I just implemented a feature for the STM8 firmware to allow the usage of Patches for the Audio DSP – provided by VLSI.
It is known that in its unpatched state the VS1063 has some sligtly samplerate issues with 44100, 22050, and 11025 samplerates (about
2% 0,23% Error) – VLSI published a patch to overcome this issue. This is now integrated in the stm8 firmware. More specifically the patch from the .plg File is stored at Offset 0xa006. At 0xa000 the Firmware is looking for the Magicstring “VlSi” and at 0xa004 the size of the patch in words is stored.
If you ever wondered what endianness is used to store larger than 8bit values on the STM8 I can tell you that using the IAR compiler the STM8 is Big Endian.
I also observed some strange behaviour with the OggStreamer Hardware loading the patch sometimes pushed the VS1063 into a deadlock (DREQ-Line was hold low) – for more infos check the vsdsp-forum.
There are already some OggStreamers out in the wild – to update these devices without disassembling and reprogramming them with an ST-Link the stm8flasher tool is needed, which is already in the pipeline.
With this update it will be possible to do pitch-correct streaming for all datarates (8000, 11025, 16000, 22050, 24000, 32000, 44100 and 48000)