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Register Map

REGISTER DEFINITIONS

ATx[7:0] – Digital Attenuation Level Setting

PCM1742

SBAS176A – DECEMBER 2000 – REVISED APRIL 2005

The mode control register map is shown in Table 3. Each register includes an index (or address) indicated by the

IDX[6:0] bits.

Table 3. Mode Control Register Map

IDX

REGIS-

B15

B14

B13

B12

B11

B10

B9

B8

B7

B6

B5

B4

B3

B2

B1

B0

(B14–B8)

TER

10h

16

0

IDX6

IDX5

IDX4

IDX3

IDX2

IDX1

IDX0

AT17

AT16

AT15

AT14

AT13

AT12

AT11

AT10

11h

17

0

IDX6

IDX5

IDX4

IDX3

IDX2

IDX1

IDX0

AT27

AT26

AT25

AT24

AT23

AT22

AT21

AT20

12h

18

0

IDX6

IDX5

IDX4

IDX3

IDX2

IDX1

IDX0

RSV(1)

OVER

RSV(1)

RSV(1)

RSV(1)

RSV(1)

MUT2

MUT1

13h

19

0

IDX6

IDX5

IDX4

IDX3

IDX2

IDX1

IDX0

RSV(1)

DMF1

DMF0

DM12

RSV(1)

RSV(1)

DAC2

DAC1

14h

20

0

IDX6

IDX5

IDX4

IDX3

IDX2

IDX1

IDX0

RSV(1)

RSV(1)

FLT

RSV(1)

RSV(1)

FMT2

FMT1

FMT0

15h

21

0

IDX6

IDX5

IDX4

IDX3

IDX2

IDX1

IDX0

RSV(1)

RSV(1)

RSV(1)

RSV(1)

RSV(1)

RSV(1)

RSV(1)

RSV(1)

16h

22

0

IDX6

IDX5

IDX4

IDX3

IDX2

IDX1

IDX0

RSV(1)

RSV(1)

RSV(1)

RSV(1)

RSV(1)

AZRO

ZREV

DREV

(1)

RSV: Reserved for test operation. It should be set to 0 during normal operation.

B15

B14

B13

B12

B11

B10

B9

B8

B7

B6

B5

B4

B3

B2

B1

B0

REGISTER 16

0

IDX6

IDX5

IDX4

IDX3

IDX2

IDX1

IDX0

AT17

AT16

AT15

AT14

AT13

AT12

AT11

AT10

REGISTER 17

0

IDX6

IDX5

IDX4

IDX3

IDX2

IDX1

IDX0

AT27

AT26

AT25

AT24

AT23

AT22

AT21

AT20

where x = 1 or 2, corresponding to the DAC output VOUTL (x = 1) and VOUTR (x = 2).

Default value: 1111 1111b

Each DAC channel (VOUTL and VOUTR) includes a digital attenuator function. The attenuation level can be set

from 0 dB to –63 dB, in 0.5-dB steps. Changes in attenuation levels are made by incrementing or decrementing,

by one step (0.5 dB), for every 8/fS time interval until the programmed attenuator setting is reached. Alternatively,

the attenuation level can be set to infinite attenuation, or mute. The attenuation data for each channel can be set

individually.

The attenuation level is calculated using the following formula:

Attenuation level (dB) = 0.5 (ATx[7:0]DEC – 255)

where: ATx[7:0]DEC = 0 through 255

for: ATx[7:0]DEC = 0 through 128, the attenuator is set to infinite attenuation.

The following table shows attenuator levels for various settings.

ATx[7:0]

DECIMAL VALUE

ATTENUATOR LEVEL SETTING

1111 1111b

255

0 dB, no attenuation (default)

1111 1110b

254

–0.5 dB

1111 1101b

253

–1 dB

:

:

:

1000 0011b

131

–62 dB

1000 0010b

130

–62.5 dB

1000 0001b

129

–63 dB

1000 0000b

128

Mute

:

:

:

0000 0000b

0

Mute

17