AMIS-30623 Datasheet, PDF (12/65 Pages) AMI SEMICONDUCTOR – LIN Microstepping Motordriver

AMIS-30623
12.4 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
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
F
15
29570
34925
40047
The formula to compute the number of equivalent full-step during acceleration phase is:
Nstep = ^{Vmax 2 − Vmin 2}
2 × Acc
12.5 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 Table 11. When using command SetPositionShort
or GotoSecurePosition, data is automatically aligned.
Table 11: Position Word Alignment
Stepping Mode
1/16^th
1/8^th
1/4^th
Position Word: Pos[15:0]
S B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB
S B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB 0
S B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB 0 0
Half-stepping
S B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB 0 0 0
PositionShort
S S S B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB 0 0 0
SecurePosition
S B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB 0 0 0 0 0
Notes:
(1) LSB: Least Significant Bit
(2) S: Sign bit
Shift
No shift
1-bit left ⇔ ×2
2-bit left ⇔ ×4
3-bit left ⇔ ×8
No shift
No shift
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