[ARM] STM32F4 interfacing with SPI Issue

[hirenvaja]

here is my code

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#define sbi(port,bit)       port |= (1<<bit)
#define cbi(port,bit)       port &= ~(1<<bit)
#define cb(port,bit)        port & (1<<bit)
 
void clock_setup();
void spi_master_setup();
void spi_tx(unsigned char tx);
void gpio_init();
void spi_enable();
 
void clock_setup()
{
        sbi(RCC->APB2ENR,12);       //enable clock for SPI1
        sbi(RCC->AHB1ENR,0);        //enable clock for GPIOA
}
 
void spi_master_setup()
{
        cbi(SPI1->CR1,15); //spi 2 line unidirection full duplex
        sbi(SPI1->CR1,2);    //spi1 in master mode
        cbi(SPI1->CR1,11); //SPI1 in 8 bit data format
        sbi(SPI1->CR1,1);    //CPOL=1 clock polarity 1 when idle
        sbi(SPI1->CR1,0);    //CPHA=1 second clock transition is the first data capture edge
        cbi(SPI1->CR1,9);    //NSS software slave management---------------
        SPI1->CR1 &= ~((1<<3) | (1<<4) | (1<<5));   //000 for prescaler fpclk/2
        cbi(SPI1->CR1,7);    //MSB first
}
 
void gpio_init()
{
        GPIOA->MODER |= ((1<<11) | (1<<13) | (1<<15));  //set A5,A6,A7 as alternate function mode
        GPIOA->OTYPER &= ~((1<<5) | (1<<6) | (1<<7));       //output type pushpull
        GPIOA->OSPEEDR &= ~((1<<10) | (1<<11) | (1<<12) | (1<<13) | (1<<14) | (1<<15)); //output speed
        GPIOA->AFR[0] |= ((1<<20) | (1<<22)); //select AF5 for SPI_SCK
        GPIOA->AFR[0] |= ((1<<24) | (1<<26));   //select AF5 for SPI_MISO
        GPIOA->AFR[0] |= ((1<<28) | (1<<30));   //select AF5 for SPI_MISO
        
        sbi(GPIOA->MODER,0);    //set 0th bit to set GPIOA_0 as output mode
        cbi(GPIOA->OTYPER,0);   //Push-pull
        GPIOA->OSPEEDR &= ~((1<<0) | (1<<1));   //low speed
        sbi(GPIOA->ODR,0);
}
 
void spi_enable()
{
        sbi(SPI1->CR1,6);
}
 
void spi_tx(unsigned char tx)
{
        cbi(GPIOA->ODR,0);
        tx=SPI1->DR;
        while(!(cb(SPI1->SR,1)));
        SPI1->DR = tx;
        sbi(GPIOA->ODR,0);
}
 
void delayf(unsigned int x);
int main()
{
        unsigned char tx=0;
        clock_setup();
        spi_master_setup();
        gpio_init();
        spi_enable();
        while(1)
        {
                tx++;
                spi_tx(tx);
                delayf(10);
        }
}
 
void delayf(unsigned int x)
{
        unsigned int i,j;
        for(i=0;i<x;i++)
        {
                for(j=0;j<1000;j++);
        }
}

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[KlausST]

Hi,

No error description?
No "hello", no "please".
What do you expect from us?

Klaus

 

[hirenvaja]

Hi,

No error description?
No "hello", no "please".
What do you expect from us?

Klaus

actually i have just checked this code on keilv5 stlink debugger .problem is that once data is transmitted through spi register then transmit buffer flag is set in status register and it is not cleared after so it stucks in while loop

please suggest me solutions

 

[Aussie Susan]

binary 0 is not a very good value to use for a test - it is hard to distinguish this from "nothing at all" on the MOSI line (although you should still get the clock signal etc.). Try using something like 0xaa or 0x55 which is easy to see on a scope.
I think you have things a bit mixed up in the 'spi_tx' function. By the look of it you are reading FROM the DR register (i.e. getting the last received value) and then waiting for the SPI peripheral to not be busy - well it is idle at that point as you have not told it to do anything so of course you will be waiting for ever.
Only after the while statement do you tell it to send your character.
Try the more traditional order of 1) wait for the peripheral to be idle (optional but I think this is useful); 2) send the value; 3) wait for the exchange to be complete; 4) read the received value.
For an example (that I know does not use quite the same initialisation structures) look at **broken link removed** and the 'SPI1_send' function.
Susan