L6472 datasheet(22/69 Pages) STMICROELECTRONICS

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Functional description

L6472

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Doc ID 022729 Rev 1

6.4.1

Automatic full-step mode

When motor speed is greater than a programmable full-step speed threshold, the L6472

switches automatically to full-step mode (see Figure 7); the driving mode returns to

microstepping when motor speed decreases below the full-step speed threshold. The full-

step speed threshold is set through the FS_SPD register (see Section 9.1.9).

Figure 7.

Automatic full-step switching

6.5

Absolute position counter

An internal 22-bit register (ABS_POS) keeps track of the motor motion according to the

selected step mode; the stored value unit is equal to the selected step mode (full, half,

quarter, etc.). The position range is from -221 to +221-1 (µ) steps (see Section 9.1.1).

6.6

Programmable speed profiles

The user can easily program a customized speed profile, independently defining

acceleration, deceleration, maximum and minimum speed values through the ACC, DEC,

MAX_SPEED and MIN_SPEED registers respectively (see Section 9.1.5, 9.1.6, 9.1.7 and

9.1.8).

When a command is sent to the device, the integrated logic generates the microstep

frequency profile that performs a motor motion compliant to speed profile boundaries.

All acceleration parameters are expressed in step/tick2 and all speed parameters are

expressed in step/tick; the unit of measurement does not depend on selected step mode.

Acceleration and deceleration parameters range from 2-40 to (212-2)•2-40 step/tick2

(equivalent to 14.55 to 59590 step/s2).

Minimum speed parameter ranges from 0 to (212-1)•2-24 step/tick (equivalent to 0 to 976.3

step/s).

Maximum speed parameter ranges from 2-18 to (210-1)• 2-18 step/tick (equivalent to 15.25 to

15610 step/s).

L6472 数据表(PDF) 22 Page - STMicroelectronics