STM32的SPI查询方式传输测试

环境：

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.