Posted on August 18, 2012 at 00:19I am trying to receive data over full duplex SPI but STM32 does not line up clock and data if I configure in SPI_CPHA_2Edge. However if I configure in SPI_CPHA_1Edge, everything works fine. My slave however sends data in 2Edge. Does anybody have a workaround on this?
void configure_spi(void)
{
//Init GPIO structure
GPIO_InitTypeDef GPIO_InitStructure;
//Init SPI structure
SPI_InitTypeDef SPI_InitStructure;
//Enable SPI clocks
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1,ENABLE);
RCC_PCLK2Config(RCC_HCLK_Div1); //DEFAULT WAS Div2
/* Enable GPIO clocks */
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
//Set GPIOs
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
//GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4 | GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7;
//GPIO_Init(GPIOA, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4; //SS
GPIO_Init(GPIOA, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; //CLK
GPIO_Init(GPIOA, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6; //MISO
GPIO_Init(GPIOA, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7; //MOSI
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* Connect SPI pins to AF5 */
GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_SPI1); //CLK
GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_SPI1); //MOSI
GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_SPI1); //MISO
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_Hard;
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
SPI_InitStructure.SPI_CRCPolynomial = 7;
//SPI_BaudRatePrescaler_8 = 6.7MHz
//SPI_BaudRatePrescaler_4 = 13.xMHz
//SPI_BaudRatePrescaler_2 = 26.8MHz
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_8;
//SPI1- for CLK, DATA, CS(DIR)
SPI_Init(SPI1,&SPI_InitStructure);
//SPI_TIModeCmd(SPI1, ENABLE);
//SPI_I2S_ITConfig(SPI1, SPI_I2S_IT_RXNE, ENABLE);
SPI_SSOutputCmd(SPI1,ENABLE);
SPI_Cmd(SPI1,ENABLE);
}
uint8_t mip_Send_Receive_Byte(uint8_t byte)
{
/*!< Loop while DR register in not emplty */
while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);
/*!< Send byte through the SPI1 peripheral */
SPI_I2S_SendData(SPI1, byte);
/*!< Wait to receive a byte */
while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);
/*!< Return the byte read from the SPI bus */
return SPI_I2S_ReceiveData(SPI1);
}
