# SGTL5000 codec - No PCM or I2S Tx output from WP8548

**URL:** <https://mangoh.discourse.group/t/sgtl5000-codec-no-pcm-or-i2s-tx-output-from-wp8548/1091>\
**Category:** mangOH Green\
**Created:** [January 22, 2018, 1:48pm UTC](https://mangoh.discourse.group/t/sgtl5000-codec-no-pcm-or-i2s-tx-output-from-wp8548/1091 "2018-01-22T13:48:15Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![GeO](https://avatars.discourse-cdn.com/v4/letter/g/f4b2a3/32.png) [@GeO](https://mangoh.discourse.group/u/GeO)\
**Post date:** [January 22, 2018, 1:48pm UTC](https://mangoh.discourse.group/t/sgtl5000-codec-no-pcm-or-i2s-tx-output-from-wp8548/1091/1 "2018-01-22T13:48:15Z")

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Hi,

I am currently working on an extension board providing an external audio codec (using the PCM output available on the IoT connector).  
For now, I am focused on the Linux kernel modification in order to detect and initialize the codec but this is not a 2 days work.  
For now I managed to initialize the codec through I2C and get a PCM clock on the IOT pin but I do not see any PCM data going to the codec.

I am not sure if I am on the right way to achieve my goal.

Is there some tips/good practices to do that ?

Best Regards