STM32的SPI查询方式传输测试

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:

[cpp]view plaincopy

1.//关闭SPI

2.SPI_Cmd(SPI1,DISABLE);

3.//初始化SPI接口的SSN脚以及NTRX的RST脚

4.NtrxCtrlInit();

5.//初始化SPI时钟

6.RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1 | RCC_APB2Periph_GPIOA,EN

ABLE);

7.//配置SPI1引脚:SCK, MISO and MOSI

8.GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7;

9.GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP ;

10.GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz ;

11.GPIO_Init( GPIOA, &GPIO_InitStructure );

12.// SPI1配置

13.SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex ;

14.SPI_InitStructure.SPI_Mode = SPI_Mode_Master ;

15.SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b ;

16.SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low ;

17.SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge ;

18.SPI_InitStructure.SPI_NSS = SPI_NSS_Soft ;

19.//SPI波特率分频设置:4M

20.SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_8 ;

21.//SPI设置成LSB模式

22.SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_LSB ;

23.SPI_InitStructure.SPI_CRCPolynomial = 7 ;

24.SPI_Init( SPI1, &SPI_InitStructure ) ;

25.//启动SPI

26.SPI_Cmd(SPI1,ENABLE);

发送代码:

[cpp]view plaincopy

1.//SPI发送一个字节

2.static uint8 SPI_SendByte(uint8 Data)

3.{

4.// Loop while DR register in not emplty

5.while( SPI_I2S_GetFlagStatus( SPI1, SPI_I2S_FLAG_TXE ) == RESET

) ;

6.

7.// Send byte through the SPI1 peripheral

8. SPI_I2S_SendData( SPI1, Data ) ;

9.

10.// Wait to receive a byte

11.while( SPI_I2S_GetFlagStatus( SPI1, SPI_I2S_FLAG_RXNE ) == RESET

) ;

12.

13.// Return the byte read from the SPI bus

14.return SPI_I2S_ReceiveData( SPI1 ) ;

15.}

接收代码:

[cpp]view plaincopy

1.//SPI读取一个字节

2.void SPI_ReadBytes( uint8 Addr, NtrxBufferPtr Buffer, uint8 Len )

3.{

4.if( ( Len > 0x80 ) || ( Len == 0 ) )

5. Len = 1 ;

6. SPI_SendByte( Len ) ;

7. SPI_SendByte( Addr ) ;

8.while( Len-- )

9. {

10. *Buffer = SPI_SendByte( 0xFF ) ;

11. Buffer ++ ;

12. }

13.}

NSS脚电平设置:

[cpp]view plaincopy

1.//SSN脚拉低,开始发送数据

2.void NtrxSSN_Lo( void )

3.{

4. GPIO_ResetBits( NTRX_SSN_PORT, NTRX_SSN_PIN ) ;

5.}

6.

7.//SSN脚置高,结束发送数据

8.void NtrxSSN_Hi( void )

9.{

10. GPIO_SetBits( NTRX_SSN_PORT, NTRX_SSN_PIN ) ;

11.}

示例代码:

[cpp]view plaincopy

1.uint8 NtrxReadSingleSPI( uint8 Addr )

2.{

3. NtrxBufferType r ;

4. NtrxSSN_Lo() ;

5. SPI_ReadBytes( Addr, &r, 1 ) ;

6. NtrxSSN_Hi() ;

7.return r ;

8.}

输出:

黄线为NSS脚电平,蓝线为CLK电平.