• EEVblog #134 – The Maxim Manipulation

    More dodgy components, this time from our friends at Maxim (c/o Motorola)

    The DS2502 datasheet is HERE

    Maxim have admitted the problem and have fixed everything without fuss.

    It turns out the firmware is intended for Motorola phone batteries:

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      • Adrian

        Hahaha, this is great Dave. You got a load of pre-programed ID chips for rechargeable Motorola cellphone battery packs. It has even been patented.

        Per the patent, the data is identified as:

        Each page includes a data checksum, a battery identification code and related charging and discharging parameters that pertain to a particular type of battery, such as for example nickel-cadmium (NiCd), nickel-metal hydride (NiMH), alkaline, or lithium ion batteries. The first page contains data for FDMA portable devices, the second page data for TDMA portable devices, the third page data for desktop chargers, and the fourth page data for a predetermined multi-character message. In the preferred embodiment, the predetermined message is: “COPR1996MOTOROLA – – E.P – – CHARGE – – ONLY”.

        Not a fake, someone probably forgot to turn off the pre-programming on the taping line….

        • http://www.eevblog.com EEVblog

          Nice find, thanks!

      • Anthony

        Is the name of this Episode inspired by the ‘Big Bang Theory’s naming convention? =)

        • http://www.eevblog.com EEVblog

          I have no idea what you are talking about :->

          • Anthony

            “Season 4 – Episode 1 – The Robotic Manipulation – aired: Fri, Sep 24, 2010”

            +) Cyclops smiley

          • Ondre


            • Anthony

              Yeah I think it was =)

              • Ivan

                But, was that sarcasm?

      • SockThief

        On a similar thread, Bunnie Huang had an experience with Official Kingston Memory Card which were dodgy, the article
        is well worth a read.

        Maxim have admitted they are responsible, but haven’t said how it happened…

      • Michael Thompson

        Stuff happens.

        Sorry something else came up on ya Dave.
        Wow trials and tribulations.

        Way more even handed on this entry too.

      • Robert

        It also looks like the bad chip was not RoHS compliant – there was no plus sign on the package.

        • Karl (not that Karl, the other Karl)

          Someone found some reels in a closet, and restocked them in the warehouse, not looking at any details.

      • Anthony

        I wonder how much those chips would be worth to Battery counterfeiters =)

      • ROHSCompliantFoot

        Slightly OT: Re: Rereeling practices: Would be great if done honestly! Reuse before recycling. Now could all the eco stereotypes please have a w**k over that.

        @Anthony not more than the pristine, writable chips I guess.

      • Ryan

        David, you don’t like Maxim parts? I love Maxim parts. Their catalog always seems to have the exact 8-pin mixed-signal doodad that I need for my circuit. Maxim has lovely parts, I tell you. It’s their availability that sucks!

        When the Maxim’s web store quotes you “99 WKS Lead Time”, you *know* they’re just messing with you.

        Dump those Maxim parts and go with something from a manufacturer that takes care of smaller customers and hobbyists. How about a nice Microchip 24AA02E48? It has a unique 48-bit MAC address, double the storage, a standard I2C interface, and you can reprogram it a million times. Digikey has 45,000 in stock for $0.22/ea. I bet you’re paying a buck apiece for those DS2502s.

        • http://www.elvtechnology.com.au Shaun Clarke

          I may be wrong here, but isn’t the fact it’s a write once cheap an intended feature?

          For example, to stop the end user being able to ‘hack’ or modify parameters that may be stored there like say serial numbers by reprogramming it again after the initial programming?

        • http://www.eevblog.com EEVblog

          Availability is the real reason I don’t like Maxim parts.

          An I2C interface requires twice as many lines as the DS2502, and believe it or not that can be a deal breaker!
          And you often can’t just change chips like that willy-nilly, other factors can come into play like backward system compatibility.
          Some choices can be more complicated than they first appear.

          • Ryan

            11AA02E48 uses one I/O, although I don’t think it’s compatible with 1-wire. But think of all those cute little I2C sensors and peripherals out there. You know you want them.

            Isn’t it surprising how hard it is to get unique data onto each board, in a production environment? Especially if it needs to match a sticker or something. Getting an overseas manufacturer to put a barcode sticker on the board and put the barcode data into that board’s EEPROM, and have it actually MATCH… oh my god. It’s not even a communication problem

      • Ryan

        Maybe for Rigol.

        As for myself, I’m quite in favor of hacking and modifying parameters. And a DS2502 wouldn’t stop me for a moment

        • Ryan

          (The real reason you can’t reprogram a DS2502 is because it’s a 15 year old part based on technology borrowed from UV EPROMs. Nobody would release a part like that today.)

      • djsb

        Where can the 1 wire readers be bought or are there any DIY designs available anywhere? Thanks.

        • chrisindallas


          Serial and USB 1-Wire interfaces can be purchased from Dallas Semi/Maxim like the DS1402 or DS9490R. It can also be bit banged pretty easily.


      • Wonko The Sane

        David, your not having much luck with components at the moment are you…

        Maybe you should become a Monk….

        (I don’t think you would get into a silent order…)

        – Anyway – To all your reader

        Merry Christmas and a Happy New Year.

        • http://www.eevblog.com EEVblog

          Twice in the one week was extraordinary bad luck!

      • Frank

        I like the mini microscope. Have you reviewed it yet? Google tells me its a bit pricey though.

      • http://hackedgadgets.com Alan Parekh

        Hey Dave,

        I see by your update text that they fixed the issue. The thing that always gets me is a handful of new parts hardly makes up for the time and effort that was incurred because of their mistake.

      • Steve Zvosec

        Hey Dave,

        Where can you get one of those blue boards that you mounted the DS2502 on? Looks like it would make a great breakout board for a lot of different footprints.

      • Leigh

        I made a decree for our engineers not to design in Maxim parts because of the nightmares production has with availability. Mind you the engineers occasionally sneak one in now and then….

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