
64
4173E–USB–09/07
AT89C5132
Figure 14-6. Voice or Sound Mode Audio Flows
Note:
1. An under-run occurrence signifies that the C51 core did not respond to the previous sample request interrupt. It may never
occur for a correct voice/sound generation. It is the user’s responsibility to mask it or not.
14.7
Registers
Table 51. AUDCON0 Register
AUDCON0 (S:9Ah) – Audio Interface Control Register 0
Reset Value = 0000 1000b
Table 52. AUDCON1 Register
AUDCON1 (S:9Bh) – Audio Interface Control Register 1
Load 8 Samples in the
Audio Buffer
Voice/Song Mode
Configuration
Configure Interface
HLR = X
DSIZ = X
POL = X
JUST4:0 = XXXXXb
DUP1:0 = XX
Program Audio Clock
Enable DAC System
Clock
AUDEN = 1
Wait for DAC
Enable Time
Enable Interrupt
Set MSREQ & MUDRN1
EAUD = 1
Audio Interrupt
Service Routine
Under-run Condition1
Load 4 Samples in the
Audio Buffer
Sample Request?
SREQ = 1?
7
6
5
4
3
2
1
0
JUST4
JUST3
JUST2
JUST1
JUST0
POL
DSIZ
HLR
Bit Number
Bit
Mnemonic
Description
7-3
JUST4:0
Audio Stream Justification Bits
2
POL
DSEL Signal Output Polarity
Set to output the left channel on high level of DSEL output (PCM mode).
Clear to output the left channel on the low level of DSEL output (I2S mode).
1
DSIZ
Audio Data Size
Set to select 32-bit data output format.
Clear to select 16-bit data output format.
0
HLR
High/Low Rate Bit
Set by software when the PLL clock frequency is 384Fs.
Clear by software when the PLL clock frequency is 256Fs.
7
6
5
4
3
2
1
0
–
MSREQ
MUDRN
-
DUP1
DUP0
AUDEN