# keil v5 STM32F4 - Cannot access memory

I am using an STM32F407VGT board with an STLINK V2 programmer in keil IDE. I have downloaded to the board a very simple code:

#include "stm32f407xx.h"
#include <stdint.h>

int main(void)
{
RCC_TypeDef *pRCC;
GPIO_TypeDef *pGPIO;
pRCC = RCC;
pGPIO = GPIOA;

pRCC->APB2ENR |= (1 << 0);
pGPIO->PUPDR = 0x11;
return 0;
}


The problem is that when I try to enter to Debug Session, I cant use breakpoints or see the memory, the command window shows "cannot access memory". I have done the needed debug setup, even I have tried changing the parameters but I just cant´t access the memory on debug, but i do not have problems loading my code. I have also tried on Eclipse/OpenOCD and I also can download the code to the board, but it has the same issue with debugging.

This is my board

and this is how keil looks.

• replace your return 0; with a while(1);. You don't want to return from main in an embedded situation. – Colin Feb 13 '18 at 8:32
• You need to write a Configuration file for you controller that tells what area(Address) of the Memory is what! You need to added that when debugging. I don't remember how you do but I have written one somewhere. Will write more when I get near Home PC – MaNyYaCk Feb 13 '18 at 13:09

• I used STM32F4DISCOVERY board that employing STM32F407VGT6 micro-controller. I think I also changed Debug > Connect & Reset Options value other than Normal. – Pana Feb 13 '18 at 6:30