What happens when MCU power up - cortex M4

Discussion in 'Embedded Systems and Microcontrollers' started by Vindhyachal Takniki, Dec 25, 2014.

  1. Vindhyachal Takniki

    Thread Starter Member

    Nov 3, 2014
    1. I want to know what happens when MCU powered up specific to cortex M4.
    2. I have attached one keil program using TM4C123GH6PM. Its basic program to start working.
    3. TM4C123GH6PM has 16Mhz internal OSC

    4. I had read that flash/ram in M4 are arranged in below sequence:

    Flash-> test+lireal , read only data , copy of ram data section
    Ram -> Data section , bss section , heap , stack

    5. According to me the exact sequence is:

    Power up or any reset -> Internal clock 16Mhz init -> All peripheral/system register assigned default values -> bss section assign zero value -> ram data section assigned values from flash -> PC goes to reset handler
    • test.zip
      File size:
      184.2 KB
  2. JWHassler


    Sep 25, 2013
    You must yourself write (or copy) every single byte of the program that is executed at power-up or any other time.

    Your item (5) looks about right.