AnsweredAssumed Answered

"no target connected" in ST Link V2 stm32f4 discovery board and can not reset

Question asked by malmir.sahar on Jul 10, 2014
Latest reply on Aug 6, 2014 by Amel N
I have stm32f4 discovery board, first I could program the board but now It does not work. all jumpers are fine and I'm trying to run a sample program such as LED toggle. I checked the GPIO configuration and I just configure PA.4 for toggling. and this is my simple code:
GPIO_InitTypeDef  GPIO_InitStructure;
int main(void)
 RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
  while (1)
          GPIOA->BSRRL =GPIO_Pin_4;
              GPIOA->BSRRH =GPIO_Pin_4;
 then I tried to reset the board with pulling  BOOT0 high. for this purpose,I connected BOOT0 pin to 3v pin. but It does not work yet. I'm working with Keil uvision 4 and It seems that keil can not recognize the ST Link,there is an error in options for target->Debug->ST Link Debugger ->setting : no ST Link detected.
what should I do? please help me