problem rs232 interfacing from MCU atmega8l to pc

Discussion in 'Embedded Systems and Microcontrollers' started by twinklu7, Oct 15, 2009.

  1. twinklu7

    Thread Starter New Member

    Aug 11, 2009
    I am a newbie ..i am interfacing MCU atmega8l to PC through RS232 ,here i did the loop back test via hyperterminal i didn't get the response from the MCU.
    And before communicating to mcu i did the loop back test to the following for these i got the response
    Start from the cable and work you way over to the PIC. Use hypertem to do a loopback in each of the following steps. I understand that step 1 will pass and step 4 will fail in your case.
    1. Remove the RS232 cable from the Inchworm and short pins 2 and 3 on the cable.
    2. If step 1 passed: Remove the MAX232. Look at the schematic and determine which pins on the MAX232 socket connect to 2 and 3 on the DB9. Short these pins at the MAX232 socket. If this works you know the RS232 signal is getting to the MAX232. If not you have bad solder joints between the DB9 and the MAX232 socket.
    3. If step 2 passed: Replace the MAX232 and remove the PIC. Short the MAX232 pins that go to TX and RX on the PIC at the MAX232 chip. If this works your MAX232 is working.
    and here the 4 th step i tried but i am not able to identify where my communication pbm is?So i need some assitance
    4. If step 3 passed: Short the TX and RX pins on the PIC. If this fails you have bad solder joints between the MAX232 and the PIC.
    Please would anybody try to help out..
  2. KitCarlson


    Sep 27, 2009
    If step 1 passes loop back works on the PC.
    You never indicate what happens for steps 2 and 3.

    What are you doing in software? What is your baud rate? What are you using for the oscillator, and the frequency. Does the mega8 seem to function, (blink a led) if you program that test?