Ameba-D User Manual
User Manual All information provided in this document is subject to legal disclaimers. © REALTEK 2019. All rights reserved.
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22
Inter-IC Sound (I
2
S)
22.1
Introduction
Inter-IC Sound (I
2
S) is an electrical serial bus interface standard used for communication with digital audio devices. It communicates audio data
between integrated circuits in an electronic device. The I
2
S bus separates clock and serial data signals, resulting in a lower jitter than typical
communications systems which recover the clock from the data stream. The I
2
S is widely used in various multimedia systems.
The I
2
S can operate in slave or master mode, as a receiver or a transmitter. It can address three different audio standards including the I
2
S
Philips standard, the Left-justified standard and Right-justified standard.
22.2
Features
Sample bit: 16-bit, 24-bit, 32-bit
Sample rate: 8K, 12K, 16K, 24K, 32K, 48K, 64K, 96K, 192K, 384K, 7.35K, 11.025K, 14.7K, 22.05K, 29.4K, 44.1K, 58.8K, 88.2K, 176.4K
I
2
S throughput: 0.2352Mbps (7.35K * 32bit) ~ 24.576Mbps (384K * 64bit)
I
2
S channel number: mono, stereo, 5.1 channel
Sample bit for mono: 16-bit, 32-bit
Sample bit for stereo & 5.1 channel: 16-bit, 24-bit, 32-bit
Integrated DMA engine to minimize the software efforts
Master or slave mode
Mono and stereo Tx or Rx, or Tx & Rx mode
5.1 Tx mode (DAC), Rx mode (ADC) not supported
Not for PCM mode
Mute function
22.3
Interface
The external interface of I
2
S is I
2
S out, which contains Master Clock (MCK), Serial Clock (SCK), Word Select (WS) and Serial Data (SD). As for I
2
S
out, according to different channel number of audio data, the configuration of it varies. For mono and stereo audio, SD regards SD_i as input
and SD_o as output. Fig 1-1 shows I
2
S mono/stereo audio-out interface configuration. For 5.1 channel audio, because Ameba-D only supports
5.1 Tx mode, SD contains SD0, SD1, SD2 as output without input. SD0 transmits audio data in the left channel(A) and the right channel(A), SD1
transmits audio data in the left channel(B) and the right channel(B), and SD2 transmits audio data in the left channel(C) and the right
channel(C). Fig 1-2 shows I
2
S 5.1 channel audio-out interface configuration.
I2S out
control
I2S
DAC/ADC
MCK
SCK
WS
SD_o
SD_i
Fig 22-1 I
2
S mono/stereo audio-out interface configuration
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2019-05-15 10:08:03