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STM32与LM95071通信问题

Other Parts Discussed in Thread: LM95071

TI的工程师:

您好!我用STM32通过SPI口与LM95071通信,一直读不出数据,请问我的SPI口配置是否正确?代码如下:

初始化代码:

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13 | GPIO_Pin_14 | GPIO_Pin_15;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //PB13/14/15复用推挽输出
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);//初始化GPIOB

GPIO_SetBits(GPIOB,GPIO_Pin_13|GPIO_Pin_14|GPIO_Pin_15); //PB13/14/15上拉

SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex; //设置SPI单向或者双向的数据模式:SPI设置为双线双向全双工
SPI_InitStructure.SPI_Mode = SPI_Mode_Master; //设置SPI工作模式:设置为主SPI
SPI_InitStructure.SPI_DataSize = SPI_DataSize_16b; //设置SPI的数据大小:SPI发送接收8位帧结构
SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;//SPI_CPOL_High; //串行同步时钟的空闲状态为高电平
SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge; //串行同步时钟的第二个跳变沿(上升或下降)数据被采样
SPI_InitStructure.SPI_NSS = SPI_NSS_Soft; //NSS信号由硬件(NSS管脚)还是软件(使用SSI位)管理:内部NSS信号有SSI位控制
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256; //定义波特率预分频的值:波特率预分频值为256
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB; //指定数据传输从MSB位还是LSB位开始:数据传输从MSB位开始
SPI_InitStructure.SPI_CRCPolynomial = 7; //CRC值计算的多项式
SPI_Init(SPI2, &SPI_InitStructure); //根据SPI_InitStruct中指定的参数初始化外设SPIx寄存器

SPI_Cmd(SPI2, ENABLE); //使能SPI外设

读数据函数代码:

u16 SPI2_ReadWriteByte16(u16 TxData)
{
u16 retry=0;
while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_BSY) == SET)
{
retry++;
if(retry>200)return 1;
}
SPI_I2S_SendData(SPI2, TxData); //通过外设SPIx发送一个数据
retry=0;
while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_BSY) == SET)
{
retry++;
if(retry>200)return 2;
}
return SPI_I2S_ReceiveData(SPI2); //返回通过SPIx最近接收的数据
}

主函数内读温度:

RxData16=0x0000;
RxData16=SPI2_ReadWriteByte16(RxData16);
printf ("RxData2:%x\r\n",RxData16);