I2C read not being acknowledged - Apple Authentication Co-processor

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I2C read not being acknowledged - Apple Authentication Co-processor

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ruchisirauthiya
Contributor II

Hello,

I am working on iPod Authentication Coprocessor 2.0C (MFI337S3959).

With source code in 'i2c-imx.c', I2C probe and writes are working fine but I2C read is failing. 'i2c_imx_read' is returning after checking for ACK in the function 'i2c_imx_acked'.


We have observed on the scope that for SCL bit-8 (acknowledge), SDA remains low for the read operation and thus there is no acknowledge. Bit-8 for write operation remains low for ACK, which is the correct.

What could be causing read not to be acknowledged? Is there a work around?


Thanks and Regards,

Ruchi

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ruchisirauthiya
Contributor II

Solved. Used retry mechanism when NACK is received.

View solution in original post

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lavakumars
Contributor IV

hi,

i am also having the apple authentication module trying to use it on imx6qp board ,

but the module is not at all detected . can someone tell how to proceed (#imx6qp) further.

Got the patch from nxp for mfi drivers but no use.:(

Regards,

Lavakumar S

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mohammadzahabsh
Contributor I

Hey,

  Can anyone help me as ho to install apple auth chip on imx series boards.

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kumarmn
Contributor I

For this same chip I have got the acknowledgement for the slave address but I found NACK for first time i2c_writes & for every i2c_reads.As you said I retried with 500ms delay then I received ACK(for the 2nd retry)  for both i2c_reads & i2c_writes.

I have few queries here,please clarify:

Is this retrying model a fix or only a work around?If there exists a solution kindly let me know.

How many retries were done in your case to get the ACK?

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ruchisirauthiya
Contributor II

Solved. Used retry mechanism when NACK is received.

View solution in original post

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