AMIS-30542 Datasheet, PDF (16/29 Pages) ON Semiconductor – AMIS-30542 Micro-Stepping Motor Driver

AMIS−30542
Change from lower to higher resolution
Iy
DIR
endpos
Iy
DIR
NXT3 ^NXT2
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
PC20070604.6
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
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].
Peak Current
4.75 A
Current Range 3
CUR[ 4:0] = 23 −> 31
2.40 A
Current Range 2
CUR [4:0] = 16 −> 22
1.20 A
615 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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