CM52 Integrators’ Manual
CM52 Integrators’ Manual
WI_DEV_CM52_UGD_001-001
Page 28 of 53
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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 Wireless CPU
®
. The digital audio interface includes the
following PCM signals:
Pin
Signal
Description
17
PCMCLK
PCM Clock Output from Wireless CPU
®
.
18
PCMSYNC
PCM Frame Sync from Wireless CPU
®
19
PCMULD
PCM Voice Input to Wireless CPU
®
.
20
PCMDLD
PCM Voice Output from Wireless CPU
®
.
Table 17: CM52 Digital Audio Signals
Already defined CMOS output/input electrical characteristics apply (see Section 1.1.1). The PCM
signals are referenced to digital ground.
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 CM52 Wireless CPU
®
implements a 13-bit linear 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
2’s complement of the 13-bit PCM.
D02 – D00
Bits are undefined.
