

1

+33.5 dB

1

0

0

+39.5 dB

1

0

1

+45.5 dB

D1- D0

AGR1

-

AGR0

Analogue Receive Gain Setting. (AGR).

AGR1

AGR0

Earpiece Gain

0

0

-12 dB Default Value

0

1

-6 dB

1

0

0 dB

1

1

+6 dB