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MattTheGeek

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Posts posted by MattTheGeek


  1. Have you read the system integration manual for the GSM radio? if not, give it a read here (pay close attention to chapter two). The GSM radio is fairly picky. 

     

    Are those sensors on breakout boards? 

     

    That's all i can see right now, i'll take a more detailed look later.

     

    Design

    I'd recommend adding a reset switch for your MSP430. You need ESD protection for the SIM card.

     

    Any reason you need or want the DHT22? I really don't trust that sensor line for accurate measurements. 

     

    Switch your UART line! It should look like this: 

     

    _MSP430__                 _GSM RADIO_

    |                  |                 |                        |

    |                  | TX -> RX  |                        |

    |                  | RX <- TX  |                        |

    |_________|                 |____________|

     

     

     

    Crystal

    C2 and C3 are not needed. The UCS provides load capacitors up to 12pF.

    In fact that 32Khz crystal is not really needed. The UCS has a REFO clock source that can provide a 32Khz clock signal. I'd still would leave the crystal footprint in though so that it could be added at a later time if required.

     

    Power

    I would recommend replacing C7 with a 100uF tantalum capacitor. That GSM radio requires a lot of power when transmitting. Also consider providing reverse current protection if you think it may happen. the GSM radio does not have any reverse current protection.

     

    Follow the recommendations on reducing noise and EMI from the radio, as this could affect your analog components. The reset line seems to be really susceptible to EMI.


  2.  

    Which was interesting - is there something similar for the MSP430?

     

     

    Do you mean a rule sheet specific to the MSP430 or a rugged MSP430 development board? In any case, replacing the MSP430 or launchpad might be a cheaper solution.

     

     

     

    I was interested because I read somewhere that if you need more current on a pin than the MSP430 can supply, you can tie it to VCC and make the pin active low instead, but I would figure you'd need Fix #1 that they recommend (but with a lower rated Zener diode) to make it work reliably. 

     

    Wouldn't a darlington transistor pair work as well?


  3. Are there any outstanding issues with the current LP silicon that may stop us from prototyping.

     

    There isn't any device crippling bugs, but there are some that may be annoying now and perhaps later in the future.

     

    But Just out of curiosity, Did anyone get a XMS430G2231 or XMS430G2211 when the MSP430 value line LaunchPad first came out? The only development/eval kit from TI that had experimental silicon was the Chronos.


  4. Makes for a good reason for me to keep one in the box.

    Unfortunately, I opened the 2nd box so I could check the silcon revision there.

     

    You can try returning the launchpad, since you have a LX4F and not a LM4F.

     

    "Should this evaluation board/kit not meet the specifications indicated in the User’s Guide, the board/kit may be returned within 30 days from the date of delivery for a full refund." (See http://www.ti.com/lit/ml/sszz027b/sszz027b.pdf)


  5. whilst we are on the subject of clocks has anyone carried out measurements on how accurate and stable the 32K768 crystal included with the MSP Launchpad kit is? I have a need for a fairly precise clock for an application. An option I have used with an AVR is to derive the time from a GPS board with a 1 pulse per second output. But if the 32k768 crystal is accurate enough and stable enough may be I don't need to do this.

     

    Regards, Steve

     

    The tolerance of the crystal provided with the launchpad is +/-20ppm (or 0.002%). It's not the best, but it works.


  6. Link?

     

    I ordered this one. You can find others by going to the analog products, then sort by lowest price. five or so free boards will come up, along with lots of $5 boards. The boards are 'demonstration fixtures'... But i'm sure they can be hacked for other unintended purposes.


  7. I wonder what that means, "Shipped Partially"?

     

    Nice pretty box and no board inside? ;)

     

    Whatever. :rolleyes: I'm jealous.

     

    At least your's is partially shipped; you ordered the day before me and have the same ship date.

     

    post-256-0-73909100-1352446131.jpg

     

     

     

    I wouldn't be surprised if all those people that only ordered ONE board screwed up TI's distribution system.

     

    :D:P:o:angry::mellow::ph34r:

     

    I just ordered a 'free' bare breakout board along with the Stellaris boards. The breakout board shipped the same day.


  8. s1ck,

     

    The default reference voltage for analogRead() is well, DEFAULT (Which is using the internal VCC and VSS). It can be changed by using the function analogReference(). As for reading the exact reference voltage, I don't think that's possible. (Other than setting the ADC10 to output the reference voltage and using a voltmeter to read it)


  9. [bug5]

    It appears that phpbb doesn't really delete private messages, so every message from the old board was transferred to this one, overfilling our PM boxes and not allowing us to send or receive PMs.

     

    [Request1]

    Is there any way to archive those messages, so we don't have to permanently delete them? Or even better, increase the quota?

     

    [Request2 or Bug6]

    It appears that uploading is not allowed. Can you lift that restriction?

    "You can upload up to Uploading is not allowed of files (Max. single file size: 2MB)"

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