Sigmatel STFM1000 tuner chip

Introduction

This tuner is controlled over I2C and uses a digital audio output (most other tuners output an analog stereo signal). It also supports RDS, but it appears that this requires a lot of attention from software to decode. This tuner is used in a number of players, including the SonyNWZE360, SonyNWZE370, SonyNWZE380, CreativeZENXFi2, CreativeZENXFi3 and CreativeZENXFiStyle.

This tuner is very different from the usual tuners in that it does the bare minimum to demodulation FM, split the L+R, L-R and RDS subsignals, feed them through ADS and upload them to the SoC over a digital link, usually the proprietary DRI (Digital Radio Interface) found in the IMX233. It leave all the mono/stereo blending and RDS low-level processing to software. This requires a lot of DSP code and intricate FM knowledge.

Status

There is no code in the repository to support this tuner at the moment but a work-in-progress patch can be found on gerrit.

-- AmauryPouly - 21 Sep 2016