Rainbow Electronics AT89C51SND1C - Manual (Page 79)

79
AT8xC51SND1C
4109E–8051–06/03
Table 86. AUDSTA Register
AUDSTA (S:9Ch Read Only) – Audio Interface Status Register
Reset Value = 1100 0000b
Table 87. AUDDAT Register
AUDDAT (S:9Dh) – Audio Interface Data Register
Reset Value = 1111 1111b
Table 88. AUDCLK Register
AUDCLK (S:ECh) – Audio Clock Divider Register
Reset Value = 0000 0000b
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.
7 6 5 4 3 2 1 0
AUD7 AUD6 AUD5 AUD4 AUD3 AUD2 AUD1 AUD0
Bit
Number
Bit
Mnemonic Description
7 - 0 AUD7:0
Audio Data
8-bit sampling data for voice or sound playing.
7 6 5 4 3 2 1 0
- - - AUCD4 AUCD3 AUCD2 AUCD1 AUCD0
Bit
Number
Bit
Mnemonic Description
7 - 5 -
Reserved
The value read from these bits is always 0. Do not set these bits.
4 - 0 AUCD4:0
Audio Clock Divider
5-bit divider for audio clock generation.