EVAL6470H Datasheet, PDF (43/70 Pages) STMicroelectronics – dSPIN fully integrated microstepping motor driver with motion engine and SPI

L6470
9.1.7
9.1.8
Programming manual
where DEC is the integer number stored in the register and tick is 250 ns.
The available range is from 14.55 to 59590 step/s2 with a resolution of 14.55 step/s2.
When the device is working in infinite acceleration mode, this value is ignored.
Any attempt to write the register when the motor is running causes the command to be
ignored and the NOTPERF_CMD flag to rise (see Section 9.1.22).
MAX_SPEED
The MAX_SPEED register contains the speed profile maximum speed expressed in
step/tick (format unsigned fixed point 0.18).
In order to convert it in step/s, the following formula can be used:
Equation 7
[step/s] = ^M------^A----^X-----^_---^S----^P----^E----^E----^D------^â‹------²---^–---¹--⁸-
tick
where MAX_SPEED is the integer number stored in the register and tick is 250 ns.
The available range is from 15.25 to 15610 step/s with a resolution of 15.25 step/s.
MIN_SPEED
The MIN_SPEED register contains the following parameters:
Table 11. MIN_SPEED register
Bit 12 Bit 11 Bit 10 Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
LSPD_OPT
MIN_SPEED
9.1.9
The MIN_SPEED parameter contains the speed profile minimum speed. Its value is
expressed in step/tick and to convert it in step/s, the following formula can be used:
Equation 8
[step/s] = ^M------^I--^N-----^_---^S----^P----^E----^E----^D------^â‹------²---^–---²--⁴-
tick
where MIN_SPEED is the integer number stored in the register and tick is the ramp 250 ns.
The available range is from 0 to 976.3 step/s with a resolution of 0.238 step/s.
When the LSPD_OPT bit is set high, the low speed optimization feature is enabled and the
MIN_SPEED value indicates the speed threshold below which the compensation works. In
this case the minimum speed of the speed profile is set to zero.
An attempt to write the register when the motor is running causes the NOTPERF_CMD flag
to rise.
FS_SPD
The FS_SPD register contains the threshold speed. When the actual speed exceeds this
value, the step mode is automatically switched to full-step two-phase on. Its value is
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