DRV8846_15 Datasheet, PDF (12/35 Pages) Texas Instruments – DRV8846 Dual H-Bridge Stepper Motor Driver

DRV8846
SLLSEK2 – JUNE 2014
www.ti.com
Table 2. Step Mode Settings
M1
M0
STEP MODE
0
0
Full step (2-phase excitation), rising-edge only
0
Z
1/2 step (1-2 phase excitation), rising-edge only
0
1
1/4 step (W1-2 phase excitation), rising-edge only
Z
0
8 microsteps/step, rising-edge only
Z
Z
8 microsteps/step, rising and falling edges
Z
1
16 microsteps/step, rising-edge only
1
0
16 microsteps/step, rising and falling edges
1
Z
32 microsteps/step, rising-edge only
1
1
32 microsteps/step, rising and falling edges
Note that the M0 and M1 pins are tri-level inputs. These pins can be driven logic low, logic high, or high-
impedance (Z), like the I0 and I1 pins described previously.
For 1/8, 1/16, and 1/32-step modes, selections are available to advance the indexer only on the rising edge of
the STEP input, or on both the rising and falling edges.
The step mode may be changed on-the-fly while the motor is moving. The indexer advances to the next valid
state for the new M0 / M1 setting at the next rising edge of STEP.
The home state is 45°. The indexer enters the home state after power-up, after exiting UVLO, or after exiting
sleep mode (see the yellow-shaded cells in Table 3 also indicated with a table note).
Table 3 shows the relative current and step directions for different step mode settings. At each rising edge of the
STEP input, the indexer travels to the next state in the table. The direction is shown with the DIR pin high; if the
DIR pin is low, the sequence is reversed. Positive current is defined as xOUT1 = positive with respect to xOUT2.
1/32 STEP
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17 ⁽¹⁾
18
19
20
21
22
1/16 STEP
1
2
3
4
5
6
7
8
9 ⁽¹⁾
10
11
Table 3. Relative Current and Step Directions
1/8 STEP
1
2
3
4
5 ⁽¹⁾
6
1/4 STEP
1
2
3 ⁽¹⁾
1/2 STEP
1
2 ⁽¹⁾
FULL STEP
70%
1 ⁽¹⁾
WINDING WINDING
CURRENT A CURRENT B
100%
0%
100%
5%
100%
10%
99%
15%
98%
20%
97%
24%
96%
29%
94%
34%
92%
38%
90%
43%
88%
47%
86%
51%
83%
56%
80%
60%
77%
63%
74%
67%
71%
71%
67%
74%
63%
77%
60%
80%
56%
83%
51%
86%
ELECTRICAL
ANGLE
0
3
6
8
11
14
17
20
23
25
28
31
34
37
39
42
45
48
51
53
56
59
(1) The indexer enters the home state after power-up, after exiting UVLO, or after exiting sleep mode.
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