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diff --git a/Documentation/sound/alsa/soc/DAI.txt b/Documentation/sound/alsa/soc/DAI.txt deleted file mode 100644 index c9679264c55..00000000000 --- a/Documentation/sound/alsa/soc/DAI.txt +++ /dev/null @@ -1,56 +0,0 @@ -ASoC currently supports the three main Digital Audio Interfaces (DAI) found on -SoC controllers and portable audio CODECs today, namely AC97, I2S and PCM. - - -AC97 -==== - - AC97 is a five wire interface commonly found on many PC sound cards. It is -now also popular in many portable devices. This DAI has a reset line and time -multiplexes its data on its SDATA_OUT (playback) and SDATA_IN (capture) lines. -The bit clock (BCLK) is always driven by the CODEC (usually 12.288MHz) and the -frame (FRAME) (usually 48kHz) is always driven by the controller. Each AC97 -frame is 21uS long and is divided into 13 time slots. - -The AC97 specification can be found at :- -http://www.intel.com/p/en_US/business/design - - -I2S -=== - - I2S is a common 4 wire DAI used in HiFi, STB and portable devices. The Tx and -Rx lines are used for audio transmission, whilst the bit clock (BCLK) and -left/right clock (LRC) synchronise the link. I2S is flexible in that either the -controller or CODEC can drive (master) the BCLK and LRC clock lines. Bit clock -usually varies depending on the sample rate and the master system clock -(SYSCLK). LRCLK is the same as the sample rate. A few devices support separate -ADC and DAC LRCLKs, this allows for simultaneous capture and playback at -different sample rates. - -I2S has several different operating modes:- - - o I2S - MSB is transmitted on the falling edge of the first BCLK after LRC - transition. - - o Left Justified - MSB is transmitted on transition of LRC. - - o Right Justified - MSB is transmitted sample size BCLKs before LRC - transition. - -PCM -=== - -PCM is another 4 wire interface, very similar to I2S, which can support a more -flexible protocol. It has bit clock (BCLK) and sync (SYNC) lines that are used -to synchronise the link whilst the Tx and Rx lines are used to transmit and -receive the audio data. Bit clock usually varies depending on sample rate -whilst sync runs at the sample rate. PCM also supports Time Division -Multiplexing (TDM) in that several devices can use the bus simultaneously (this -is sometimes referred to as network mode). - -Common PCM operating modes:- - - o Mode A - MSB is transmitted on falling edge of first BCLK after FRAME/SYNC. - - o Mode B - MSB is transmitted on rising edge of FRAME/SYNC. |