How do you configure SPI in CC2540.
I read the user guide. You set UxCSR.MODE to 0.
But I don't understand how to make UxCSR.MODE 0.
Do you do it in the firmware?
Yes, you do it in the firmware - talke a look at any HAL driver module, say _hal_uart_dma.c, and look how the USART registers are all directly set to specific values (as well as the DMA registers, etc.)