ESP32 development board with stepper motor driver
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
Gavan Fantom 8ca5620e5c Correct footprints for C16, C17 and D3 3 years ago
gerber Correct footprints for C16, C17 and D3 3 years ago
step32.pretty STEP32 v1 3 years ago
.gitignore STEP32 v1 3 years ago
README.md Pin assignment and other general end user documentation 3 years ago
fp-lib-table STEP32 v1 3 years ago
step32.kicad_pcb Correct footprints for C16, C17 and D3 3 years ago
step32.kicad_pro STEP32 v1 3 years ago
step32.kicad_sch Correct footprints for C16, C17 and D3 3 years ago
step32.kicad_sym STEP32 v1 3 years ago
step32.pdf STEP32 v1 3 years ago
sym-lib-table STEP32 v1 3 years ago

README.md

step32

ESP32 development board with stepper motor driver

Pin assignment

A4988 Stepper Driver

GPIO Signal
12 ~RESET
13 ~ENABLE
14 ~SLEEP
16 MS1
17 MS2
18 MS3
19 DIR
23 STEP
25 DAC

Microstepping

Resolution MS1 MS2 MS3
Full Step 0 0 0
Half Step 1 0 0
Quarter Step 0 1 0
Eigth Step 1 1 0
Sixteenth Step 1 1 1

Current limiting

The DAC pin is used to set the current limit.

The current limit is 15/23 of the DAC voltage.

Current limit DAC voltage
1A 1.533V
1.5A 2.300V
2A 3.066V

The DAC output is not optional. It must be set correctly for the stepper driver to function.

I2C Expansion

GPIO Signal
21 SDA
22 SCL

The I2C bus is terminated on this board. If not desired, remove R5 and R6, next to the I2C connectors.

End stops

GPIO Signal
34 END1
35 END2

Note that these pins can be configured either as analogue or as digital inputs, depending on the type of end stops required.

LED

GPIO Signal
2 LED

Motor connection

There are two connectors for the stepper motor. Only one should be used at a time. They correspond to the two most common ways of connecting bipolar stepper motor coils to a 4-pin header. The coil assignment is marked on the silkscreen by each connector for convenience.

Heat sink

The A4988 can operate at low currents without a heat sink. At higher currents (greater than 1 amp) a heat sink may be required.

Dimensions and mounting

The PCB is 55mm wide and 64mm high, excluding the antenna. The antenna sticks out by around 6mm.

The mounting holes are 47mm apart horizontally and 53mm apart vertically. They are inset 4mm from the sides and from the bottom edge. They are sized to accept M3 screws.

Power supply

This board can be powered either from an external 12 volt supply (2.5mm barrel jack), in which case a buck converter generates 3.3 volts for the ESP32, or directly from USB, in which case a linear regulator generates the 3.3 volt supply.

The motor can not be powered from USB. Only the low voltage circuit will be energised when powered by USB.

While the motor power is labelled as 12 volts, it should operate anywhere between 7 and 20 volts. Do not exceed 20 volts.