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bs2p40 HEATS UP — Parallax Forums

bs2p40 HEATS UP

John@PUMPKEY.COMJohn@PUMPKEY.COM Posts: 5
edited 2008-06-27 22:18 in BASIC Stamp
I have a simple circuit design that works pretty good, But sometimes when I plug it in The Stamp immediately starts to HEAT up. I have to shut it down quickly and restart it. Does anybody have any Ideas ? I have plenty of designs with the 24 pin stamp but this is my first with the 40 PIN.

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2008-06-27 16:24
    John,

    There really isn’t any information with which to formulate even a guess. What code are you running? What is connected to the I/O and how? Are you drawing power from the BS2p40 on-board regulator and if so, how much?

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    Chris Savage
    Parallax Tech Support
  • John@PUMPKEY.COMJohn@PUMPKEY.COM Posts: 5
    edited 2008-06-27 16:37
    The power supply is external. I have tried to isolate the problem by removing all I can from the circuit. The only thing connected to the BS2P40 are 100K pullup resistors attached to all 32 i/o ports. Here is the program I am using to trouble shoot.
    ' {$STAMP BS2p}
    ' {$PBASIC 2.5}
    main:
    MAINIO
    DIRS =%000000000000000
    AUXIO
    DIRS =%000000000000000
    goto main:

    thank you,
    John
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2008-06-27 16:49
    John,

    While the 100K resistors are not necessary, they wouldn’t cause the problem. And though there is no need to keep setting the direction registers that too would not cause this. My guess is it related to the power supply. No details were provided. What voltage is the external supply and to which pin is it being connected?

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    Chris Savage
    Parallax Tech Support
  • John@PUMPKEY.COMJohn@PUMPKEY.COM Posts: 5
    edited 2008-06-27 17:52
    Ground is on pin4 and pin39, +5 on pin37.
  • allanlane5allanlane5 Posts: 3,815
    edited 2008-06-27 19:40
    What is the "other" end of the 100K resistors tied to? Vdd, I hope?
  • John@PUMPKEY.COMJohn@PUMPKEY.COM Posts: 5
    edited 2008-06-27 19:47
    Yes the resistor banks pull up to the +5Vdd. in parallel with an IC, which I have removed from its socket, to isolate for this issue.
  • allanlane5allanlane5 Posts: 3,815
    edited 2008-06-27 19:57
    Okay but "in parallel with an IC" doesn't sound like "the only thing connected" normally. I mean, for troubleshooting you've pulled the IC, but "normally" the IC would be in there, right? So, what's the IC? Input pins? Output pins? Is there 220 ohm current limiting resistors between them?
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2008-06-27 22:18
    What is your 5V source made up of? Today I saw someone setting up a 3.3V source that output 9V. This was due to a missing capacitor. I have also seen noisy supplies and unregulated supplies cause issues like this.

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    Chris Savage
    Parallax Tech Support
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