user
trying to connect a drv8825 to an arduino mega (wokwi doesn't have the same driver so using a substitute). how does this look:


{
  "version": 1,
  "author": "ger",
  "editor": "wokwi",
  "parts": [
    { "type": "wokwi-arduino-mega", "id": "mega", "top": 0, "left": 0, "attrs": {} },
    { "type": "wokwi-a4988", "id": "drv1", "top": 216, "left": 513.6, "attrs": {} },
    {
      "type": "wokwi-stepper-motor",
      "id": "stepper1",
      "top": 326.19,
      "left": 641.97,
      "rotate": 180,
      "attrs": { "size": "17" }
    },
    { "type": "wokwi-gnd", "id": "gnd1", "top": 49.4, "left": 585.4, "rotate": 180, "attrs": {} },
    { "type": "wokwi-vcc", "id": "vcc1", "top": 39.16, "left": 556.8, "attrs": {} }
  ],
  "connections": [
    [ "stepper1:B-", "drv1:2B", "green", [ "v0" ] ],
    [ "drv1:2A", "stepper1:B+", "green", [ "h0" ] ],
    [ "drv1:1A", "stepper1:A+", "green", [ "h0" ] ],
    [ "drv1:1B", "stepper1:A-", "green", [ "h0" ] ],
    [ "mega:GND.5", "drv1:GND.1", "black", [ "v145.55", "h166.6", "v-28.8" ] ],
    [ "drv1:DIR", "mega:51", "green", [ "h-76.8", "v-136" ] ],
    [ "drv1:STEP", "mega:49", "green", [ "h-48", "v-134.4" ] ],
    [ "drv1:MS1", "mega:29", "green", [ "h-19.2", "v-192" ] ],
    [ "drv1:MS2", "mega:31", "green", [ "h-28.8", "v-182.4" ] ],
    [ "drv1:VMOT", "vcc1:VCC", "red", [ "h0" ] ],
    [ "drv1:GND.2", "gnd1:GND", "black", [ "h0" ] ],
    [ "drv1:ENABLE", "mega:GND.4", "black", [ "h0" ] ],
    [ "drv1:RESET", "drv1:SLEEP", "red", [ "h-9.6", "v9.6" ] ],
    [ "drv1:SLEEP", "mega:5V.2", "red", [ "h-38.4", "v-259.2" ] ]
  ],
  "dependencies": {}
}
Show more

---

assistant
For a DRV8825, using the A4988 model in Wokwi is generally fine because the STEP/DIR interface is nearly identical. Looking at your wiring:

Things that look correct

✅ Stepper coils connected to 1A/1B and 2A/2B.

✅ STEP and DIR connected to Mega pins:

STEP -> D49
DIR  -> D51

✅ RESET tied to SLEEP:

RESET -> SLEEP

✅ SLEEP pulled high:

SLEEP -> 5V

✅ ENABLE tied low (always enabled):

ENABLE -> GND

✅ Logic ground connected between Mega and driver:

Mega GND -> Driver GND
Missing connection: VDD

This is the big one.

On a real A4988/DRV8825 you need:

Arduino 5V -> VDD
Arduino GND -> GND

I don't see a connection to the driver's logic supply pin (VDD).

Without that, the STEP/DIR inputs won't have power.

Check whether the Wokwi A4988 part exposes a VDD pin. If it does, connect:

JSON
["drv1:VDD", "mega:5V.1", "red", ["h0"]]
Missing motor supply capacitor

Real DRV8825 boards require a capacitor across VMOT and GND, typically:

100µF electrolytic
VMOT ↔ GND

Wokwi won't care, but real hardware often behaves erratically or dies without it.

Microstepping pins

You have:

MS1 -> D29
MS2 -> D31

but MS3 is not connected.

For a DRV8825:

MS1	MS2	MS3	Mode
L	L	L	Full step
H	L	L	1/2
L	H	L	1/4
H	H	L	1/8
L	L	H	1/16
H	L	H	1/32

If you're controlling microstepping from software, add:

MS3 -> D33

Otherwise tie it to GND or 5V as needed.

Motor voltage

You've got:

VMOT -> VCC component

which is fine in simulation.

For a real DRV8825:

VMOT = 8.2V–45V

Don't power the motor from the Arduino's 5V rail unless it's a very tiny motor and you've verified the current requirements.

One thing I'd add

DRV8825 also has a FAULT pin. It's optional, but if you want fault detection:

FAULT -> Mega input pin

with a pullup.

Summary

For a real DRV8825 I'd expect:

Mega 5V  -> VDD
Mega GND -> GND

STEP -> D49
DIR  -> D51

ENABLE -> GND
RESET  -> SLEEP
SLEEP  -> 5V

MS1 -> D29
MS2 -> D31
MS3 -> D33 (or fixed)

VMOT -> external motor supply
VMOT/GND -> 100µF capacitor

Motor coils -> 1A/1B/2A/2B

If you can show the code as well, I can verify that the pin assignments and stepping logic match the wiring.

---

user
ok, how would I add two more steppers (and two more driver boards), which pins. I think two motors would need precision to microstepping, but one would not.

I also want to avoid pins used here so I can combine projects:


{
  "version": 1,
  "author": "Anonymous maker",
  "editor": "wokwi",
  "parts": [
    { "type": "wokwi-arduino-mega", "id": "mega", "top": 10.2, "left": -3.6, "attrs": {} },
    {
      "type": "wokwi-microsd-card",
      "id": "sd1",
      "top": 294.83,
      "left": -21.47,
      "rotate": 270,
      "attrs": {}
    },
    {
      "type": "board-ssd1306",
      "id": "oled1",
      "top": 291.14,
      "left": 86.63,
      "attrs": { "i2cAddress": "0x3c" }
    },
    {
      "type": "wokwi-pushbutton",
      "id": "btn1",
      "top": 335.4,
      "left": 214.2,
      "rotate": 90,
      "attrs": { "color": "green", "xray": "1" }
    },
    {
      "type": "wokwi-pushbutton",
      "id": "btn2",
      "top": 335.4,
      "left": 339,
      "rotate": 90,
      "attrs": { "color": "green", "xray": "1" }
    },
    {
      "type": "wokwi-pushbutton",
      "id": "btn3",
      "top": 335.4,
      "left": 271.8,
      "rotate": 90,
      "attrs": { "color": "green", "xray": "1" }
    }
  ],
  "connections": [
    [ "mega:GND.2", "oled1:GND", "black", [ "v74.7", "h-49.45" ] ],
    [ "mega:3.3V", "oled1:VCC", "gold", [ "v45.9", "h-20.75" ] ],
    [ "sd1:VCC", "mega:5V", "red", [ "v-57.6", "h135.84" ] ],
    [ "sd1:GND", "mega:GND.2", "black", [ "v-38.4", "h153.71" ] ],
    [ "mega:52", "sd1:SCK", "orange", [ "v49.7", "h-341.79" ] ],
    [ "sd1:CS", "mega:53", "#8f4814", [ "v-28.8", "h355.26", "v-97.1" ] ],
    [ "mega:2", "sd1:CD", "green", [ "v-47.4", "h197.6", "v259.2", "h-441.6" ] ],
    [ "mega:50", "sd1:DO", "yellow", [ "v-8", "h-428.2" ] ],
    [ "mega:51", "sd1:DI", "cyan", [ "v1.6", "h26.2", "v96", "h-355.11" ] ],
    [ "mega:20", "oled1:SDA", "purple", [ "v-37.8", "h98", "v306.6", "h-268.87" ] ],
    [ "mega:21", "oled1:SCL", "gold", [ "v-28.2", "h78.9", "v287.4", "h-269.1" ] ],
    [ "btn1:1.r", "mega:26", "magenta", [ "v19.4", "h278.4", "v-364.8", "h-180.2" ] ],
    [ "btn2:1.r", "mega:26", "magenta", [ "v19.4", "h144", "v-365.85" ] ],
    [ "btn3:1.r", "mega:26", "magenta", [ "v19.4", "h220.8", "v-365.85" ] ],
    [ "mega:25", "btn3:1.l", "white", [ "v0.95", "h83.8", "v268.8", "h-134.4" ] ],
    [ "btn1:1.l", "mega:24", "#8f4814", [ "v-28.8", "h182.4", "v-260.15" ] ],
    [ "mega:23", "btn2:1.l", "#8f4814", [ "v1.1", "h93.4", "v288", "h-67.2" ] ]
  ],
  "dependencies": {}
}


Also, here:


{
  "version": 1,
  "author": "Anonymous maker",
  "editor": "wokwi",
  "parts": [
    { "type": "wokwi-arduino-mega", "id": "mega", "top": 0, "left": 0, "attrs": {} },
    {
      "type": "wokwi-potentiometer",
      "id": "pot1",
      "top": 242.1,
      "left": 413.8,
      "rotate": 180,
      "attrs": {}
    },
    {
      "type": "wokwi-rgb-led",
      "id": "rgb1",
      "top": 234.4,
      "left": 193.1,
      "rotate": 180,
      "attrs": {}
    }
  ],
  "connections": [
    [ "mega:GND.5", "pot1:GND", "black", [ "v59.15", "h89.8" ] ],
    [ "mega:A0", "pot1:SIG", "green", [ "v36.3", "h233.1" ] ],
    [ "pot1:VCC", "mega:5V.2", "red", [ "v0" ] ],
    [ "rgb1:COM", "mega:GND.4", "black", [ "v-23", "h147.7" ] ],
    [ "rgb1:B", "mega:8", "blue", [ "v-42.6", "h-209", "v-240", "h186.6" ] ],
    [ "rgb1:G", "mega:7", "green", [ "v-33", "h-227.9", "v-259.2", "h211.2" ] ],
    [ "rgb1:R", "mega:6", "red", [ "v-23.4", "h-255.4", "v-278.4", "h220.8" ] ]
  ],
  "dependencies": {}
}


But I only need a reasonable interface, maybe the potentiometer plus a button is enough and could be merged.
Gimme a list.
I want to do a schematic on KiCAD.
Show more

---

assistant
Given everything you've shown, I'd reserve pins in a way that's easy to remember and leaves room for future expansion.

Already occupied
SPI / SD card
50 MISO
51 MOSI
52 SCK
53 CS
I2C OLED
20 SDA
21 SCL
Buttons
23 Button 1
24 Button 2
25 Button 3
26 Common button rail
Potentiometer
A0
RGB LED
6 Red
7 Green
8 Blue
I'd move your first stepper

You originally had:

STEP = 49
DIR  = 51
MS1  = 29
MS2  = 31

But 51 is already MOSI.

While it can be shared if the SD card isn't active, I'd avoid it.

Proposed Mega pinout
Stepper 1 (high precision)
STEP1    40
DIR1     41
MS1_1    42
MS2_1    43
MS3_1    44
Stepper 2 (high precision)
STEP2    45
DIR2     46
MS1_2    47
MS2_2    48
MS3_2    49
Stepper 3 (full-step only)
STEP3    30
DIR3     31

Tie:

MS1 = GND
MS2 = GND
MS3 = GND

on the board.

Shared signals

For all three DRV8825s:

RESET -> SLEEP
SLEEP -> 5V
ENABLE -> GND

No Arduino pins needed.

Optional enable control

If later you want software power-down:

ENABLE1 32
ENABLE2 33
ENABLE3 34

Not required initially.

Resulting usage map
6   RGB R
7   RGB G
8   RGB B

20  SDA
21  SCL

23  Button
24  Button
25  Button
26  Button common

30  STEP3
31  DIR3

40  STEP1
41  DIR1
42  MS1_1
43  MS2_1
44  MS3_1

45  STEP2
46  DIR2
47  MS1_2
48  MS2_2
49  MS3_2

50  MISO
51  MOSI
52  SCK
53  SD CS

A0  Potentiometer
If this is for a KiCad PCB

I'd strongly consider not wiring MS1/MS2/MS3 directly to Arduino pins.

Instead put a 3-pin jumper block (or DIP switch) on each driver:

MS1 -> jumper
MS2 -> jumper
MS3 -> jumper

Then:

Stepper 1 fixed at 1/16 or 1/32

Stepper 2 fixed at 1/16 or 1/32

Stepper 3 fixed at full step

That saves 6 Arduino pins and simplifies the firmware considerably. In most projects, microstepping mode is chosen once and never changed during operation.

My KiCad version would probably be:

Stepper 1:
STEP 40
DIR  41

Stepper 2:
STEP 45
DIR  46

Stepper 3:
STEP 30
DIR  31

All microstep settings:
DIP switches / jumpers

which uses only 6 digital pins total for three motors and leaves the Mega with plenty of I/O for limit switches, sensors, encoders, relays, etc. later.