pub type CPHA_W<'a, const O: u8> = BitWriter<'a, u32, SPI_TCR_SPEC, CPHA_A, O>;
Field cpha writer - SPI Clock/Data Phase Control
cpha
struct CPHA_W<'a, const O: u8> { /* private fields */ }
Phase 0 (Leading edge for sample data)
Phase 1 (Leading edge for setup data)