Stepper Stall Detect (SSD)MPC5606S Microcontroller Reference Manual, Rev. 71178 Freescale Semiconductor36.5.3 SSD startupThe SSD block takes care of smooth transitions between the different steps to avoid current glitches whenthe coil driven by the block (sine or cosine) changes. Single-cycle glitches in the coil drive current atstartup of the SSD flow can be avoided in the following way:• Program the STEP bits reflecting the current position of the SM prior to the SSD flow with theSDCPU bit still cleared.• After programming the STEP bits enable the analog block by setting the SDCPU bit.36.6 Application informationThis is additional information intended for use by the customer.36.6.1 Current flow examplesFigure 36-12 below shows the current flow for a complete sequence of the STEP bits forcounter-clockwise movement including the recirculation time:Figure 36-12. Full step sequence for counter-clockwise movementDifferent Examples of the current flow in the SM coils for different settings of the control bits are givenin Figure 36-13 to Figure 36-16 below:Figure 36-13 below shows the recirculation at the beginning of STEP = 0. The cosine coil is driven in thedirection P M and the sine coil is recirculated against VDDM.0 1 2 30Imax+_ Imax0Imax+_ ImaxSINE COILCURRENTCOSINE COILCURRENTRecirculation
