Have 5V supply to ATmega32 but no voltage across pin 1??

Discussion in 'The Projects Forum' started by kris_maher, Apr 24, 2009.

  1. kris_maher

    Thread Starter Active Member

    Apr 24, 2009
    90
    0
    Hi guys,

    I'm working on a project which is based around ultrasonic transducers.

    I have a 9V battery which I was able to get down to 5V thanks to a voltage regulator whose wire is connected to the VCC pin (10) on my chip.

    All the GND are grounded on the breadboard, pins 11 and 31 are connected firmly to ground

    I checked with Multimeter and there's 5V across VCC as expected, and there's 5V across the RESET pin (pin 9) as expected and 2.5V each for XTAL2/XTAL1 (pins 12 and 13. These are related to the connection of external inverting amp etc).

    I'm using an internal timer. My dilemma is that I've created a timer signal that oscillates at 100Hz sent to PORTB bit 0 (Pin 1). I have a buzzer connected to it along with the other wire of it to GND.

    The buzzer beeps as expected on the development board but when I put the chip over to the breadboard when I check the voltages there's no voltage signal at all on pin 1 - it's only at 250mv and I need 3.3V min across pin 1 to drive the buzzer. When the ATmega32 chip is on the development board, there is a constant 3-4V across pin 1.

    Even something as simple as an LED does not flash when the chip is on the breadboard and wires all connected, even though it does on the development board when connected to pin 1 and the other leg to ground.

    Any ideas on why there's no voltage reaching pin 1 guys?

    Please help, Thanks

    PS: All wires are firmly connected and I checked several times against the datasheet's pin configuration diagram.
     
  2. damjanmi

    New Member

    Apr 23, 2009
    4
    0
    Maybe your breadboard is faulty. Try moving mcu couple of pins.
     
  3. kris_maher

    Thread Starter Active Member

    Apr 24, 2009
    90
    0
    My breadboard is not faulty. It's brand new.
     
  4. StayatHomeElectronics

    Well-Known Member

    Sep 25, 2008
    864
    40
    Does the ATmega32 do anything when it is in the breadboard? Is there any indication that it is booting up at all?
     
  5. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Can you take a clear photo of your bread board and post it here so that we may see your connections? A schematice would be helpful also.

    hgmjr
     
  6. kris_maher

    Thread Starter Active Member

    Apr 24, 2009
    90
    0
    Ahh thanks everyone!

    Actually the problem all along was I didn't set the clock fuses. Setting it to 8MHz made the thing work just right ;)

    Yes I'm somewhat of a newbie at AVR (just started this semester for a uni project). It's nice to learn new things along the way!
     
  7. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    I have been playing with AVR 8-bit micros for a number of years and have really had a lot of fun with the devices.

    Let us know if you have any hardware or software issues that are giving you problems. Hopefully we can assist you in resolving them.

    hgmjr
     
  8. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    A side note;
    If you're trying to use a crystal as a clock source with your uC, a breadboard will likely cause you much grief due to the high parasitic capacitance. Breadboards are great for low-speed analog and digital, but can cause a good deal of trouble when you get up into the MHz ranges.
     
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