AT89C51SND1C-7HTUL Atmel, AT89C51SND1C-7HTUL Datasheet - Page 76

• Manufacturer Part Number: AT89C51SND1C-7HTUL
• Description: IC MCU 64KB FLASH MEM 81-CBGA
• Manufacturer: Atmel
• Series: 89Cr

Specifications of AT89C51SND1C-7HTUL

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, IDE/ATAPI, MMC, SPI, UART/USART, USB
• Peripherals: Audio, I²S, MP3, PCM, POR, WDT
• Number Of I /o: 44
• Program Memory Size: 64KB (64K x 8)
• Program Memory Type: FLASH
• Ram Size: 2.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.3 V
• Data Converters: A/D 2x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 81-CBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

Figure 14-4. Audio Output Format
14.4
76
Audio Buffer
AT8xC51SND1C
DOUT
DOUT
DOUT
DOUT
DOUT
DCLK
DCLK
DCLK
DCLK
DCLK
DSEL
DSEL
DSEL
DSEL
DSEL
MSB
LSB
1
1
1
1
1
The data converter receives its audio stream from 2 sources selected by the SRC bit in
AUDCON1 register. When cleared, the audio stream comes from the MP3 decoder (see
Section “MP3 Decoder”, page 64) for song playing. When set, the audio stream is coming from
the C51 core for voice or sound playing.
As soon as first audio data is input to the data converter, it enables the clock generator for gen-
erating the bit and word clocks.
In voice or sound playing mode, the audio stream comes from the C51 core through an audio
buffer. The data is in 8-bit format and is sampled at 8 kHz. The audio buffer adapts the sample
format and rate. The sample format is extended to 16 bits by filling the LSB to 00h. Rate is
adapted to the DAC rate by duplicating the data using DUP1:0 bits in AUDCON1 register
according to Table 84.
The audio buffer interfaces to the C51 core through three flags: the sample request flag (SREQ
in AUDSTA register), the under-run flag (UNDR in AUDSTA register) and the busy flag
(AUBUSY in AUDSTA register). SREQ and UNDR can generate an interrupt request as
explained in Section "Interrupt Request", page 77. The buffer size is 8 Bytes large. SREQ is set
when the samples number switches from 4 to 3 and reset when the samples number switches
from 4 to 5; UNDR is set when the buffer becomes empty signaling that the audio interface ran
out of samples; and AUBUSY is set when the buffer is full.
MSB
MSB
B14
2
2
2
B14
B14
MSB B16
3
3
3
Left Channel
Left Channel
Left Channel
Left Channel
Left Channel
16
15
18-bit LSB Justified Format with DSIZ = 1 and JUST4:0 = 01110.
16-bit LSB Justified Format with DSIZ = 1 and JUST4:0 = 10000.
MSB/LSB Justified Format with DSIZ = 0 and JUST4:0 = 00000.
MSB B14
17
16
LSB
I
I
2
2
S Format with DSIZ = 0 and JUST4:0 = 00001.
S Format with DSIZ = 1 and JUST4:0 = 00001.
13
17
13
18
B2
14
18
14
30
B1
B1
B1
15
15
31
31
LSB
LSB
LSB
B1
16
32
16
32
32
MSB
LSB
1
1
1
1
1
MSB
MSB
B15
2
2
2
B14
B14
MSB B16
3
3
3
16
15
Right Channel
Right Channel
Right Channel
Right Channel
Right Channel
MSB B14
17
16
LSB
13
17
13
18
B2
14
18
14
30
B1
B1
B1
15
15
31
31
LSB
LSB
LSB
B1
16
32
16
32
32
4109L–8051–02/08