Posted on April 22, 2015 at 04:41
I'm trying to setup a STM32F429 as a SPI slave. I have another device transmitting SPI data as a master, and it looks good on the scope + logic analyzer. The STM32F4 never seems to raise the RXNE flag. Any thoughts?
SPI Config function:
void SPI_Slave_Config(){
GPIO_InitTypeDef GPIO_InitStructure;
SPI_InitTypeDef SPI_InitStruct;
/* Enable clocks */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
/* Connect SPI1 pins to AF */
GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_SPI1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_SPI1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_SPI1);
/* Configure pins for SPI1-PinPack1 PA4-NSS, PA5-SCK, PA6-MISO, PA7-MOSI */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7 | GPIO_Pin_6 | GPIO_Pin_5;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;
GPIO_Init(GPIOA, &GPIO_InitStructure);
SPI_I2S_DeInit(SPI1);
SPI_InitStruct.SPI_Direction = SPI_Direction_2Lines_FullDuplex; //seperate MOSI and MISO lines
SPI_InitStruct.SPI_Mode = SPI_Mode_Slave; // slave mode
SPI_InitStruct.SPI_DataSize = SPI_DataSize_8b; // one packet of data is 8 bits wide
SPI_InitStruct.SPI_CPOL = SPI_CPOL_High; // clock is high when idle
SPI_InitStruct.SPI_CPHA = SPI_CPHA_1Edge; // data sampled at first edge
SPI_InitStruct.SPI_NSS = SPI_NSS_Soft; // set the NSS management to internal
SPI_InitStruct.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_4; // not important for Slave?
SPI_InitStruct.SPI_FirstBit = SPI_FirstBit_MSB;// data is transmitted MSB first
SPI_Init(SPI1, &SPI_InitStruct);
SPI_Cmd(SPI1, ENABLE); // enable SPI1
SPI_NSSInternalSoftwareConfig(SPI1, SPI_NSSInternalSoft_Set); // Set the software NSS
}
Main function:
int main(void)
{
int i;
int SPIrx;
/* Configures LEDs */
STM_EVAL_LEDInit(LED3);
STM_EVAL_LEDOn(LED3);
STM_EVAL_LEDInit(LED4);
SPI_Slave_Config();
while(1){
if (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == SET){
STM_EVAL_LEDOn(LED4); // Application never reaches here!
SPIrx = SPI1->DR;
}
if (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == SET){
SPI1->DR = 0xAA; // Load dummy data into SPI TX buffer
}
}
}
#spi-slave
