User Manual

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USERS MANUAL

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Document number Revision

4/198 17-LXE 108 566 Uen PA6

2.6.1 Digital Audio

The CM52 provides digital audio capability over the system connector. The digital audio

signals enable the connection of a digital audio source. The receiver is bypassing the

analog audio processing functions performed within the module. The digital audio

interface includes the following PCM signals:

Pin CM52 Description

PCMCLK PCM Clock Output from module.

PCMSYNC PCM Frame Sync from module

PCMULD PCM Voice Input to module.

PCMDLD PCM Voice Output from module.

Table 11: CM52 Digital Audio Signals

Already defined CMOS output/input electrical characteristics apply (see Section 2.3.3).

The PCM format (for PCMULD and PCMDLD) follows a linear PCM data format with

13-bit data embedded in a 16-bit word. The data bits in PCMULD (input) and PCMDLD

(output) are aligned so that the MSB in each word occurs on the same clock edge. See

timing diagram in 2.6.1.2.

2.6.1.1 Data Format

The CM-52 module implements a 13-bit PCM with the 13-bit data embedded in a 16-bit

word as follows.

Each PCM word shall contain 16-bits D15 – D00. D15 – D03 is the 2´s-complement

value of the 13-bit PCM, with D15 as the sign bit. D15 is the MSB while D03 is the LSB.

Note that the MSB is sent in first place. Ensure that the read data from PCMDLD is right

shifted three times and sign extended before being used

13-bit linear

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

MSB LSB

x x x

Bit Contents

D15 –

D03

Two complement of the 13-bit PCM.

D02 –

D00

Bits are undefined.

2.6.1.2 Timing

Timing shall be according to the following diagram (see Figure 7: PCM Timing

Diagram). The signals in the diagram shall be interpreted according to the following

relation.