AMIS-30532_15 Datasheet, PDF (16/29 Pages) ON Semiconductor – Micro-Stepping Motor Driver

AMIS−30532
Change from lower to higher resolution
Iy
DIR
endpos
Iy
DIR
NXT2
NXT3
NXT1
NXT4
startpos
Ix
Ix
Change from higher to lower resolution
Iy
endpos
DIR
NXT1
Iy
startpos
DIR
NXT2
Ix _NXT3
Ix
Halfstep
1/4^th step
1/8^th step
Figure 12. NXT−Step Mode Synchronization
Halfstep
Left: Change from lower to higher resolution. The left−hand side depicts the ending half−step position during which a new
step mode resolution was programmed. The right−hand side diagram shows the effect of subsequent NXT commands on the
micro−step position.
Right: Change from higher to lower resolution. The left−hand side depicts the ending micro−step position during which a new
step mode resolution was programmed. The right−hand side diagram shows the effect of subsequent NXT commands on the
half−step position.
Note: It is advised to reduce the micro−stepping resolution only at micro−step positions that overlap with desired micro−step
positions of the new resolution.
Programmable Peak−Current
The amplitude of the current waveform in the motor coils
(coil peak current = I_max) is adjusted by means of an SPI
parameter ”CUR[4:0]” (see Table 14 SPI Control Parameter
Peak Current
3.02 A
Overview). Whenever this parameter is changed, the
coil−currents will be updated immediately at the next PWM
period. Figure 13 presents the Peak−Current and Current
Ratings in conjunction to the Current setting CUR[4:0].
Current Range 3
CUR[ 4:0] = 23 −> 31
1.26 A
Current Range 2
CUR [4:0] = 16 −> 22
654 mA
328 mA
Current Range 1
CUR[4:0] = 9 −> 15
Current Range 0
CUR[4:0] = 0 −> 8
0
8
15
22
31 CUR[4:0]
Figure 13. Programmable Peak−Current Overview
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