Datasheet

79
4341H–MP3–10/07
AT8xC51SND2C/MP3B
Reset Value = 1011 0010b
Table 14-5. AUDSTA Register
AUDSTA (S:9Ch Read Only) – Audio Interface Status Register
Reset Value = 1100 0000b
6 DRQEN
MP3 Decoded Data Request Enable Bit
Set to enable data request to the MP3 decoder and to start playing song.
Clear to disable data request to the MP3 decoder.
5 MSREQ
Audio Sample Request Flag Mask Bit
Set to prevent the SREQ flag from generating an audio interrupt.
Clear to allow the SREQ flag to generate an audio interrupt.
4 MUDRN
Audio Sample Under-run Flag Mask Bit
Set to prevent the UDRN flag from generating an audio interrupt.
Clear to allow the UDRN flag to generate an audio interrupt.
3 -
Reserved
The value read from this bit is always 0. Do not set this bit.
2 - 1 DUP1:0
Audio Duplication Factor
Refer to Table 14-2 for bits description.
0 AUDEN
Audio Interface Enable Bit
Set to enable the audio interface.
Clear to disable the audio interface.
7 6 5 4 3 2 1 0
SREQ UDRN AUBUSY - - - - -
Bit Number
Bit
Mnemonic Description
7 SREQ
Audio Sample Request Flag
Set in C51 audio source mode when the audio interface request samples (buffer half
empty). This bit generates an interrupt if not masked and if enabled in IEN0.
Cleared by hardware when samples are loaded in AUDDAT.
6 UDRN
Audio Sample Under-run Flag
Set in C51 audio source mode when the audio interface runs out of samples (buffer
empty). This bit generates an interrupt if not masked and if enabled in IEN0.
Cleared by hardware when samples are loaded in AUDDAT.
5 AUBUSY
Audio Interface Busy Bit
Set in C51 audio source mode when the audio interface can not accept more sample
(buffer full).
Cleared by hardware when buffer is no more full.
4 - 0 -
Reserved
The value read from these bits is always 0. Do not set these bits.
Bit Number
Bit
Mnemonic Description