Posted on April 11, 2012 at 19:48Hi, I got two different devices with the microcontroler STM32F103RB which I'm trying to comunicate between them using the SPI protocol.
The element A, is the master :
The element B, is the slave :
When I send from A(master) to B(slave) it works fine like that, but it doens't work when I try to send form B to A. I know that B must use the time clock that gives A (SCKL) but I don't know how it should work ?
I couldn't find the same example
Here I attach the example code:
-master (A): SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;
SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;
SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256; //SPI_BaudRatePrescaler_8;
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
SPI_InitStructure.SPI_CRCPolynomial = 7;
SPI_Init(SPI1, &SPI_InitStructure);
/* Enable SPI2 RXNE interrupt */
SPI_ITConfig(SPI1, SPI_IT_RXNE, ENABLE);
/* Enable SPI1 */
SPI_Cmd(SPI1, ENABLE);
main{
...
while(SPI_GetFlagStatus(SPI1, SPI_FLAG_TXE) == RESET);
SPI_SendData(SPI1, '0');
...
}
-slave(B): void init_spi(void){
SPI_InitTypeDef SPI_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
/* Configure and enable SPI1 interrupt -------------------------------------*/
NVIC_InitStructure.NVIC_IRQChannel = SPI1_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_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_2Edge;
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);
/* Enable SPI1 RXNE interrupt */
SPI_I2S_ITConfig(SPI1, SPI_I2S_IT_RXNE, ENABLE);
/* Enable SPI1 */
SPI_Cmd(SPI1, ENABLE);
}
void SPI1_IRQHandler(void)
{ /* Store SPI1 received data */
u8 temp,i;
temp = SPI_I2S_ReceiveData(SPI1);
if(temp==4){
if(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);
SPI_I2S_SendData(SPI1, 'R');
}
