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IS1621N on BCK-08 PCB

In other cheap Chinese device news here’s DealExtreme p/n 8422 with the case removed, powered by a benchtop supply, peered to my Nexus One, and playing audio. I’m hoping to redo the output circuitry on this and put it in another case to make a decent Bluetooth audio device for connecting to either a home or car stereo. It runs off of 3.7 VDC and has an on-PCB antenna, so it should be pretty easy to work with.

The PCB contains an I.S.S.C. IS1621N and FM24C08B EEPROM, which likely contains the IS1621N’s config. I’ve requested the data sheet for the chip from I.S.S.C., so hopefully I’ll have that soon and can work on it. I’d also like to change the identifier string in the EEPROM, but I probably won’t touch that until I know what the IS1621N expects to find in other parts of it. I also hope to find an example implementation, as it should be easy to build off of that to get line level output.

Here’s a few more pictures of the board:

· Detail of the FM24C08B EEPROM which likely houses the config for the IS1621N on the BCK-08.
· Top / button side of the BCK-08 PCB.
· Bottom / component side of the BCK-08 PCB showing the I.S.S.C. IS1621N Bluetooth IC and FM24C08B EEPROM.

23 Comments

  1. John
    John January 20, 2010

    Wow, I am looking to do the exact same thing. I just opened my BCK-08 from Dealextreme and searched IS1621N and found your post. Could you keep me informed of your progress. Nice pics. I noticed that the audi quality wasn’t up to par. I would like to add this to the x-mini max ii speakers (which I haven’t aquired yet).

  2. c0nsumer
    c0nsumer January 23, 2010

    John: Ha, wow. Funny, that. I haven’t done much with it, but thus far I’ve found that it seems to be a lot more stable with peering when powered from something other than its own battery. I’ve also had a bit of weirdness with the charger on one of my two, as it just seems to stop charging after a while. One thing I’m also thinking of doing is making a small box with a mains cable coming out of one side, and a 3.5mm or dual RCA on the other. This could easily be tucked somewhere out of the way to provide BT audio to receivers, and if the buttons (at least the center one, and maybe the LEDs) are brought out to the panel, it’d remain quite usable.

  3. John
    John January 25, 2010

    Yeah, I didn’t seem to get a good charge in one of my sets off PC usb (only one tested so far). The sound quality driving my home stereo rca inputs seems to vary with the state of the charge (have to crank everything way up). With my Sony headset it sounds pretty good. I am planning to run the bck-08 off the Li-ion battery (400mah) in the X-mini speakers. Will post a comment when I get a chance to try that.
    What I really would like to do is put 1 of these in each of the X-mini speakers and drive them both from my cell (completely wireless). But I am not sure how to sync my cell with more than 1 bluetooth device. Is that why you are thinking of changing the identifier string in the EEPROM? Will that work?

  4. c0nsumer
    c0nsumer January 25, 2010

    John: I’m actually thinking of changing the string in the EEPROM simply because I can. No real other reason… I’m not sure if you can do what you are thinking of, and getting the to play in sync out of each (due to likely buffering) might be a problem.

  5. Constantin
    Constantin February 11, 2010

    Hey,

    could you send me a picture of the battery. I unsoldered mine in order to replace it with another one and forgot to how it was hooked up.

    my email is klucon2@web.de

    thx, for the help.

  6. c0nsumer
    c0nsumer February 11, 2010

    Constantin: The positive wire goes to +, the negative goes to -. I believe positive is red and negative is black, but I no longer have the battery (it appeared to be crap), so I can’t take a photo of it. Simple checking with a meter will tell you what goes where.

  7. Duncan
    Duncan February 19, 2010

    Crazy. I bought the BCK-08 with exactly the same plan in mind. Ripped it open, searched for chip info and found this blog.

    Have you had any luck getting your hands on the datasheet?

  8. c0nsumer
    c0nsumer February 22, 2010

    Duncan: Sorry, no. No luck… I’ve sort of given up on it, too. I’ve simply received no response from I.S.S.C.

  9. Massimo
    Massimo March 16, 2010

    …could you tell me what kind of battery type is mounted on adn/or what is load current?

    Many Thanx

  10. Nemno
    Nemno April 4, 2010

    seems to be the datasheet. Sorry for the splitted post.

  11. John Mak
    John Mak July 25, 2010

    would you make the datasheet in pdf format?

  12. Rotnei
    Rotnei August 16, 2010

    Hi… I also had the intention to mount a direct WiFi with this bluetooth, but the quality of the trebles is horible and the system shuts down the unit after 2 hours or use when the battery is still full (3,6V). Does anyone have the same two problems? Any solution?

  13. misterm
    misterm August 31, 2010

    any idea how to store the datasheet (apple flash bullshit)?

  14. Caleb
    Caleb October 11, 2010

    Any luck with the EEPROM, and any links to the datasheet?

  15. c0nsumer
    c0nsumer October 11, 2010

    Caleb: Sorry. I haven’t touched it in a while, and just generally lost interest. A2DP is too low quality for my tastes. Sorry.

  16. John
    John December 15, 2010

    I wanted to know if a 5vdc be given at the + – points.
    I plan to keep it powered in my car,with cigarette lighter to USB adapter
    Will this pair automatically when it get power,
    Or should u still press the button

  17. neomilium
    neomilium December 20, 2010

    Hello,
    I have sniff i2c frame with a bus-pirate and reverse a bit the dump. I had located dongle MAC address, full Class of Device (Major Service Class, Major Device Class and Minor Device Class), ID string, security PIN code (“0000”) and previously paired device’s MAC address but I can’t figure out what are others bytes.
    Note: MCU only reads the 512 first-bytes.

    You may be interested in the dump (in C): http://pastebin.com/349c23U8

  18. flowswitch
    flowswitch August 4, 2011

    I just received my BCK-08 from DX. I can confirm that it works fine from regulated +5V supply (connected instead of battery, same <10mA current consumption, no hot parts – definitely it's safe to use it this way), producing good sound. Next step is to mount it inside my kitchen minisystem to stream audio from laptop. I don't trust original pcb trace antenna also, maybe I'll try to replace it with some ceramic "inverted F" from mobile phone.

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