STM32F407 SPI NSS

spi1.send(mac, 3); 
spi1.send(buf, 3);

void Spi1::send(uint8_t *data, uint8_t len)
{ 
  uint8_t i;
  while(SPI2->SR & SPI_SR_BSY);                  //Wait transmit all data 
  //while(!(SPI1->SR & SPI_SR_TXE));
  DMA2->LIFCR |= DMA_LIFCR_CTCIF3;               //Clear flag DMA event
  DMA2_Stream3->NDTR = len;                     //Set len tx 
  for(i = 0; i < len; i++)
        {
            txData[i] = *data++;                       //Copy data to buffer
       }     
  DMA2_Stream3->CR |= DMA_SxCR_EN;                //Enable DMA tx */
}

HAL_SPI_Transmit_DMA(&hspi1, mac, 3);
     HAL_SPI_Transmit_DMA(&hspi1, buf, 3);

void Spi1::send(uint8_t *data, uint8_t len)
{ 
 uint8_t i;
 while(SPI2->SR & SPI_SR_BSY);                  //Wait transmit all data 
 while(!(SPI1->SR & SPI_SR_TXE));               //Crutch
 DMA2->LIFCR |= DMA_LIFCR_CTCIF3;               //Clear flag DMA event
 DMA2_Stream3->NDTR = len;                      //Set len tx 
 for(i = 0; i < len; i++)
      {
         txData[i] = *data++;                       //Copy data to buffer
      }  
 DMA2_Stream3->CR |= DMA_SxCR_EN;                 //Enable DMA tx */
}

HAL_SPI_Transmit(&hspi2, buf, 3 , 0xFFFFFFF);
HAL_SPI_Transmit(&hspi2, mac, 3 , 0xFFFFFFF);

HAL_SPI_Transmit(&hspi2, buf, 3 , 0xFFFFFFF);

uint8_t buf[6] = {50, 128, 0 , 0, 0};
while(1)
      { 
        HAL_SPI_Transmit(&hspi2, buf, 2 , 0xFFFFFFF);
        HAL_Delay(20);
       }

uint8_t buf[6] = {50, 127, 0 , 0, 0};
while(1)
      { 
        HAL_SPI_Transmit(&hspi2, buf, 2 , 0xFFFFFFF);
        HAL_Delay(20);
       }