CKE = opposite of CPHA
CKP 0 0 1 1 Clock Polarity
CKE 0 1 0 1 Clock Edge
Idle Low Idle Low Idle High Idle High
Change L->H Change H->L Change H->L Change L->H
Read H->L Read L->H Read L->H Read H->L
CKP: Clock Polarity Select bit (CKP == CPOL)
1 = Idle state for clock is a high level; active state is a low level
0 = Idle state for clock is a low level; active state is a high level
CKE: Clock Edge Select bit (CKE == !CPHA)
1 = Serial output data changes on transition from active clock state to idle clock state
0 = Serial output data changes on transition from idle clock state to active clock state
