AirPrime Technical Specification and User-manual-3113303

4119272 Rev 2.0 August 16, 2016 31
Product Technical Specification Detailed Interface Specifications
3.14. PCM
The Digital Audio (PCM) Interface allows connectivity with standard audio peripherals. It can be used,
for example, to connect an external audio codec.
The programmability of this interface allows addressing a large range of audio peripherals.
The signals used by the Digital Audio Interface are as follows:
 PCM_SYNC: The frame synchronization signal delivers an 8 kHz frequency pulse that
synchronizes the frame data in and the frame data out.
 PCM_CLK: The frame bit clock signal controls data transfer with the audio peripheral.
 PCM_OUT: The frame “data out” relies on the selected configuration mode.
 PCM_IN: The frame “data in” relies on the selected configuration mode.
The PCM interface is a high speed full duplex interface that can be used to send and receive digital
audio data to external audio ICs. The Digital Audio Interface also features the following:
 PCM master or slave
 16 bits data word length, linear mode
 MSB first
 Configurable PCM bit clock rate on 256kHz, 384kHz or 512kHz
 Long frame sync
The following table describes the pad description of the PCM interface.
Table 23. PCM Interface Pad Description
Pad Number Signal Name I/O Description
33 PCM_OUT O PCM data out
34 PCM_IN I PCM data in
35 PCM_SYNC I/O PCM sync out
36 PCM_CLK I/O PCM clock
Refer to the following table for the electrical characteristics of the digital audio interface.
Table 24. PCM Electrical Characteristics
Signal Description Minimum Typical Maximum Unit
Tsync_low +
Tsync_high
PCM-SYNC period 125 µs
Tsync_low PCM-SYNC low time 62.5 µs
Tsync_high PCM-SYNC high time 62.5 µs
TCLK-cycle PCM-CLK period (T) 1.95 2.6 3.9 µs
TIN-setup PCM-IN setup time 59.6 ns
TIN-hold PCM-IN hold time 12 ns
TOUT-delay PCM-OUT delay time 21.6 ns