ZHCS276F September 2011 – February 2025 DRV8818
PRODUCTION DATA
Built-in indexer logic in the DRV8818 allows a number of different stepping configurations. The USM1 and USM0 pins are used to configure the stepping format as shown in Table 6-1:
| USM1 | USM0 | STEP MODE |
|---|---|---|
| 0 | 0 | Full step (2-phase excitation) |
| 0 | 1 | 1/2 step (1-2 phase excitation) |
| 1 | 0 | 1/4 step (W1-2 phase excitation) |
| 1 | 1 | Eight microsteps/step |
Table 6-2 shows the relative current and step directions for different settings of USM1 and USM0. 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.
Note that the home state is 45°. This state is entered at power-up or device reset. The HOMEn output pin is driven low in this state. In all other states the HOMEn pin is driven logic high.
| FULL STEP USM = 00 | 1/2 STEP USM = 01 | 1/4 STEP USM = 10 | 1/8 STEP USM = 11 | AOUTx CURRENT (% FULL-SCALE) | BOUTx CURRENT (% FULL-SCALE) | STEP ANGLE (°) |
|---|---|---|---|---|---|---|
| 1 | 1 | 1 | 100 | 0 | 0 | |
| 2 | 98 | 20 | 11.325 | |||
| 2 | 3 | 92 | 38 | 22.5 | ||
| 4 | 83 | 56 | 33.75 | |||
| 1 | 2 | 3 | 5 | 71 | 71 | 45 (home state) |
| 6 | 56 | 83 | 56.25 | |||
| 4 | 7 | 38 | 92 | 67.5 | ||
| 8 | 20 | 98 | 78.75 | |||
| 3 | 5 | 9 | 0 | 100 | 90 | |
| 10 | –20 | 98 | 101.25 | |||
| 6 | 11 | –38 | 92 | 112.5 | ||
| 12 | –56 | 83 | 123.75 | |||
| 2 | 4 | 7 | 13 | –71 | 71 | 135 |
| 14 | –83 | 56 | 146.25 | |||
| 8 | 15 | –92 | 38 | 157.5 | ||
| 16 | –98 | 20 | 168.75 | |||
| 5 | 9 | 17 | –100 | 0 | 180 | |
| 18 | –98 | –20 | 191.25 | |||
| 10 | 19 | –92 | –38 | 202.5 | ||
| 20 | –83 | –56 | 213.75 | |||
| 3 | 6 | 11 | 21 | –71 | –71 | 225 |
| 22 | –56 | –83 | 236.25 | |||
| 12 | 23 | –38 | –92 | 247.5 | ||
| 24 | –20 | –98 | 258.75 | |||
| 7 | 13 | 25 | 0 | –100 | 270 | |
| 26 | 20 | –98 | 281.25 | |||
| 14 | 27 | 38 | –92 | 292.5 | ||
| 28 | 56 | –83 | 303.75 | |||
| 4 | 8 | 15 | 29 | 71 | –71 | 315 |
| 30 | 83 | –56 | 326.25 | |||
| 16 | 31 | 92 | –38 | 337.5 | ||
| 32 | 98 | –20 | 348.75 |