Unknown chip manufacturer?

[sokot13]

Hello,

Here is a photo of an unknown IC, from a consumer product from 2024. It embeds functions for reading from a SDCard, "decrypting" audio files, read analog inputs from various buttons, perform DAC. There are only two other chips on the board including one op amp. The sdcard only contains "encrypted" audio files, no software.

I did not find any information about this manufacturer, this logo is unknown to me.

The only markings are ECP390Y_I 2225UDZ and this "XX" logo.

Any ideas?

[GGMM]

Hello,

not found also.  Xicor??
an interisting link
https://componentstash.com/reference/semiconductor-logos

cdt

[PA0PBZ]

Appotech: https://www.appotech.com/

Probably a custom part nr.

[sokot13]

Thank you! This chip reads a audio files in a special format, which is probably a known format encrypted in some way.

[fzabkar]

Perhaps it's a custom version of this IC (AX1070, 16KB OTP + 5376B IRAM)?

https://gesigor.ru/pdf/AX107X.pdf
https://datasheet4u.com/download_new.php?id=1261671

https://gw.alicdn.com/imgextra/i2/1839037961/O1CN01hthnDu28gBeB7RBVF_!!1839037961.png  (photo)

[sokot13]

Good find!

Files are probably encrypted with a simple algorithm, given the capabilities of the chip. They look like MP3 files without header, with raw frames whose length match 128kbps/48kHz. The frame header is 090D62F2 (instead of FFFB9440?) and when there is silence we have 0x5C instead of 0x00 in the frame's data section.

[fzabkar]

If the data isn't sensitive, could you upload the first sector? Perhaps it's an XOR algorithm of some kind??

  0x090D62F2 XOR 0xF6F6F6F6 = 0xFFFB9404

This MP3 hex dump has 0xFFFB9404 instead of 0xFFFB9440:

https://weichao.io/cabbeea21c77/

[sokot13]

Nice find!! It works, now the audio files can be decoded. And the content of the memory card can be replaced by my own audio files :-)

[fzabkar]

I don't understand. What happens to the 0x00/0x5C bytes in the quiet areas? :-?

[m k]

Huffman bits?

[fzabkar]

I'm thinking that 0x5C XOR 0xF6 = 0xAA, not 0x00. Therefore, I'm wondering if the XOR byte varies throughout the file. :-?

[sokot13]

I was wrong, it should be 0xAA not 0x00. It was the trailing frames of the MP3 file.

As for the XOR byte, no it is constant through the file, and the key is the same for all the files.