AT80C51SND1C-ROTIL Atmel, AT80C51SND1C-ROTIL Datasheet - Page 77

• Manufacturer Part Number: AT80C51SND1C-ROTIL
• Description: IC MCU FLASH MP3 DECODER 80-TQFP
• Manufacturer: Atmel
• Series: 80Cr

Specifications of AT80C51SND1C-ROTIL

• 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 Type: ROMless
• Ram Size: 2.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.3 V
• Data Converters: A/D 2x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 80-TQFP, 80-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Program Memory Size: -
• Other names: AT80C51SND1CROTIL

14.5
14.6
14.7
4109L–8051–02/08
MP3 Buffer
Interrupt Request
MP3 Song Playing
Table 84. Sample Duplication Factor
In song playing mode, the audio stream comes from the MP3 decoder through a buffer. The
MP3 buffer is used to store the decoded MP3 data and interfaces to the decoder through a 16-
bit data input and data request signal. This signal asks for data when the buffer has enough
space to receive new data. Data request is conditioned by the DREQEN bit in AUDCON1 regis-
ter. When set, the buffer requests data to the MP3 decoder. When cleared no more data is
requested but data are output until the buffer is empty. This bit can be used to suspend the audio
generation (pause mode).
The audio interrupt request can be generated by 2 sources when in C51 audio mode: a sample
request when SREQ flag in AUDSTA register is set to logic 1, and an under-run condition when
UDRN flag in AUDSTA register is set to logic 1. Both sources can be enabled separately by
masking one of them using the MSREQ and MUDRN bits in AUDCON1 register. A global enable
of the audio interface is provided by setting the EAUD bit in IEN0 register.
The interrupt is requested each time one of the 2 sources is set to one. The source flags are
cleared by writing some data in the audio buffer through AUDDAT, but the global audio interrupt
flag is cleared by hardware when the interrupt service routine is executed.
Figure 14-5. Audio Interface Interrupt System
In MP3 song playing mode, the operations to do are to configure the PLL and the audio interface
according to the DAC selected. The audio clock is programmed to generate the 256·Fs or
384·Fs as explained in Section "Clock Generator", page 74. Figure 14-6 shows the configuration
flow of the audio interface when in MP3 song mode.
DUP1
AUDSTA.6
AUDSTA.7
0
0
1
1
UDRN
SREQ
DUP0
0
1
0
1
Factor
No sample duplication, DAC rate = 8 kHz (C51 rate).
One sample duplication, DAC rate = 16 kHz (2 x C51 rate).
2 samples duplication, DAC rate = 32 kHz (4 x C51 rate).
Three samples duplication, DAC rate = 48 kHz (6 x C51 rate).
AUDCON1.4
AUDCON1.5
MUDRN
MSREQ
EAUD
IEN0.6
AT8xC51SND1C
Audio
Interrupt
Request
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