Unable to communicate with DAC using SPI - stm32

Question

I am trying to communicate with my DAC using SPI from my STM32L4 controller. I basically want to test if the SPI lines are working fine.i.e if I am able to transmit data and receive to and from the DAC respectively. I have configured the DAC pins as follows -
static void MX_GPIO_Init(void)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOC_CLK_ENABLE();
__HAL_RCC_GPIOH_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
__HAL_RCC_GPIOB_CLK_ENABLE();
GPIO_InitStruct.Pin = RST_Pin|M_Z_Pin|TC_SB_Pin|LDAC_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
GPIO_InitStruct.Pin = PD_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
GPIO_InitStruct.Pin = SPI3_Chip_Select_DAC_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/*Configure GPIO pins : READY_Pin LDAC_Pin BUSY_Pin */
GPIO_InitStruct.Pin = READY_Pin|BUSY_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
HAL_GPIO_WritePin(RST_GPIO_Port,RST_Pin,GPIO_PIN_SET);
HAL_GPIO_WritePin(M_Z_GPIO_Port,M_Z_Pin,GPIO_PIN_RESET);
HAL_GPIO_WritePin(TC_SB_GPIO_Port,TC_SB_Pin,GPIO_PIN_SET);
HAL_GPIO_WritePin(LDAC_GPIO_Port,LDAC_Pin,GPIO_PIN_RESET);
HAL_GPIO_WritePin(PD_GPIO_Port,PD_Pin,GPIO_PIN_RESET);
HAL_GPIO_WritePin(SPI3_Chip_Select_DAC_GPIO_Port,SPI3_Chip_Select_DAC_Pin,GPIO_PIN_SET);
}
I want to read the contents of the status register, to which I have to send 0xC0 on the SPI line (as specified in the datasheet). In return, the DAC returns the contents of the status register. So, I have written the following code for it -
SPI_HandleTypeDef hspi1;
SPI_HandleTypeDef hspi2;
SPI_HandleTypeDef hspi3;
TIM_HandleTypeDef htim3;
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USB_OTG_FS_USB_Init(void);
static void MX_SPI1_Init(void);
static void MX_SPI2_Init(void);
static void MX_SPI3_Init(void);
static void MX_TIM3_Init(void);
uint8_t received_data[3],Data_to_send[3];
int main(void)
{
HAL_Init();
/* Configure the system clock */
SystemClock_Config();
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_SPI1_Init();
MX_SPI2_Init();
MX_SPI3_Init();
MX_TIM3_Init();
while(1)
{
HAL_GPIO_WritePin(SPI3_Chip_Select_DAC_GPIO_Port,SPI3_Chip_Select_DAC_Pin,GPIO_PIN_RESET);
HAL_Delay(1);
Data_for_try[0]=0xC0;
HAL_SPI_TransmitReceive(&hspi3,Data_to_send,received_data,3,100);
HAL_Delay(1);
HAL_GPIO_WritePin(SPI3_Chip_Select_DAC_GPIO_Port,SPI3_Chip_Select_DAC_Pin,GPIO_PIN_SET);
}
}
But I am unable to get any data back as an acknowledgement from the DAC. I have checked that the SPI_CLOCK and the SPI_MOSI pin are getting the signals using an oscilloscope. Is there any way to check if the DAC is working fine?

Answer 1

Thanks for the support, but I was able to figure out the problem. I had to change the SPI settings as follows -
static void MX_SPI3_Init(void)
{
/* SPI3 parameter configuration*/
hspi3.Instance = SPI3;
hspi3.Init.Mode = SPI_MODE_MASTER;
hspi3.Init.Direction = SPI_DIRECTION_2LINES;
hspi3.Init.DataSize = SPI_DATASIZE_8BIT;
hspi3.Init.CLKPolarity = SPI_POLARITY_LOW;
hspi3.Init.CLKPhase = SPI_PHASE_1EDGE;
hspi3.Init.NSS = SPI_NSS_SOFT;
hspi3.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_2;
hspi3.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi3.Init.TIMode = SPI_TIMODE_DISABLE;
hspi3.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi3.Init.CRCPolynomial = 7;
hspi3.Init.CRCLength = SPI_CRC_LENGTH_DATASIZE;
hspi3.Init.NSSPMode = SPI_NSS_PULSE_ENABLE;
if (HAL_SPI_Init(&hspi3) != HAL_OK)
{
Error_Handler();
}
}
The hspi3.Init.DataSize was initialised to SPI_DATASIZE_4BIT instead of SPI_DATASIZE_8BIT which was the problem.