stm32和dsp spi通信问题miso无法拉低

qqmt · 发表于 2017-6-12 11:19:54

本帖最后由 qqmt 于 2017-6-12 11:21 编辑

求各位的大神指点下，现在一块stm32的片子作为从机，dsp的片子作为主机。从机接收正常（mosi空闲低电平），但主机接收的一直是0xff（主机未接从机时miso口就是高电平），用示波器看确实miso一直是高电平就算从机给的数据是0x00也无法将它拉低，请问下是我哪没配置对么，还是电路的问题？[mw_shl_code=cpp,true]//Configure SPI2 pins: SCK and MOSI
      GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12|GPIO_Pin_13|GPIO_Pin_15;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);
      //MISO
      GPIO_InitStructure.GPIO_Pin = GPIO_Pin_14;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);
SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
SPI_InitStructure.SPI_Mode    = SPI_Mode_Slave;
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_Hard;                                        //硬件片选  由主SPI拉低
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_4;
SPI_InitStructure.SPI_FirstBit       = SPI_FirstBit_MSB;
SPI_InitStructure.SPI_CRCPolynomial    = 7;                                                                //大于1就好 <9
SPI_Init(SPI2, &SPI_InitStructure);[/mw_shl_code]