Datasheet
ESP32 Stepper Driver
FEATURES
- AllegroTM A5984 Microstepping Driver
- GPIO and Solder jumpers for common control mode configuration
- Onboard 3.3 Volt step-down DC/DC converter regulator via TI TPS62177
POWER SPECIFICATION
- TI TPS62177: 8 to 27 Volts DC
- A5984: 8 to 40 Volts DC*
- A5984: 2 Amp max per coil.
* Review Powering the ESP32.27 before exceeding 27 Volts.
DESCRIPTION
Take control of your Robotics, 3d printer or smart home project with this WiFi enabled stepper motor driver. The Open MYR ESP32.27 combines everything you need to control a stepper motor over WiFi utilizing an Espressif ESP32 with an AllegroTM A5984. The ESP32.27 is preloaded with Open MYR firmware for out of the box functionality, just power up and go.
APPLICATIONS
- Robotics
- 3d printing
- Smart Home
- DIY CNC
PACKAGE
TODO
Note
This datasheet describes basic functionality with the AllegroTM A5984 driver. Further review of its datasheet is recommended for advanced use.
Pin Mapping
ESP32
| ESP pin | Board |
|---|---|
| 3V3 | ESP 3.3V Supply |
| EN | NA |
| GPIO 0 | NA |
| GPIO 2 | Micro Stepping 3 |
| GPIO 5 | J5 Pin 11 |
| GPIO 12 | Micro Stepping 1 |
| GPIO 13 | Motor Direction |
| GPIO 14 | Micro Stepping 2 |
| GPIO 15 | NA |
| GPIO 16 | Motor Step |
| GPIO 17 | LED Indicators |
| GPIO 18 | J5 Pin 5 |
| GPIO 19 | J5 Pin 7 |
| GPIO 21 | IO21 |
| GPIO 22 | IO22 |
| GPIO 23 | J5 Pin 9 |
| GPIO 25 | J5 Pin 6 |
| GPIO 26 | J5 Pin 8 |
| GPIO 27 | Motor Enable |
| GPIO 32 | J5 Pin 10 |
| GPIO 33 | J5 Pin 12 |
| GPIO 36 | Analog input |
| RESET | ESP Reset |
| RXD | Serial Rx |
| TXD | Serial Tx |
| GND | Ground connection |
A5984
| A5984 pin | Board |
|---|---|
| VBB1 | VCC |
| VBB2 | VCC |
| DIR | ESP GPIO 13 |
| ENABLE | ESP GPIO 27 |
| MS1 | ESP GPIO 12 |
| MS2 | ESP GPIO 14 |
| MS3 | ESP GPIO 2 |
| OUT1A | 1A |
| OUT1B | 1B |
| OUT2A | 2A |
| OUT2B | 2B |
| ROSC | SJ1, SJ2*, SJ3* |
| STEP | ESP GPIO 16 |
| VREF | Trim Pot |
| GND | Ground connection |
*via 10k Resistor
Board Congurations
The board provides capability to control the following:
- ROSC mode
- Microstepping
- Coil Current
ROSC
The three ROSC modes are available through the configuration for SJ1, SJ2 and SJ3.
| ROSC | SJ1 | SJ2 | SJ3 |
|---|---|---|---|
| GND | Closed | Open | Open |
| GND via 10k | Open | Closed | Open |
| 3.3V via 10k | Open | Open | Closed |
Micro Stepping
The Micro Stepping modes are controlled through the configuration of GPIO 2, 12, and 14.
Coil Current
Coil Current is controlled with the R20 potentiometer. Adjusting R20 clockwise will increase coil current.
Programming Port
The two by three 0.1" pin header programming port is designed to facilitate reprogramming of the ESP32. The ESP may be programmed while being powered from VCC or the 3V3 pin. The programming port implements the Auto program interface, utilizing DTR and RTS to control the EN and GPIO 0 pins.
| Pin | Function |
|---|---|
| 3V3 | 3.3 Volt DC |
| TX Serial | Tx |
| RX Serial | Rx |
| RTS | Auto Program Interface |
| DTR | Auto Program Interface |
| GND | Ground connection |
Powering the ESP32.27
The ESP32.27 has a VCC input voltage range of 8 to 27 Volts DC with a jumper installed on J6. To fully utilize the A5984 supply voltage range the jumper may be removed from J6 and an 8 to 40 Volt DC supply may be used. In this configurations the ESP32 must be powered with an additional power source. This can be achieved by using the TPS62177 with a input voltage range of 4.75 to 28 Volts DC, or providing 3.3 Volts directly to a 3.3 Volt header pin. Note for dual powered configurations, there is only one ground plane on the ESP32.27.
Auxiliary GPIO
The ESP32.27 has a few spare GPIO available for use. These GPIO are connected directly to the ESP32 and operate at 3.3 Volts DC. These GPIO pins are noted in the pin mapping section.
J5
| J5 pin | Board |
|---|---|
| 1 | GND |
| 2 | GND |
| 3 | 3V3 |
| 4 | 3V3 |
| 5 | GPIO 18 |
| 6 | GPIO 25 |
| 7 | GPIO 19 |
| 8 | GPIO 26 |
| 9 | GPIO 23 |
| 10 | GPIO 32 |
| 11 | GPIO 5 |
| 12 | GPIO 33 |