AMIS-30624 Datasheet, PDF (12/56 Pages) AMI SEMICONDUCTOR – I2C Microstepping Motordriver

AMIS-30624
12.4 Acceleration and Deceleration
Sixteen possible values can be programmed for Acc (acceleration and deceleration between V_min and V_max). Table 9 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 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
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 is programmed in the command SetPosition and is given as a number of (micro)steps. According to the chosen
stepping mode, the position word must be aligned as described in Table 10. When using command GotoSecurePosition, data is
automatically aligned.
Table 10: 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
Rev. 4 | Page 12 of 56 | www.onsemi.com