STM32 SPI master routine

#include "stm32f10x.h"

/*RCC clock configuration*/

void RCC_config(void)

{ 

ErrorStatus HSEStartUpStatus;

/* RCC registers are set to default configuration */

RCC_DeInit();

/* Turn on external high speed clock */

RCC_HSEConfig(RCC_HSE_ON);

/* Wait for the external high-speed clock to stabilize*/

HSEStartUpStatus = RCC_WaitForHSEStartUp();

if(HSEStartUpStatus == SUCCESS) 

{ 

/* Set HCLK = SYSCLK */

RCC_HCLKConfig(RCC_SYSCLK_Div1);

/* Set PCLK2 = HCLK */

RCC_PCLK2Config(RCC_HCLK_Div1);

/* Set PCLK1 = HCLK / 2 */

RCC_PCLK1Config(RCC_HCLK_Div2);

// /* Set FLASH code delay */

// FLASH_SetLatency(FLASH_Latency_2);

// /* Enable prefetch cache */

// FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);

/* Set the PLL clock source to HSE multiplier 9 72MHz */

RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9);

/* Enable PLL */

RCC_PLLCmd(ENABLE);

/* Wait for PLL to stabilize */

while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET);

/* Set PLL as system clock source */

RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);

/* Wait for the system clock source to switch to PLL */

while(RCC_GetSYSCLKSource() != 0x08);

}

}

/* GPIO configuration */

void GPIO_config(void)

{

GPIO_InitTypeDef GPIO_InitStructure;

/* Clock configuration */

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

/* MISO is configured as a floating input */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

GPIO_Init(GPIOA, &GPIO_InitStructure);

/* SCK and MOSI are configured as multiplexed push-pull outputs */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_7;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

GPIO_Init(GPIOA, &GPIO_InitStructure);

/* NSS is configured as push-pull output */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;

GPIO_Init(GPIOA, &GPIO_InitStructure);

}

/* SPI configuration */

void SPI_config(void)

{

SPI_InitTypeDef SPI_InitStructure;

/* Clock configuration */

RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO | RCC_APB2Periph_SPI1, ENABLE); 

/* Configure SPI mode */

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);

/* Open SPI1 */

SPI_Cmd(SPI1, ENABLE);

}

/* Millisecond delay function */

void delay_ms(uint16_t time)

{    

uint16_t i = 0;  

while(time--)

{

i = 12000;

while(i--);    

}

}

/* SPI sends a data */

uint8_t SPI_SendByte(uint8_t data)

{

while(SPI_I2S_GetFlagStatus(SPI1,SPI_I2S_FLAG_TXE) == RESET);

SPI_I2S_SendData(SPI1, data);

while(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);

return SPI_I2S_ReceiveData(SPI1);

}

/* Main function */

int main(void)

{

volatile uint8_t i = 0, j;

/*RCC clock configuration*/

RCC_config();

/* GPIO configuration */

GPIO_config(); 

/* SPI configuration */

SPI_config(); 

while(1)

{

GPIO_ResetBits(GPIOA, GPIO_Pin_4);

j = SPI_SendByte(i++);

GPIO_SetBits(GPIOA, GPIO_Pin_4);

/* 1 second delay */

delay_ms(500);

}

}