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SPI Master-Slave Interface STM32

Question asked by D3K on Feb 4, 2017
Latest reply on Feb 4, 2017 by Clive One

Hi All, I am trying to interface two STM32 discovery boards one as master and one as slave using the following code snippets. Sometimes the data seems to arrive correctly at other times it is corrupted. I just call the mySPI_SendData and mySPI_GetData functions from the main loop. Any helps with this issue? Thanks.

 

void mySPI_SendData(uint8_t adress, uint16_t data){

 

GPIO_ResetBits(GPIOA, GPIO_Pin_15);

 

while(!SPI_I2S_GetFlagStatus(SPI3, SPI_I2S_FLAG_TXE));
SPI_I2S_SendData(SPI3, data);
while(!SPI_I2S_GetFlagStatus(SPI3, SPI_I2S_FLAG_RXNE));
SPI_I2S_ReceiveData(SPI3);
 
GPIO_SetBits(GPIOA, GPIO_Pin_15);

}

 

uint16_t mySPI_GetData(uint16_t adress){

while ((SPI_NSS_bit == 1)|(SPI_NSS_bit == -1))
{
SPI_NSS_bit = GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_15);
}

 

while(!SPI_I2S_GetFlagStatus(SPI3, SPI_I2S_FLAG_RXNE));
SPI_I2S_ReceiveData(SPI3); //Clear RXNE bit
while(!SPI_I2S_GetFlagStatus(SPI3, SPI_I2S_FLAG_TXE));
SPI_I2S_SendData(SPI3, 0x0000); //Dummy byte to generate clock

 

return SPI_I2S_ReceiveData(SPI3);
}

 

void mySPI_Init(void){

RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI3, ENABLE);

SPI_InitTypeDef SPI_InitTypeDefStruct;


SPI_InitTypeDefStruct.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
SPI_InitTypeDefStruct.SPI_Mode = SPI_Mode_Slave;
SPI_InitTypeDefStruct.SPI_DataSize = SPI_DataSize_16b;
SPI_InitTypeDefStruct.SPI_CPOL = SPI_CPOL_High;
SPI_InitTypeDefStruct.SPI_CPHA = SPI_CPHA_1Edge;
SPI_InitTypeDefStruct.SPI_NSS = SPI_NSS_Soft;
SPI_InitTypeDefStruct.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256;
SPI_InitTypeDefStruct.SPI_FirstBit = SPI_FirstBit_MSB;

SPI_Init(SPI3, &SPI_InitTypeDefStruct);


RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_GPIOE , ENABLE);

GPIO_InitTypeDef GPIO_InitTypeDefStruct;

/*-------- Configuring SCK PC10, MISO PC11, MOSI PC12 --------*/

GPIO_InitTypeDefStruct.GPIO_Pin = GPIO_Pin_10 | GPIO_Pin_11 | GPIO_Pin_12;
GPIO_InitTypeDefStruct.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitTypeDefStruct.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitTypeDefStruct.GPIO_OType = GPIO_OType_PP;
GPIO_InitTypeDefStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOC, &GPIO_InitTypeDefStruct);

GPIO_InitTypeDefStruct.GPIO_Pin = GPIO_Pin_15;
GPIO_InitTypeDefStruct.GPIO_Mode = GPIO_Mode_IN;
GPIO_InitTypeDefStruct.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitTypeDefStruct.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_InitTypeDefStruct.GPIO_OType = GPIO_OType_PP;
GPIO_Init(GPIOA, &GPIO_InitTypeDefStruct);

GPIO_PinAFConfig(GPIOC, GPIO_PinSource10, GPIO_AF_SPI3);
GPIO_PinAFConfig(GPIOC, GPIO_PinSource11, GPIO_AF_SPI3);
GPIO_PinAFConfig(GPIOC, GPIO_PinSource12, GPIO_AF_SPI3);
//GPIO_PinAFConfig(GPIOA, GPIO_PinSource15, GPIO_AF_SPI3);

//GPIO_SetBits(GPIOA, GPIO_Pin_15);


SPI_Cmd(SPI3, ENABLE);
}

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