Shop OBEX P1 Docs P2 Docs Learn Events
sx28 resetting...power supply? — Parallax Forums

sx28 resetting...power supply?

prozachprozach Posts: 11
edited 2007-09-06 17:52 in General Discussion
I am having a problem with my sx28 chip resetting occasionally.· I am not sure if this is happening while the chip is in operation or during power up/down.· I have about 50 of my circuits in the field with a failure rate of about 1 every two weeks.· The circuits operate about 12hrs a day.

I am using a ATX power supply that seems to power down slowly.· Could this be the problem?·· I have the circuit directly connected to the ATX with no filters.

Zach














·

Comments

  • BeanBean Posts: 8,129
    edited 2007-09-03 17:46
    Zach,
    Are you using a 10K resistor on the MCLR pin ?
    Are you using a brown-out reset setting on the device line (like "BOR42") ?

    Bean.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    The first rule to being successful is "Learn from your mistakes",
    The second rule is "Be willing to make mistakes"
    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    www.hittconsulting.com
    ·
  • prozachprozach Posts: 11
    edited 2007-09-03 19:37
    I do have a 10k to vcc on the MCLR pin. I did not create the board or program so bear with me. I do not believe there is a brown-out setting on the device line. Can you explain further?

    Thanks

    zach
  • prozachprozach Posts: 11
    edited 2007-09-03 20:13
    Just to clarify.· When I say reset, I mean the program erased from the chip. After reprogramming the chip everything is fine.
  • PJMontyPJMonty Posts: 983
    edited 2007-09-03 20:51
    Prozach,

    When your chip "resets", do you do a read and verify of the code and the IDE says that the code in the chip isn't matching the code in the IDE?

    Thanks,
    PeterM
  • prozachprozach Posts: 11
    edited 2007-09-06 15:05
    I just received two bad chips to diagnose. With both chips I tryed rerecording the firmware. The recording went fine, but when they were reinstalled the chips were non fuctional. So my thought is something blew in the chips.

    I can think of two sources for this. One is a small motor that runs on the 12 volt line of the power supply. The second is the actual power supply itself.

    What do you think?
  • CCraigCCraig Posts: 163
    edited 2007-09-06 15:28
    If you are able, you might check the outputs of the pins controling the motor. Just a guess, but you might be getting some sort of back EMF from the motor which are blowing the outputs. In light of the fact that they record fine, that's my guess.

    HTH, Chris

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    I'm not scared of your robot. I'm covered by Old Glory (youtube)
  • PJMontyPJMonty Posts: 983
    edited 2007-09-06 17:52
    Prozach,

    You didn't answer my question. Did you do a verify on the "reset" chips and find that the program was erased? It now sounds like your problem isn't that the program was erased as you first indicated, but that you have damaged I/O lines. In order to determine that the chip's program was erased, you need to verify this using the tools you already have, otherwise you're just guessing.

    Thanks,
    PeterM
Sign In or Register to comment.