STMicroelectronics Fully integrated stepper motor driver mounting the L6472 in a high power PowerSO package EVAL6472PD EVAL6472PD データシート

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DocID022729 Rev 3

The MARK register contains an absolute position called MARK, in accordance with the 
selected step mode; the stored value unit is equal to the selected step mode (full, half, 
quarter, etc.).

It is in 2's complement format and it ranges from -2

21

 to +2

21

-1. 

The SPEED register contains the current motor speed, expressed in step/tick (format 
unsigned fixed point 0.28).

In order to convert the SPEED value in step/s the following formula can be used: 

where SPEED is the integer number stored in the register and tick is 250 ns.

The available range is from 0 to 15625 step/s with a resolution of 0.015 step/s.

Any attempt to write the register causes the command to be ignored and the 
NOTPERF_CMD flag to rise (see 

).

The ACC register contains the speed profile acceleration expressed in step/tick

2

 (format 

unsigned fixed point 0.40).

In order to convert ACC value in step/s2 the following formula can be used:

where ACC is the integer number stored in the register and tick is 250 ns.

The available range is from 14.55 to 59590 step/s

2

 with a resolution of 14.55 step/s

2

.

When the ACC value is set to 0xFFF the device works in infinite acceleration mode.

Any attempt to write to the register when the motor is running causes the command to be 
ignored and the NOTPERF_CMD flag to rise (see 

The DEC register contains the speed profile deceleration expressed in step/tick

2

 (format 

unsigned fixed point 0.40).

In order to convert the DEC value in step/s2 the following formula can be used:

step s







SPEED 2

28

–



tick

-------------------------------------

=

step s







ACC 2

40

–



tick

2

-----------------------------

=