我请教下STM32的SPI配置，如果没有片选信号线时的配置方法

丝带机

我现在遇到一个问题，采用STM32的硬件SPI，但是没接片选信号线，想问下，我现在想使用SPI2，该怎样配置呢？下面是我自己的配置代码，但发现始终SPI没工作。

[mw_shl_code=c,true]RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI2, ENABLE); RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);////SCK RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE);////MOSI/MISO GPIO /**********配置SPI 口的IO口功能************/ GPIO_PinAFConfig(GPIOC,GPIO_PinSource3,GPIO_AF_SPI2); //Port C Pin 3 is SPI2 MOSI GPIO_PinAFConfig(GPIOC,GPIO_PinSource2,GPIO_AF_SPI2); //Port C Pin 2 is SPI2 MISO GPIO_PinAFConfig(GPIOB,GPIO_PinSource10,GPIO_AF_SPI2); //Port B Pin 10 is SPI2 SCK /* Configure SPI MISO */ GPIO_InitStructure_SPI2_MISO.GPIO_Pin = GPIO_Pin_2; GPIO_InitStructure_SPI2_MISO.GPIO_Speed = GPIO_Speed_50MHz; GPIO_InitStructure_SPI2_MISO.GPIO_Mode = GPIO_Mode_OUT; GPIO_InitStructure_SPI2_MISO.GPIO_OType = GPIO_OType_PP; GPIO_InitStructure_SPI2_MISO.GPIO_PuPd = GPIO_PuPd_NOPULL; GPIO_Init(GPIOC, &GPIO_InitStructure_SPI2_MISO); /* Configure SPI MOSI */ GPIO_InitStructure_SPI2_MOSI.GPIO_Pin = GPIO_Pin_3; GPIO_InitStructure_SPI2_MOSI.GPIO_Speed = GPIO_Speed_50MHz; GPIO_InitStructure_SPI2_MOSI.GPIO_Mode = GPIO_Mode_OUT; GPIO_InitStructure_SPI2_MOSI.GPIO_OType = GPIO_OType_PP; GPIO_InitStructure_SPI2_MOSI.GPIO_PuPd = GPIO_PuPd_NOPULL; GPIO_Init(GPIOC, &GPIO_InitStructure_SPI2_MOSI); /* Configure SPI SCK */ GPIO_InitStructure_SPI2_SCK.GPIO_Pin = GPIO_Pin_10; GPIO_InitStructure_SPI2_SCK.GPIO_Speed = GPIO_Speed_50MHz; GPIO_InitStructure_SPI2_SCK.GPIO_Mode = GPIO_Mode_OUT; GPIO_InitStructure_SPI2_SCK.GPIO_OType = GPIO_OType_PP; GPIO_InitStructure_SPI2_SCK.GPIO_PuPd = GPIO_PuPd_NOPULL; GPIO_Init(GPIOB, &GPIO_InitStructure_SPI2_SCK); /* Configure SPI*/ SPI_InitStruct.SPI_Direction = SPI_Direction_2Lines_FullDuplex; SPI_InitStruct.SPI_Mode = SPI_Mode_Master;// ((uint16_t)0x0004) SPI_InitStruct.SPI_DataSize = SPI_DataSize_8b; SPI_InitStruct.SPI_CPOL = SPI_CPOL_Low; SPI_InitStruct.SPI_CPHA = SPI_CPHA_1Edge; //SPI_CPHA_1Edge SPI_InitStruct.SPI_NSS = SPI_NSS_Soft; SPI_InitStruct.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_8; //SPI_BaudRatePrescaler_8 //设置波特率预分频值是8 SPI_InitStruct.SPI_FirstBit = SPI_FirstBit_MSB; SPI_InitStruct.SPI_CRCPolynomial = 7; //SPI2->CR2 |= (1<<2); //SSOE Slave Select is output only (NO MULTIMASTER)使能SSN SPI_Init(SPI2,&SPI_InitStruct); SPI_Cmd( SPI2,ENABLE);[/mw_shl_code]

SPI读写函数：

[mw_shl_code=c,true]void BSP_ReadWriteByte(uint8_t* txBuff, uint8_t* rxBuff, uint16_t length) { volatile uint16_t i; //BSP_CLEAR_SS; USE_SPIx->DR = txBuff[0]; for(i=1;i<length;i++){ while(!(USE_SPIx->SR & SPI_I2S_FLAG_TXE)); USE_SPIx->DR = txBuff; while(!(USE_SPIx->SR & SPI_I2S_FLAG_RXNE)); rxBuff[i-1]=USE_SPIx->DR; } if(length == 1){ while(!(USE_SPIx->SR & SPI_I2S_FLAG_TXE)); while(!(USE_SPIx->SR & SPI_I2S_FLAG_RXNE)); while(USE_SPIx->SR & SPI_I2S_FLAG_BSY); rxBuff[length-1]=USE_SPIx->DR; }else{ while(USE_SPIx->SR & SPI_I2S_FLAG_BSY); rxBuff[length-1]=USE_SPIx->DR; } //BSP_SET_SS; } [/mw_shl_code]

八度空间

1、SPI_InitStruct.SPI_NSS = SPI_NSS_Soft;

这句就是配置CS片选管脚的，参数SPI_NSS_Soft表示不用硬件的CS，而是用自定义的IO管脚去控制芯片的CS管脚

2、GPIO_InitStructure_SPI2_SCK.GPIO_Mode = GPIO_Mode_OUT;

你的这个参数模式配置不对，应该是设置成复用推挽输出模式GPIO_Mode_AF