DRV8711 Datasheet, PDF (12/34 Pages) Texas Instruments – STEPPER MOTOR CONTROLLER IC

DRV8711
SLVSC40 – JUNE 2013
www.ti.com
Table 3 shows the relative current and step directions for full-step through 1/8-step operation. Higher
microstepping resolutions follow the same pattern. The AOUT current is the sine of the electrical angle; BOUT
current is the cosine of the electrical angle.
The reset state is 45°. This state is entered at power-up or application of RESETn. This is shown in the table
below by cells shaded in yellow.
FULL STEP
1/2 STEP
1
1
2
3
2
4
5
3
6
7
4
8
Table 3. Step Directions
1/4 STEP
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1/8 STEP
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
AOUT CURRENT BOUT CURRENT
(% FULL-SCALE) (% FULL-SCALE)
0
20
38
56
71
83
92
98
100
98
92
83
71
56
38
20
0
-20
-38
-56
-71
-83
-92
-98
-100
-98
-92
-83
-71
-56
-38
-20
100
98
92
83
71
56
38
20
0
-20
-38
-56
-71
-83
-92
-98
-100
-98
-92
-83
-71
-56
-38
-20
0
20
38
56
71
83
92
98
ELECTRICAL
ANGLE
(DEGREES)
0
11.325
22.5
33.75
45 (home state)
56.25
67.5
78.75
90
101.25
112.5
123.75
135
146.25
157.5
168.75
180
191.25
202.5
213.75
225
236.25
247.5
258.75
270
281.25
292.5
303.75
315
326.25
337.5
348.75
At each rising edge of the STEP input, or each time a '1' is written to the RSTEP bit in the CTRL register, the
indexer travels to the next state in the table. The direction is shown with the DIR pin high and the RDIR bit in the
CTRL register set to '0', or the DIR pin low and the RDIR bit set to '1'. If the DIR pin is low with the RDIR bit '0',
or the DIR pin is high with the RDIR bit '1', the sequence is reversed. Positive current is defined as xOUT1 =
positive with respect to xOUT2.
Note that if the step mode is changed while stepping, the indexer will advance to the next valid state for the new
MODE setting at the rising edge of STEP.
12
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