AT8xC51SND2C
Audio Output
Interface
The AT8xC51SND2C implement an audio output interface allowing the audio bitstream
to be output in various formats. It is compatible with right and left justification PCM and
I2S formats and thanks to the on-chip PLL (see Section “Clock Controller”, page 12)
allows connection of almost all of the commercial audio DAC families available on the
market.
The audio bitstream can be from 2 different types:
•
•
The MP3 decoded bitstream coming from the MP3 decoder for playing songs.
The audio bitstream coming from the MCU for outputting voice or sounds.
Description
The C51 core interfaces to the audio interface through five special function registers:
AUDCON0 and AUDCON1, the Audio Control registers (see Table 86 and Table 87);
AUDSTA, the Audio Status register (see Table 88); AUDDAT, the Audio Data register
(see Table 89); and AUDCLK, the Audio Clock Divider register (see Table 90).
Figure 46 shows the audio interface block diagram, blocks are detailed in the following
sections.
Figure 46. Audio Interface Block Diagram
SCLK
DCLK
AUD
CLOCK
Clock Generator
0
1
DSEL
AUDEN
AUDCON1.0
HLR
AUDCON0.0
DSIZ
AUDCON0.1
POL
AUDCON0.2
Data Ready
Audio Data
From MP3
Decoder
16
16
16
Data Converter
DOUT
0
1
MP3 Buffer
Sample
Request To
MP3 Decoder
JUST4:0
AUDCON0.7:3
DRQEN
AUDCON1.6
SRC
AUDCON1.7
SREQ
AUDSTA.7
Audio Data
From C51
Audio Buffer
AUDDAT
8
UDRN
AUDSTA.6
AUBUSY
AUDSTA.5
DUP1:0
AUDCON1.2:1
73
4341D–MP3–04/05
ATMEL [ ATMEL ]
