AMIS-30522 Datasheet, PDF (12/29 Pages) AMI SEMICONDUCTOR – Micro-stepping Motor Driver

AMIS-30522
8.3.4. Translator Position
The translator position can be read in Table 32. This is a 7-bit number equivalent to the 1/32^th micro-step from Error! Reference
source not found.. The translator position is updated immediately following a NXT trigger.
NXT
Update
Translator Position
Update
Translator Position
Figure 10: Translator Position Timing Diagram
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8.3.5. Synchronization of Step Mode and NXT Input
When step mode is re-programmed to another resolution (Table 15), then this is put in effect immediately upon the first arriving
“NXT” input. If the micro-stepping resolution is increased (Figure 11), then the coil currents will be regulated to the nearest micro-
step, according to the fixed grid of the increased resolution. If however the micro-stepping resolution is decreased, then it is
possible to introduce an offset (or phase shift) in the micro-step translator table.
If the step resolution is decreased at a translator table position that is shared both by the old and new resolution setting, then the
offset is zero and micro-stepping is proceeds according to the translator table.
If the translator position is not shared both by the old and new resolution setting, then the micro-stepping proceeds with an offset
relative to the translator table (See Figure 10 right hand side).
Change from lower to higher resolution
Iy
DIR
endpos
Iy
DIR
NXT2
NXT3
NXT1
NXT4
startpos
Change from higher to lower resolution
Iy
endpos
DIR
Iy
DIR
NXT1
startpos
NXT2
Ix
Ix
Ix _NXT3
Ix
Halfstep
1/4^th step
1/8^th step
Halfstep
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Figure 11: NXT-Step Mode Synchronization
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.
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