AMIS-30623 LIN Microstepping Motordriver
Data Sheet
13.4 Acceleration and Deceleration
Sixteen possible values can be programmed for Acc (acceleration and deceleration between Vmin and Vmax). Table 10 provides the
obtainable values in full-step/s². One observes restrictions for some combination of acceleration index and maximum speed (gray cells).
The accuracy of Acc is derived from the internal oscillator.
Table 10: Acceleration and Deceleration Selection Table
99 136 167 197 213 228 243 273 303 334 364 395 456 546 729 973
Vmax (FS/s) →
↓ Acc index
Acceleration (Full-step/s²)
Hex
0
1
Dec
0
1
49
106
473
735
218
2
2
1004
3
3
3609
4
4
6228
5
5
8848
6
7
8
9
A
B
C
D
E
F
6
7
8
9
10
11
12
13
14
15
11409
13970
16531
19092
21886
24447
27008
29570
34925
40047
29570
The formula to compute the number of equivalent full-step during acceleration phase is:
Vmax 2 − Vmin2
Nstep =
2× Acc
13.5 Positioning
The position programmed in commands SetPositionand SetPositionShortis given as a number of (micro)steps. According to
the chosen stepping mode, the position words must be aligned as described in Table 11. When using command SetPositionShort
or GotoSecurePosition, data is automatically aligned.
Table 11: Position Word Alignment
Stepping mode
1/16th
Position word: Pos[15:0]
B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB
B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB
B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB
B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB
B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB
B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB
Shift
No shift
1-bit left ⇔ ×2
2-bit left ⇔ ×4
3-bit left ⇔ ×8
S
S
S
S
1/8th
0
0
0
1/4th
Half-stepping
0
0
0
PositionShort
SecurePosition
Notes
S
S
S
S
0
0
0
0
0
0
No shift
No shift
0
0
(1) LSB: Least Significant Bit
(2) S: Sign bit
AMI Semiconductor – June 2006, Rev 3.0
14
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