DRV8461SPWPR datasheet(26/117 Pages) TI

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Table 7-13. Automatic Microstepping Interpolation Level

RES_AUTO

Interpolation

00b (default)

1/256

01b

1/128

10b

1/64

11b

1/32

Table 7-14 show both coil currents and the smooth transition between half-step mode and automatic

microstepping mode by writing 1b and 0b respectively to the EN_AUTO bit. Notice that the step frequency

is same in both half-step and 1/256 automatic microstepping modes.

Table 7-14. Transition between half-step and automatic microstepping

Transition from half-step mode to 1/256 automatic microstepping

Transition from 1/256 automatic microstepping to half-step mode

STEP

Motor Angle

Figure 7-8. Automatic Microstepping with Changing STEP Frequency

As shown in Figure 7-8, the interpolation is done based on the time between the two previous step pulses. The

previous interval time is interpolated to equal divisions, depending on the RES_AUTO bit setting.

When input step frequency reduces from previous interval (shown in segment '1'), the motor holds its position till

the next STEP active edge occurs. Device will go to standstill power saving mode if the EN_STSL bit is 1b, and

the next active edge does not come before tSTSL_DLY expires. Standstill power saving mode is exited on the next

STEP active edge.

When step frequency increases from previous interval (shown in segment '2'), the motor angle smoothly auto-

corrects when the next STEP active edge comes, and the indexer moves to a position corresponding to the

STEP input. In segment '3', the motor angle is incremented at a faster rate, corresponding to the step frequency

of segment '2'.

DRV8461

SLOSE98 – DECEMBER 2022

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DRV8461SPWPR 데이터시트(PDF) 26 Page - Texas Instruments