STM32F4 multiple SPI_I2S_GetFlagStatus crashes the program - c

Question

I'm trying to implement a simple http server on my stm32F411RE nucleo board from here, but of course I've run into some problems - so far, I managed to narrow the current one to the fact, that after about 20 calls to
SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE); My program crashes. By crash, I mean goes to the Infinite Loop defined in the startup file, reason being "Program received signal SIGINT, Interrupt."
My spi is initialised like that:
void SPI1_Init(void){
GPIO_InitTypeDef GPIO_InitStructure;
/* Enable SPI1 and GPIOA clocks */
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
//SCK, MISO, MOSI
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_DOWN;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_Init(GPIOA, &GPIO_InitStructure);
//CS
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_DOWN;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);
//CS down
GPIO_SetBits(GPIOA, GPIO_Pin_2);
SPI_InitTypeDef SPI_InitStructure;
/* SPI1 configuration */
SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;
SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;
SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_4;
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
SPI_InitStructure.SPI_CRCPolynomial = 7;
SPI_Init(SPI1, &SPI_InitStructure);
/* Enable SPI1 */
SPI_Cmd(SPI1, ENABLE);
}
after the initialization, I do this:
for(tmpCnt = 0; tmpCnt < 100; tmpCnt++){
SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE);
}
and it crashes after about 20 iterations. I am using the standard peripheral library, and System Workbench with all stock settings of compiler and everything else. At the moment nothing is connected to the SPI pins, could that be the problem?
calling
(SPI1->SR) instead of SPI_I2S_GetFlagStatus
has the same effect so I guess that the problem lies withing reading the register. Why could that be? I'm really stuck at the moment, so any help would be appreciated.
EDIT:
Ok, it turns out that I missed a bit of code that seems to cause this behaviour - before the SPi1->SR calls, I also had this function called:
__STATIC_INLINE uint32_t SysTick_Config(uint32_t ticks)
{
if ((ticks - 1) > SysTick_LOAD_RELOAD_Msk) return (1); /* Reload value impossible */
SysTick->LOAD = ticks - 1; /* set reload register */
NVIC_SetPriority (SysTick_IRQn, (1<<__NVIC_PRIO_BITS) - 1); /* set Priority for Systick Interrupt */
SysTick->VAL = 0; /* Load the SysTick Counter Value */
SysTick->CTRL = SysTick_CTRL_CLKSOURCE_Msk |
SysTick_CTRL_TICKINT_Msk |
SysTick_CTRL_ENABLE_Msk; /* Enable SysTick IRQ and SysTick Timer */
return (0); /* Function successful */
}
why does it break the SPI1->SR access? could there be anything else wrong? My main function:
int main(void)
{
int tmpCnt = 0;
int rev = 0;
//uint16_t writedat = 22;
RCC_Init();
SPI1_Init();
//SysTick_Config(1000);
for(tmpCnt = 0; tmpCnt < 50; tmpCnt++){
SPI1->SR ;
}
enc28j60Init((unsigned char *)enc28j60_MAC);
//simple_server();
rev = enc28j60getrev();
return rev;
}
RCC_Init does not seem to change anything in the behaviour of the SPI1->SR.
As before, any advice would be welcome.