AMIS-30622_13 Datasheet, PDF (13/50 Pages) ON Semiconductor – I2C Micro-Stepping Motor Driver

AMIS−30622
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
O 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
14785
27008
D
13
29570
E
14
F
15
29570
34925
40047
The formula to compute the number of equivalent
full−steps during acceleration phase is:
Nstep
+
Vmax²
2
* Vmin²
Acc
Positioning
The position programmed in command SetPosition
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
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
SecurePosition S B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB 0 0 0 0 0
NOTES: LSB: Least Significant Bit
S: Sign bit
Shift
No shift
1−bit left ⇔ ×2
2−bit left ⇔ ×4
3−bit left ⇔ ×8
No shift
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