I tried SPI program using register but i did not get any output in KEIL Debugging DR register . The DR register fill 0x00FF . But i send 0xA

[DMuru]

#include "stm32f4xx.h"

#include "stm32f4xx_gpio.h"

#include "stm32f4xx_rcc.h"

#include "stm32f4xx_spi.h"

void Gpio_Init(void)

{

RCC->AHB1ENR = 1<<0; //Enable GPIOA

RCC->APB2ENR = 1<<12; //Enable SPI1

GPIOA->MODER |= 1<<11; //PA5 AF Function

GPIOA->MODER |= 1<<13; //PA6 AF Function

GPIOA->MODER |= 1<<15; //PA7 AF Function

GPIOA->PUPDR |= 0;

GPIOA->OSPEEDR |= 1<<10; //PA5 High Speed

GPIOA->OSPEEDR |= 1<<12; //PA6 High Speed

GPIOA->OSPEEDR |= 1<<14; //PA7 High Speed

GPIOA->AFR[0] |= 5<<20; //PA5

 GPIOA->AFR[0] |= 5<<24; //PA6

 GPIOA->AFR[0] |= 5<<28; //PA7

GPIOA->MODER |= 1<<8;

GPIOA->PUPDR |= 1<<8;

GPIOA->OSPEEDR |= 1<<8;

GPIOA->OTYPER |= 0;

}

void Spi_Init(void)

{

SPI1->CR1 = 1<<0; //CPHA is 1

SPI1->CR1 |= 1<<1; //CPOL is 1

SPI1->CR1 |= 3<<8; // Software mode SSM and SSI bit is set

SPI1->CR1 |= 1<<2; // MSTR bit is set

SPI1->CR1 |= 1<<6; //SPE bit is set

}

int Spi_tx(unsigned char data)

{

GPIOA->BSRRH = GPIO_Pin_4;

SPI1->DR = data; 

while(!(SPI1->SR & SPI_SR_TXE));

while(!(SPI1->SR & SPI_SR_RXNE));

GPIOA->BSRRL = GPIO_Pin_4;

return SPI1->DR;

}

int main()

{

Gpio_Init();

Spi_Init();

while(1)

{

Spi_tx(0xA);

for (int i = 0; i < 1000000; i++) {}; 

}

}