Question about I2S Slave mode timing of i.MX6Dual SSI module.

[t-iishii]

Dear Team,

I have one question about I2S slave mode function of i.MX6D SSI module.

When SSI set to I2S slave mode, both rise and fall edge of FrameSync
timing are determined as Start of Frame (SS32 in datasheet IMX6DQCEC),
not determin as End of Frame(SS34 in IMX6DQCEC).

Is it correct?

Best regards,

Ishii.

[t-iishii]

Artur

I can't understand your answer.

You say that "The frame is exactly 2 words (time slots) long."

In I2S slave mode receive function.

It mean that

    FrameSync is used only the falling edge for start of frame.

    WL bit in SSI_SRCCR[16:13] determine the number of bit per word.

    The number of time slots per frame is fixed to 2.

    Rising edge of FrameSync has no work.

  If WL=0111b (16bit/word), after FS, 32bit data are received.

  First 16bit data is 1st word, and next 16bit is 2nd word.

The other hands,

Section 61.8.1 Operating Mode in IMX6DQRM.

It say that

    "In I2S slave mode, the programmed word length setting of the SSI can be lesser

     than or equal to the word length setting of the I2S master (external CODEC)."

  If following setting in I2S slave mode, how to work SSI?

  * 16bit word stereo data for external CODEC.

  * WL=0100 (10bits/word)

Please suggest to me.

Best regards,

Ishii.

[t-iishii]

Artur

Thank you for your quick response.

I hope to know an AC timing of the rising edge of the Frame Sync to makes the start of 2nd word.

In I2S mode, both falling and rising edge are used to start a data receive.

I think that it must be adapted both edge to SS32 timing parameter in data sheet.

which is a correct parameter for both edge timing?

Best regards,

Ishii.

[art]

No, this is not correct. In I2S mode (regardless of master or slave), the falling edge of the Frame Sync signal marks the start of frame. The frame is exactly 2 words (time slots) long. The next Frame Sync falling edge defines the beginning of a new frame.

Have a great day,
Artur

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