SLOU535 June 2019
A header connector with 0.100-inch pitch (J3) provides access to the DRV8428x signals. This can be used for measurement or as a connector to control the DRV8428x from an external microcontroller for prototype purposes. To disconnect the on-board MSP430 microcontroller, remove related zero ohm resistors between the MSP430 and the J3 header. Table 1 describes the connections available on the J3 header. Each header pin is labeled on the evaluation module and connects to a similarly named pin of the DRV8428x.
| Header Label | Description |
|---|---|
| MCU 3.3 V | 3.3 V rail for the on-board MSP430 and nFAULT LED |
| nFAULT | EN/nFault pin. |
| VREF/VREFB | Current set reference input (DRV8428x) or Bridge B.current set reference input (DRV8428xE/P). |
| MO/VREFA | Microstepping mode-setting pin (DRV8428x) or Bridge A.current set reference input (DRV8428xE/P). |
| TOFF/DECAY | Sets the Decay mode and off time during current chopping. |
| DECAY0/BDECAY | No connection |
| DECAY1/ADECAY | No connection |
| M1/BPH/BIN2 | Microstepping mode-setting pin (DRV8428x); or Bridge B phase input (DRV8428xE) or PWM input (DRV8428xP). |
| STEP/BEN/BIN1 | STEP pin (DRV8428x); or Bridge B enable input (DRV8428xE) or PWM input (DRV8428xP). |
| DIR/APH/AIN2 | DIR pin (DRV8428x); or Bridge A phase input (DRV8428xE) or PWM input (DRV8428xP). |
| ENABLE/AEN/AIN1 | En/nFault pin (DRV8428x); or Bridge A enable input (DRV8428xE) or Bridge A PWM input (DRV8428xP). |
| nSLEEP | Sleep mode input. |
| GND | Ground |