STM32F4_SPI_CR1_DFF
stm32_spi_set_bits(spi, STM32FX_SPI_CR1, STM32F4_SPI_CR1_DFF);
stm32_spi_clr_bits(spi, STM32FX_SPI_CR1, STM32F4_SPI_CR1_DFF);