AT83SND2CMP3 datasheet(15/97 Pages) ATMEL

15 / 97 page

AT83SND2CMP3

7524B–MP3–05/06

Frame Information

The MP3 frame header contains information on the audio data contained in the frame.

These informations is made available in the MP3STA register for you information.

MPVER and MPFS1:0 bits allow decoding of the sampling frequency according to

Table 17. MPVER bit gives the MPEG version (2 or 1).

Table 17. MP3 Frame Frequency Sampling

Ancillary Data

MP3 frames also contain data bits called ancillary data. These data are made available

in the MP3ANC register for each frame. As shown in Figure 12, the ancillary data are

available by Bytes when MPANC flag in MP3STA register is set. MPANC flag is set

when the ancillary buffer is not empty (at least one ancillary data is available) and is

cleared only when there is no more ancillary data in the buffer. This flag can generate an

interrupt as explained in Section “Interrupt”. When set, software must read all Bytes to

empty the ancillary buffer.

Figure 12. Ancillary Data Block Diagram

MPVER

MPFS1

MPFS0

Fs (kHz)

22.05 (MPEG II)

24 (MPEG II)

16 (MPEG II)

011

Reserved

44.1 (MPEG I)

101

48 (MPEG I)

110

32 (MPEG I)

111

Reserved

Ancillary

Data To C51

MP3ANC

MPANC

MP3STA.7

7-Byte

Ancillary Buffer

AT83SND2CMP3 Datasheet(PDF) 15 Page - ATMEL Corporation