STM32的SPI查询方式传输测试

主机:WIN7

开发环境:MDK4.23

MCU:STM32F103CBT6

说明:

软件设置NSS脚,利用查询方式传输

源代码:

初始化代码:

//关闭SPI
SPI_Cmd(SPI1,DISABLE);
//初始化SPI接口的SSN脚以及NTRX的RST脚
NtrxCtrlInit();
//初始化SPI时钟	
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1 | RCC_APB2Periph_GPIOA,ENABLE);
//配置SPI1引脚:SCK, MISO and MOSI
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP ;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz ;
GPIO_Init( GPIOA, &GPIO_InitStructure );
// SPI1配置
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波特率分频设置:4M
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_8 ;
//SPI设置成LSB模式
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_LSB ;
SPI_InitStructure.SPI_CRCPolynomial = 7 ;
SPI_Init( SPI1, &SPI_InitStructure ) ;
//启动SPI
SPI_Cmd(SPI1,ENABLE);

发送代码:

//SPI发送一个字节
static uint8 SPI_SendByte(uint8 Data)
{
	// Loop while DR register in not emplty
	while( SPI_I2S_GetFlagStatus( SPI1, SPI_I2S_FLAG_TXE ) == RESET ) ;

	// Send byte through the SPI1 peripheral
	SPI_I2S_SendData( SPI1, Data ) ;

	// Wait to receive a byte
	while( SPI_I2S_GetFlagStatus( SPI1, SPI_I2S_FLAG_RXNE ) == RESET ) ;

	// Return the byte read from the SPI bus
	return SPI_I2S_ReceiveData( SPI1 ) ;
}

接收代码:

//SPI读取一个字节
void SPI_ReadBytes( uint8 Addr, NtrxBufferPtr Buffer, uint8 Len )
{
	if( ( Len > 0x80 ) || ( Len == 0 ) )
		Len = 1 ;
	SPI_SendByte( Len ) ;
	SPI_SendByte( Addr ) ;
	while( Len-- )
    {
    	*Buffer = SPI_SendByte( 0xFF ) ;
		Buffer ++ ;
	}
}

NSS脚电平设置:

//SSN脚拉低,开始发送数据
void NtrxSSN_Lo( void )
{
	GPIO_ResetBits( NTRX_SSN_PORT, NTRX_SSN_PIN ) ;
}

//SSN脚置高,结束发送数据
void NtrxSSN_Hi( void )
{
	GPIO_SetBits( NTRX_SSN_PORT, NTRX_SSN_PIN ) ;
}

示例代码:

uint8 NtrxReadSingleSPI( uint8 Addr )
{
	NtrxBufferType r ;
	NtrxSSN_Lo() ;
	SPI_ReadBytes( Addr, &r, 1 ) ;
	NtrxSSN_Hi() ;
	return r ;
}

输出:

黄线为NSS脚电平,蓝线为CLK电平.