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Recommended IrDA transceiver for 430?

Lee Crocker
Prodigy 80 points
Other Parts Discussed in Thread: MSP430FR5739, BOOST-IR, MSP430FR4133, MSP430F2471, MSP430F2417

Just got an MSP430FR5739 board to do some testing; also got all the latest software. Unfortunately, the one thing we need it for is the one thing least documented: IrDA. The chip says it has an encoder/decoder built in, and shows register addresses, but that's about it. No sample code, no register use chart. Also, there doesn't see to be a physical transceiver on the board. TI's own transceivers seem to be all marked "obsolote". So my question is: what extra hardware do I need to test IrDA functions with this board, and is there better documentation for the encoder/decoder somewhere (perhaps with another chip)?

  • 0
    Guru 58965 points

    Furthermore, I think the IrDA encoder (in various MSP430) does not work reliably. I wonder if  could address this subject?

  • 0 in reply to old_cow_yellow
    Prodigy 80 points

    Found document SLAU272C with more info about the subsystem, but still could use some recommendation as to hardware (and of course, any user experiences or warnings). We'll be making a device that only needs to communicate with its own control unit, so if the chip's encoder/decoder is out of spec that probably won't matter as long as both ends are out of spec the same way.

    Also, we might be able to go to a 432 if we need to, though low power is a definite priority for us.

  • 0 in reply to old_cow_yellow
    TI__Guru 68116 points

    Hi Lee,

    Have you seen the BOOST-IR boosterpack and the TI Design www.ti.com/.../tidm-boost-ir-remote ? This uses something besides IrDA (it uses the IR-Modulation Logic in the MSP430FR4133 with a IR demodulator for receiving, and a couple of timers), but gives you flexibility to do a wide range of different IR protocols - see also the app note www.ti.com/.../slaa644 that talks about using that FR2xx/4xx IR modulation logic with timers for implementing different protocols.

    For IrDA, there is an app note on implementing irda with the USCI module www.ti.com/.../slaa202 that also includes example code www.ti.com/.../slaa202

    Hopefully one of these resources will help you out.

    Regards,
    Katie

  • 0 in reply to Katie Pier
    Guru 58965 points
    Katie,

    Thank you for picking this up.

    Yes, I am aware of the BOOST-IR boosterpack and will try it when I get a chance to do so. But as you said, it is for something other than IrDA.

    I have tried to use the IrDA feature in F2471 and F2417. I found that the encoding (for transmitting) works fine. But the decoding (for receiving) is buggy. It is not compatible with many existing devices that use IrDA communication. I end up only using the UART to transmit IrDA frames and use one of the Timers to do bit-baning to decode incoming IrDA frames.

    I did not see any erratum about this bug in F2471/F2417and do not know if it exist in other “IrDA capable” MSP430 or not. I welcome further clarification/discussion with TI Engineer familiar with IrDA feature.

    -- OCY
  • 0 in reply to old_cow_yellow
    TI__Guru 68116 points
    Hi OCY,

    I am not aware of any known bugs on IrDA that aren't published in the errata. If you have information you can provide about how we could reproduce the issue here (an example code + hardware setup) we would definitely want to look into it in case it's a bug that we're not aware of.

    -Katie
  • 0 in reply to Katie Pier
    Guru 58965 points
    Katie,
    The company I work with used MSP430F2471 and MSP430F2417 in one of the products. We found that the on-chip IrDA Decoder is not compatible with many existing IrDA equipped devices. For example:
    www.physio-control.com/LIFEPAK1000
    http://www.sigmapumps.com/
    We end up either add external IrDA Endec chip or use on-chip Timer to decode received IR signal. So this bug is not a problem for us. I just wonder if TI is aware of this.
    -OCY
  • 0
    TI__Guru**** 202086 points

    Lee,

    You are correct in that there is not a physical transceiver on the board.  But as far as extra hardware is concerned, it is possible to physically connect the TX and RX IrDA lines of the two communicating devices to test IrDA functionality.  After you get this working you could then move on to using external transceivers.

    All Family User's Guides have about the same amount of information regarding IrDA so I don't think that the FR57xx Family User's Guide is omitting anything.  However there are indeed no IrDA examples specifically included in the MSP430FR57xx code examples package.  I know that the MSP430G2553 code package includes three IrDA examples that could be sampled for a MSP430F5739 project since the IrDA peripherals are very similar (just be careful about naming conventions regarding the G2553 USCI vs FR5739 eUSCI).  You could try starting there and come to me if you have any questions.

    Regards,

    Ryan

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