AMIS-30623 LIN Microstepping Motordriver
13.4 Acceleration and Deceleration
Data Sheet
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
↓
Acc index
Hex
Dec
0
0
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
A
10
B
11
C
12
D
13
E
14
F
15
136
167
197
213
228
243
273
303
334
364
395
456
546
729
973
Acceleration (Full-step/s²)
49
218
1004
3609
6228
8848
11409
13970
16531
19092
21886
24447
27008
29570
34925
40047
106
473
735
14785
29570
The formula to compute the number of equivalent full-step during acceleration phase is:
Vmax
2
−
Vmin
2
Nstep
=
2
×
Acc
13.5 Positioning
The position programmed in commands
and
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
or
data is automatically aligned.
Table 11: Position Word Alignment
Stepping mode
1/16
th
1/8
th
1/4
th
Half-stepping
PositionShort
SecurePosition
Notes
(1) LSB: Least Significant Bit
(2) S: Sign bit
S
S
S
S
S
S
Position word:
Pos[15:0]
B14 B13 B12 B11 B10 B9 B8 B7 B6 B5
B13 B12 B11 B10 B9 B8 B7 B6 B5 B4
B12 B11 B10 B9 B8 B7 B6 B5 B4 B3
B11 B10 B9 B8 B7 B6 B5 B4 B3 B2
S
S
B9 B8 B7 B6 B5 B4 B3 B2
B9 B8 B7 B6 B5 B4 B3 B2 B1
LSB
B4 B3 B2 B1
LSB
B3 B2 B1
LSB
0
0
B2 B1
LSB
0
B1
LSB
0
0
0
0
0
B1
LSB
0
0
0
0
0
0
Shift
No shift
1-bit left
⇔ ×2
2-bit left
⇔ ×4
3-bit left
⇔ ×8
No shift
No shift
AMI Semiconductor
– June 2006, Rev 3.0
14
www.amis.com
AMI [ AMI SEMICONDUCTOR ]
