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  1.    #1  
    I'm an embedded computer hardware/software engineer. One of the things that interests me is making my gadgets talk to each other and exchange data.

    So in the course of fooling around making my GPS'es exchange data with the treo I discovered something slightly interesting. On page 777 of the T600 developer's guide it gives the pinout for the connector on the bottom. I have a serial data cable from the T300 that works with the T600 (*with some issues). Based on this guide and the fact that the data cable works with some modification, I assumed that the treo output low level (TTL) RS232 and the cable sucked power from the host serial port to do the inversion / level shifting necessary to talk to a real serial port. I took the data cable apart out of curiousity and the chip inside the data cable is a MAX3221, an I2C to RS232 converter. So the signal coming out of the Treo is actually an I2C data protocol that gets converted to RS232 inside the cable.

    The questions are:
    I need to get out my protocol sniffer and an ohmmeter and ring out the connections but it appears (to me) that the developer guide is wrong. See the descriptions of RXD and TXD on page 777.

    If it really is an I2C interface, it could be pretty cool to manufacture some custom interfaces. I haven't gotten familiar with the low level OS interface but I wonder how hard it would be to get access to the I2C lines?

    Paging Potatoho, I know you know a lot about this.

    David
  2. #2  
    Yes, very geeky, indeed. Can you translate the above to English so the rest of us can understand what you're talking about? Basically "what can that do for me?"

    Thanks.
  3. Ursa's Avatar
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    #3  
    I am no EE, but I'll give it a shot.

    Essentially, David went poking around and found out that there may be more functionality out of the serial port for the Treo than might be indicated by the term "serial port". David is further noting that the official documentation does not indicate that there is more there.

    What does this mean for us mere mortals? Very little, actually, for now. A proper gEEk will need to poke and prod the Treo's serial port to determine what additional functionality can be "unlocked", and then someone will need to make hardware that will use it.

    Later,
    Bill
  4. #4  
    So... at the end of the day we may be able to use our Treo 600 for..... ?
  5.    #5  
    I2C (pronounced "I squared C") is a way for two devices to exchange binary data over a 2 wire interface. One interesting point is I2C is a bus protocol, meaning multiple devices can all sit on the same bus and the treo could talk to them all through the same two wires. Unlike a serial port that is just a one device to one device protocol.

    What could you do? It depends on how hard Handspring makes it to access these lines. But assuming you could figure out the drivers there are a number of "neat tricks".

    I have a part on order for my job right now that is an I2C to Bluetooth transceiver. So you could (in theory) build a Bluetooth "add on" but it would be a lot of work to write all the drivers and stacks.

    You could wire up a car cradle that talks to your cars OBDT port and gives you real time diagnostic data from your car's computer.

    You can buy a number of temperature probes that have an I2C interface and you could build a sensor network.

    I even think there are some A to D converters with an I2C interface that you could build your own data acquisition circuit.

    On a plus side, If the Treo 610 turns out to be real I bet it uses the same I2C bus. If so you might be able to access the Bluetooth stacks at a hardware level and do some more neat tricks.

    Can you believe I get paid to do stuff like this? I love my job.

    David
  6. #6  
    Quote Originally Posted by djs_tx
    On a plus side, If the Treo 610 turns out to be real I bet it uses the same I2C bus. If so you might be able to access the Bluetooth stacks at a hardware level and do some more neat tricks.
    David
    So does that mean that it may be possible to use the Treo610 (If it exists with bluetooth) as a BlueTooth adapter with my desktop. Like I can use (Sort Of) the Treo600 as a wireless modem...
    Palm III > Palm IIIC > Handera 330 > Kyocera 6035 & Sony NR70V > Treo 600 > Treo650 & Palm LifeDrive > Modded LifeDrive w/16gig CF > Palm Pre
  7.    #7  
    Yeah, you could but you'd spend a heck of a lot more time and money to set it up than it would cost just to buy a $40 BT adapter. Plus your data speed through I2C is nothing compared to USB.

    David
  8. #8  
    I was just speaking in theory. You never know how creative some people are.
    Palm III > Palm IIIC > Handera 330 > Kyocera 6035 & Sony NR70V > Treo 600 > Treo650 & Palm LifeDrive > Modded LifeDrive w/16gig CF > Palm Pre
  9. Jessop's Avatar
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    #9  
    djs_tx: send me a PM if you find any more I am very interested in what you have found so far.

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