AMIS-30621 Datasheet, PDF (12/59 Pages) AMI SEMICONDUCTOR – LIN Microstepping Motordriver

AMIS−30621
Acceleration and Deceleration
Sixteen possible values can be programmed for Acc
(acceleration and deceleration between Vmin and Vmax).
The table below provides the obtainable values in
full−step/s². One observes restrictions for some
combinations of acceleration index and maximum speed
(gray cells).
The accuracy of Acc is derived from the internal
oscillator.
Table 9. ACCELERATION AND DECELERATION SELECTION TABLE
Vmax (FS/s) → 99 136 167 197 213 228 243 273 303 334 364 395 456 546 729 973
↓ Acc Index
Hex
Dec
Acceleration (Full−step/s²)
0
0
49
106
473
1
1
218
735
2
2
1004
3
3
3609
4
4
6228
5
5
8848
6
6
11409
7
7
13970
8
8
16531
9
9
19092
A
10
21886
B
11
24447
C
12
27008
D
13
29570
E
14
29570
34925
F
15
40047
The formula to compute the number of equivalent
full−steps during acceleration phase is:
V max ² * V min ²
Nstep +
2 Acc
Positioning
The position programmed in commands SetPosition
and SetPositionShort is given as a number of
(micro−)steps. According to the chosen stepping mode, the
position words must be aligned as described in the table
below. When using command SetPositionShort or
GotoSecurePosition, data is automatically aligned.
Table 10. POSITION WORD ALIGNMENT
Stepping Mode
Position Word: Pos[15:0]
1/16^th
1/8^th
1/4^th
S B14 B13 B12 B11 B10 B9 B8 B7 B6 B5
S B13 B12 B11 B10 B9 B8 B7 B6 B5 B4
S B12 B11 B10 B9 B8 B7 B6 B5 B4 B3
Half−stepping
S B11 B10 B9 B8 B7 B6 B5 B4 B3 B2
B4 B3 B2 B1 LSB
B3 B2 B1 LSB 0
B2 B1 LSB 0 0
B1 LSB 0 0 0
Shift
No shift
1−bit left ⇔ ×2
2−bit left ⇔ ×4
3−bit left ⇔ ×8
PositionShort
SecurePosition
S S S B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB 0 0 0
S B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB 0 0 0 0 0
No Shift
No shift
NOTES: LSB: Least Significant Bit
S: Sign bit, two’s complement
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