原子哥，我用了SPI的单向发送模式，但SPI的波形节奏好像有些慢

sore-loser

正确的波形应该是这样的（用双向是正确的）：MODE两种模式下，发送的数据是紧紧跟随的

但用了SPI_Direction_1Line_Tx模式时，波形就慢了：

初始化是这样的：

[mw_shl_code=c,true]void SPI1_Init(void) { GPIO_InitTypeDef GPIO_InitStructure; RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOA|RCC_APB2Periph_SPI1, ENABLE ); GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_7; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOA, &GPIO_InitStructure); GPIO_SetBits(GPIOA,GPIO_Pin_5|GPIO_Pin_7); SPI_InitStructure.SPI_Direction = SPI_Direction_1Line_Tx; SPI_InitStructure.SPI_Mode = SPI_Mode_Master; SPI_InitStructure.SPI_DataSize = SPI_DataSize_16b; SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low; SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge; SPI_InitStructure.SPI_NSS = SPI_NSS_Soft; SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256; SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB; SPI_InitStructure.SPI_CRCPolynomial = 7; SPI_Init(SPI1, &SPI_InitStructure); SPI_Cmd(SPI1, ENABLE); } [/mw_shl_code]

发送函数：

[mw_shl_code=c,true]void SPI1_ReadWriteByte(u16 TxData) { while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET); SPI_I2S_SendData(SPI1, TxData); }[/mw_shl_code]

MODE的操作是这样的：

[mw_shl_code=c,true] MODE=1; SPI1_ReadWriteByte(DC[0]); SPI1_ReadWriteByte(DC[1]); SPI1_ReadWriteByte(DC[2]); SPI1_ReadWriteByte(DC[3]); SPI1_ReadWriteByte(DC[4]); SPI1_ReadWriteByte(DC[5]); while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET){} MODE=0; SPI1_ReadWriteByte(GS[0]); SPI1_ReadWriteByte(GS[1]); SPI1_ReadWriteByte(GS[2]); SPI1_ReadWriteByte(GS[3]); SPI1_ReadWriteByte(GS[4]); SPI1_ReadWriteByte(GS[5]); while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET){} MODE=1; [/mw_shl_code]

之前用的mini板的双向程序是正确的，只不过不去读数据，就时钟线和MOSI两根线。用了单向TX后波形就慢了

sore-loser

回复【2楼】yklstudent:
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恩恩，用的逻辑分析仪测得，示波器太晃了