Posted on June 08, 2017 at 15:04Dear Community,
I want to send and receive SPI data using the SPI-Irq handler of a STM32F407 device. Using a low speed SPI everything worked so far but now I need to speed thinks up and I noticed that receiving works mostly not and I don’t know why. I’ve checked the slave signal (see attached Image: MOSI: blue; MISO:yellow ; CLK:green; CS:pink) to make sure there is data available for receiving and I’ve also checked the MISO pin that indeed receives zero if connected to ground and 1’s if connected to Vdd. Since I have 8 bit and 16bit devices wired together to the same bus I’ve to stick to the 8bit transmission. In this case I've always receive 255.
I think the problem is a timing issue and I would be glad if some could point me to the right direction.
IRQ Handler
void SPIx_IRQHANDLER(void)
{
// SPI in Transmitter mode
if (SPI_I2S_GetITStatus(SPIx, SPI_I2S_IT_TXE) == SET)
{
SPI_I2S_ITConfig(SPIx, SPI_I2S_IT_TXE, DISABLE);
SPI_I2S_SendData(SPIx, aTxBuffer);
Send = false;
}
// SPI in Receiver mode
if (SPI_I2S_GetITStatus(SPIx, SPI_I2S_IT_RXNE) == SET)
{
// SPI_I2S_ITConfig(SPIx, SPI_I2S_IT_RXNE, DISABLE);
aRxBuffer = SPI_I2S_ReceiveData(SPIx);
}
}
Call
unsigned char Send_a_Byte_and_receive(unsigned char TheByte) {
Send = true;
aTxBuffer = TheByte;
// Enable the Tx and Rx buffer empty interrupt
SPI_I2S_ITConfig(SPIx, SPI_I2S_IT_RXNE, ENABLE);
SPI_I2S_ITConfig(SPIx, SPI_I2S_IT_TXE, ENABLE);
while(Send) {}
return aRxBuffer;
}
void ReadData16LSM6DS3(unsigned char address, unsigned char * data) {
LSM6DS3_CS_L();
address = address + (1<<7);
Send_a_Byte_and_receive(address);
WaitSomeTime_GAP_short();
(*data) = Send_a_Byte_and_receive((*data));
WaitSomeTime_GAP_short();
WaitSomeTime_GAP_short();
LSM6DS3_CS_H();
WaitSomeTime_GAP_short();
WaitSomeTime_GAP_short();
}
