Posted on June 20, 2016 at 23:16Hi
I'm struggeling with this problem. I have very simple (two threads) system, that wait for characters from usart. Everything work ok untill I turn on debug session. Then after a while it breaks it with known communicat ''Cannot access target. Shutting down debug session''
I recive characters using interrupts:
void USART1_IRQHandler (void)
{
if(USART1->ISR & USART_ISR_RXNE) {
msgBuffor[msgWritePtr++] = USART1->RDR;
if (msgWritePtr > MESSAGE_BUF_SIZE) {
msgWritePtr = 0;
}
}
}
Initialisation precedure:
void USART1_init(void)
{
RCC->APB2ENR |= RCC_APB2ENR_USART1EN;
RCC->CFGR3 &= ~RCC_CFGR3_USART1SW;
RCC->CFGR3 |= RCC_CFGR3_USART1SW_0;
gpio_pin_cfg(TX_PORT, TX_PIN, GPIO_AF7_PP_50MHz);
gpio_pin_cfg(RX_PORT, RX_PIN, GPIO_AF7_PP_50MHz);
USART1->BRR = SystemCoreClock/115200UL;
USART1->CR1 |= USART_CR1_TE | USART_CR1_RE | USART_CR1_RXNEIE;
USART1->CR1 |= USART_CR1_UE;
NVIC_EnableIRQ( USART1_IRQn );
}
My findings so far:
- when no characters are received - problem does NOT appear,
- when interrupts are blocked obvieusly problem does NOT appear,
- it is not power issiue - checked with an oscilloscope
- CMSIS doesn't stuck in any fault handler procedure
- when run in normal mode both threads works properly (checked with LEDs)
- when debug session is stopped threads go further normaly
Any good idea is welcome
