Double align is enabled by configuring MTR_STARTUP to 01b. Single align is not reliable when the initial position of the rotor is 180^o out of phase with the applied phase pattern. In this case, it is possible to have start-up failures using single align. In order to improve the reliabilty of align based start-up, the MCF8315A provides the option of double align start-up. In double align start-up, MCF8315A uses a phase pattern for the second align that is 90^o ahead of the first align phase pattern. In double align, relevant parameters like align time, current limit, ramp rate are the same as in the case of single align - two different phase patterns are applied in succession with the same parameters to ensure that the motor will be aligned to a known position irrespective of initial rotor position.