STM32F4 SPI Configuration SPI_Init causes assert_failed loop

Question

I'm trying to configure SPI to work with a ST7565 GLCD library which is given here. For now, I'm trying to use SPI1 to achieve this. When the init function -which is given below- is called in main(), it causes the program to loop in assert_failed function.

void init_SPI1(void){

    GPIO_InitTypeDef GPIO_InitStruct;
    SPI_InitTypeDef SPI_InitStruct;

    // enable clock for used IO pins
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

    /* configure pins used by SPI1
     * PA5 = SCK
     * PA6 = MISO
     * PA7 = MOSI
     */
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_7 | GPIO_Pin_6 | GPIO_Pin_5;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_Init(GPIOA, &GPIO_InitStruct);

    // connect SPI1 pins to SPI alternate function
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_SPI1);
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_SPI1);
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_SPI1);

    // enable clock for used IO pins
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE, ENABLE);

    /* Configure the chip select pin
       in this case we will use PE7 */
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_7;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_OUT;
    GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_Init(GPIOE, &GPIO_InitStruct);

    GPIOE->BSRRL |= GPIO_Pin_7; // set PE7 high

    // enable peripheral clock
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);

    /* configure SPI1 in Mode 0 
     * CPOL = 0 --> clock is low when idle
     * CPHA = 0 --> data is sampled at the first edge
     */
    SPI_InitStruct.SPI_Direction = SPI_Direction_1Line_Tx; // set to full duplex mode, seperate MOSI and MISO lines
    SPI_InitStruct.SPI_Mode = SPI_Mode_Master;     // transmit in master mode, NSS pin has to be always high
    SPI_InitStruct.SPI_DataSize = SPI_DataSize_8b; // one packet of data is 8 bits wide
    SPI_InitStruct.SPI_CPOL = SPI_CPOL_Low;        // clock is low when idle
    SPI_InitStruct.SPI_CPHA = SPI_CPHA_1Edge;      // data sampled at first edge
    SPI_InitStruct.SPI_NSS = SPI_NSS_Soft; // set the NSS management to internal and pull internal NSS high
    SPI_InitStruct.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_16; // SPI frequency is APB2 frequency / 4
    SPI_InitStruct.SPI_FirstBit = SPI_FirstBit_MSB;// data is transmitted MSB first

    SPI_Init(SPI1, &SPI_InitStruct); 
    SPI_Cmd(SPI1, ENABLE); // enable SPI1
}

I've noticed that program goes in infinite loop inside assert_failed function when it reaches SPI_Init() line:

SPI_Init(SPI1, &SPI_InitStruct);

The assert_failed function ( Default in Firmware Library) is below:

void assert_failed(uint8_t* file, uint32_t line)
{ 
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */

  /* Infinite loop */
  while (1)
  {

  }
}

I don't know what does it supposed to mean that it loops in assert_failed function. Is it a problem to do with the SPI configuration. I need guidance to understand the problem and generate a solution. Any help will be greately appreciated. Thanks in advance.

EDIT: I've checked inside of the SPI_Init function in stm32f4xx_spi.c

void SPI_Init(SPI_TypeDef* SPIx, SPI_InitTypeDef* SPI_InitStruct)
{
  uint16_t tmpreg = 0;

  /* check the parameters */
  assert_param(IS_SPI_ALL_PERIPH(SPIx));

  /* Check the SPI parameters */
  assert_param(IS_SPI_DIRECTION_MODE(SPI_InitStruct->SPI_Direction));
  assert_param(IS_SPI_MODE(SPI_InitStruct->SPI_Mode));
  assert_param(IS_SPI_DATASIZE(SPI_InitStruct->SPI_DataSize));
  assert_param(IS_SPI_CPOL(SPI_InitStruct->SPI_CPOL));
  assert_param(IS_SPI_CPHA(SPI_InitStruct->SPI_CPHA));
  assert_param(IS_SPI_NSS(SPI_InitStruct->SPI_NSS));
  assert_param(IS_SPI_BAUDRATE_PRESCALER(SPI_InitStruct->SPI_BaudRatePrescaler));
  assert_param(IS_SPI_FIRST_BIT(SPI_InitStruct->SPI_FirstBit));
  assert_param(IS_SPI_CRC_POLYNOMIAL(SPI_InitStruct->SPI_CRCPolynomial));

Since the library is locked, I cant get to type anything inside to debug in Live Watch. (I'm using IAR EWARM)

unwind · Answer 1 · 2014-03-03T12:02:50.157

It loops in assert() because the assert failed, so the loop is there to stop further execution.

Just step up on your stack so that you can see which assert in the peripheral library it was that failed. The library does pretty extensive validation of its parameters, so probably something is wrong in one of your calls.

UPDATE It seems you never initialize the CRCPolynomial field, but it's asserted upon. I suggest adding a call to SPI_StructInit() to make sure your init struct is sanely initialized, before you start setting it up according to your application's wishes.

STM32F4 SPI Configuration SPI_Init causes assert_failed loop

1 Answers1