AMIS-30621 Datasheet, PDF (9/43 Pages) AMI SEMICONDUCTOR – LIN Microstepping Motordriver

AMIS-30621 LIN Microstepping Motordriver
Data Sheet
8.4 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 combination of
acceleration index and maximum speed (gray cells).
The accuracy of Acc is derived from the internal oscillator.
Vmax (FS/s) ‘
ACC Index
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
99 136 167 197 213 228 243 273 303 334 364 395 456 546 729 973
Acceleration (Full-step/s²)
49
106
473
218
735
1004
3609
6228
8848
11409
13970
16531
19092
21886
24447
27008
29570
29570
34925
40047
The formula to compute the number of equivalent Full-step
during acceleration phase is:
8.5 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 the table below.
When using command SetPositionShort or
GotoSecurePosition, data is automatically aligned.
Stepping
Position Word: Pos [15 : 0]
Shift
Mode
1/16^th
S B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB
No shift
1/8^th
S B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB 0 1-bit left ↔ x2
1/4^th
S B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB 0
0 2-bit left ↔ x4
Half-stepping S B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB 0
0
0 3-bit left ↔ x8
PositionShort S S S B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB 0
0
0
No shift
SecurePosition S B9 B8 B7 B6 B5 B4 B3 B2 B1 LSB 0
0
0
0
0
No shift
8.5.1 Position Ranges
A position is coded by using the binary two’s complement
format. According to the positioning commands which are
used (see § 9.2.2.11) and to the chosen stepping mode, the
position range will be as shown in the table below.
Command
SetPosition
SetPositionShort
Stepping Mode
Half-stepping
1/4^th micro-stepping
1/8^th micro-stepping
1/16^th micro-stepping
Half-stepping
Position Range
-4096 to +4095
-8192 to +8191
-16384 to +16383
-32768 to +32767
-1024 to +1023
Full Range
8192 half-steps
16384 micro-steps
32768 micro-steps
65536 micro-steps
2048 half-steps
Number
13
14
15
16
11
When using the command SetPosition, although coded
on 16 bits, the position word will have to be shifted on the
left by a certain number of bits, according to the chosen
stepping mode.
AMI Semiconductor - Rev. 1.4
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