Atmega32 Microcontroller

Discussion in 'Embedded Systems and Microcontrollers' started by Etronic, Aug 19, 2015.

  1. Etronic

    Thread Starter Active Member

    Oct 7, 2011
    127
    2
    Can you people on here who ever used these atmega chips can tell me. Are all the GND pins 11 and 31 internally connected.
    And if so. Do I still need to GND each pin to the neg rail of my circuit.Or can i just use say pin 11 to GND and not GND pin
    31. and what will happen if all the GND pin are not connected to the Neg rail.
     
    RRITESH KAKKAR likes this.
  2. nerdegutta

    Moderator

    Dec 15, 2009
    2,515
    785
    I do not know if they are internally connected, but, if the engineers that designed the microcontroller made the leg GND, I guess it has a purpose.
     
  3. hexreader

    Active Member

    Apr 16, 2011
    250
    82
    You must connect all ground pins externally, or intermittent operation may result.

    There is no reliable internal connection.
     
  4. ScottWang

    Moderator

    Aug 23, 2012
    4,852
    767
    They are internally connected, I think there are two parts need the big current, the left part is PB0~7 and PD0~6 and the right part is the PA0~7 and PC0~7

    You still need to connect them to ground, it can be increasing the current loop from ground when the PA0~7 and PC0~7, PD7 sink the current from outside.

    The chip may not works properly, because the internal ICs can't get the current loop from ground.
     
  5. Etronic

    Thread Starter Active Member

    Oct 7, 2011
    127
    2
    OK? This is what i needed to know.

    Can i connect all the GNDs together externally. Then just use one wire to connect them all to the Neg rail. Or do i need to tire each GND
    pin separately to the neg rail. Does it make a difference either way they are connected.

    Thanks for your response.
     
  6. Etronic

    Thread Starter Active Member

    Oct 7, 2011
    127
    2
    OK? This is what i needed to know.

    Can i connect all the GNDs together externally. Then just use one wire to connect them all to the Neg rail. Or do i need to tire each GND
    pin separately to the neg rail. Does it make a difference either way they are connected.

    Thanks for your response.
     
  7. ScottWang

    Moderator

    Aug 23, 2012
    4,852
    767
    You can connect two GND to one wire, but the wire should be enough to privide the current for what the uC needed, it must be including the current sink from the external parts or devices.
     
  8. Etronic

    Thread Starter Active Member

    Oct 7, 2011
    127
    2


    What do mean By?.

    It must be including the current sink from the external parts or devices.

    The wire i am use is rate for 600V 3A.
     
  9. ScottWang

    Moderator

    Aug 23, 2012
    4,852
    767
    What I tried to said was that when the port of uC output low then the current of external parts will be sink to the internal MOSFET to GND.

    Assuming that there are two ports output low in the same time, and each bit of port sink 20 mA then the total current is 20 mA *16bits=320mA, Imax=40mA

    About the GND wire, are you use the wire to connect the uC pin or use PCB layout, any wire or the copper foil of PCB can be flows through around 1A then it's OK.
     
  10. Etronic

    Thread Starter Active Member

    Oct 7, 2011
    127
    2
    I'm using one of those 840 ties PCB it looks just like the matching solder less breadboards.
    And using both PCB with wiring, with 24gauge and 30gauge wire that's rated for 3amps.
    My total circuit will draw 50mA max when all parts are continuously on. And that it coming from the two LEDs which are 20mA each but only one of them will be on all the time.
    The power status LED. The signal LED only comes on when it detects a voltage signal.

    the circuit design.Now I transfer to the matching PCB That looks just like the solder less board.
    then i just match all the wires and parts to that PCB. The total current of the circuit is 50mA the only parts on the that will draw most of current are two LEDs at 20mA which is 40mA But one of the LEDs will not continuously be on all the time
     
  11. ScottWang

    Moderator

    Aug 23, 2012
    4,852
    767
    Could you take some photos for wires and PCB?
     
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