I bought this car mp3 (MP3-CD/MMC/SD/USB/radio) player during summer of 2005. It was relatively cheap, and most importantly, it had a SD/MMC card slot.

Yakumo has a German-speaking support forum here:
http://forum.yakumo.de/german/index.php?t=thread&frm_id=123&

This car radio was also sold in a near-identical version by Aldi-Sued in Germany under the name “Tevion …???” but without a remote control.

It has the ability to record from radio/line in/CD/… and encode to MP3 in real-time. (Nice for recording from radio).

It appears that there's one bug, namely that the CD drive sometimes stops reacting. When this happens, it wont accept/eject/play CDs. When this happens, pressing the reset button brings it back to life, but of course the radio station memory keys loose their information…

Here are some misc stuff I found out about the unit:

• The Main Board uses a ST7 microcontroller: ST72F321.
  • Datasheet here: http://www.st.com/stonline/books/pdf/docs/7599.pdf
  • Forum here: http://mcu.st.com/mcu/modules.php?mop=modload&name=Splatt_Forums&file=viewforum&forum=1
• The USB/MMC/SD seems to be controlled by a board with
  • SST 39VF800A
    • “Multi Purpose Flash” memory
    • http://www.sst.com/products.xhtml/parallel_flash/39/x16/SST39VF800A
    • http://www.sst.com/downloads/datasheet/S71117.pdf
    • 512K x 16 (8MBit)
  • Samsung K4S161622H
    • http://www.samsung.com/Products/Semiconductor/DRAM/SDRAM/SDRAMcomponent/16Mbit/K4S161622H/K4S161622H.htm
    • Datasheet: http://www.samsung.com/Products/Semiconductor/DRAM/SDRAM/SDRAMcomponent/16Mbit/K4S161622H/ds_k4s161622h_rev15.pdf
    • 512K x 16Bit x 2 Banks SDRAM =⇒ 1Mx16
  • Telechips TCC720A
    • Appears to be a MP3 decoder chip, based on a ARM940T
    • http://www.telechips.com/product/product_mp3_tcc72x.htm
    • apparently, the datasheet is not publicly available
    • has an on-chip stereo DAC
    • can interface: IDE, USB, IrDA, SRAM, DRAM, Flash, …
    • has a JTAG interface.
• The interface board thats piggy-backed onto the board with the Flash/DRAM/TC720 has
  • a SD/MMC card slot
  • the USB connector
  • two voltage regulators:
    • a 7805 LDO voltage regulator
    • a SAC15x0 (x is not readable, but probably a 0)
      • Up&Down Multi Voltage Regulator
      • can deliver up to 1000mA
      • more info here: http://www.cosmodesign.com/english/analog/udmvreg.htm
  • and a WM8725 (WM8725GED) stereo audio DAC
    • http://www.wolfsonmicro.com/products/digital_audio/dacs/WM8725/
    • Datasheet: http://www.wolfsonmicro.com/uploads/documents/WM8725.pdf

• The CD Drive takes up the most space, but can be removed quite easily with just four screws and one flat cable (24pin). It was made by Komec
  • http://www.komec.com.cn/eabout.htm
  • Seems to be a CDX-100 Series. (Although I can't exactly identify which one). http://www.komec.com.cn/eproduct.asp?classid=&Page=1
  • It uses a Toshiba TC94A14 chipset
    • http://www.semicon.toshiba.co.jp/openb2b/websearch/productDetails.jsp?partKey=TC94A14FA
    • Datasheet: http://www.alldatasheet.com/datasheet-pdf/pdf/TOSHIBA/TC94A14FA.html

While taking it apart, I took lots of pictures: http://projects.varxec.net/images/yakumo/gal/yakumo_car_mp3_galleryidx.html
(I also put it back together, and it still works )

Where to buy:

• http://www.amazon.de/exec/obidos/ASIN/B0009MZ7P2/302-7243173-7480049
• http://www.reichelt.de OrderNo: YAK HYPERSOUND C