SAA7824 Datasheet, PDF(21/89 Page) NXP Semiconductors – CD audio decoder, digital servo and filterless DAC with integrated pre-amp and laser control (PhonIC)

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SAA7824 Datasheet, PDF (21/89 Pages) NXP Semiconductors – CD audio decoder, digital servo and filterless DAC with integrated pre-amp and laser control (PhonIC)

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Philips Semiconductors

CD audio decoder, digital servo and ï¬lterless

DAC with integrated pre-amp and laser control

Product speciï¬cation

SAA7824

7.10.1.2 Loopback external data into onboard DAC

The onboard DAC can also be set to accept serial data

inputs from an external source, e.g. an Electronic Shock

Absorption (ESA) IC. This is known as loopback mode and

is enabled by setting shadow register 7 to 0000. This

enables the serial data output pins (SCLK, WCLK, DATA

and EF) so that data can be routed from the SAA7824 to

an external ESA system (or external DAC).

The serial data from an external ESA IC can then also be

input to the onboard DAC on the SAA7824 by utilising the

serial data input interface (SCLI, SDI and WCLI).

In this mode, a wide range of data formats to the external

ESA IC can be programmed as shown in Table 7.

However, the serial input on the SAA7824 will always

expect the input data from the ESA IC to be 16-bit 1fs and

the same data format, either I2S-bus or EIAJ, as the serial

output format (set by decoder register 3).

The SAA7824 is compatible with a wide range of external

DACs. Eleven formats are supported and are given in

Table 7. Figures 14 and 15 show the Philips I2S-bus and

the EIAJ data formats respectively. When the decoder is

operated in lock-to-disc mode, the SCLK frequency is

dependent on the disc speed factor âdâ.

All formats are MSB first and 1fs is 44.1 kHz. The polarity

of the WCLK and the data can be inverted; selectable by

decoder register 7. It should be noted that EF is only a

defined output in CD-ROM and 1fs modes.

When using an external DAC (or when using the onboard

DAC in non-loopback mode), the serial data inputs to the

onboard DAC (SCLI, SDI and WCLI) should be tied to

ground.

7.10.2 EXTERNAL DAC INTERFACE

Audio data from the SAA7824 can be sent to an external

DAC, identical to the SAA732x series, in âloopbackâ mode

(i.e. shadow register 7 is set to 0000).

Table 7 DAC interface formats

1010

1011

1110

0010

0110

0000

0100

1100

0011

0111

1111

SAMPLE

FREQUENCY

4fs

2fs

NUMBER OF

BITS

16/18(1)

SCLK (MHz)

2.1168 Ã n

8.4672 Ã n

4.2336 Ã n

FORMAT

INTERPOLATION

CD-ROM

(I2S-bus)

CD-ROM (EIAJ)

Philips I2S-bus

yes

16/18 bits(1)

EIAJ 16 bits

yes

EIAJ 18 bits

yes

EIAJ 16 bits

yes

EIAJ 18 bits

yes

Philips I2S-bus

yes

18 bits

EIAJ 16 bits

yes

EIAJ 18 bits

yes

Philips I2S-bus

yes

18 bits

Note

1. In this mode the first 16 bits contain data, but if any of the fade, attenuate or de-emphasis filter functions are activated

then the first 18 bits contain data.

2003 Oct 01

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