Hi there,
I build my first PCB including an ESP32 and a L298N with On-Board Voltage Regulation.
Has anyone an Idea why it is unable to give output? No matter what I am doing: It always shows 0 V.
Did you connect anything to the PCB?
If so, can you imagine that it might be important to tell forum members what you connected to it?
2 Likes
Thank you for your feedback. Sure, it would be great for other users to understand my project. I added the other schematics.
Based on your schematic, I conclude that it is functioning as designed and appears to be working correctly, though perhaps not in the way you intended.
I’ll take a SWAG and assume you didn’t prototype this design before implementation. This conclusion comes from the fact that your schematic shows the outputs are always turned off. Hint: The enable pin must be set high for the outputs to function properly.
Key Points from the Data Sheet:
- Enable Pin Behavior:
- The Enable A and Enable B pins are TTL-compatible inputs.
- When these pins are low (L), the corresponding bridge (A or B) is disabled.
- To switch the motor outputs, you must set the enable pin high (H).
- Switching Note:
- For input switching, set EN = H.
- For enable switching, set IN = L.
Suggested Fix:
Ensure that the enable pins are correctly set high to allow the bridges to activate. This is a common oversight when working with the L298N module.
Helpful Resource:
Here’s a link that provides an overview and usage example of the L298N motor driver module:
How to Use the L298N Motor Driver Module
1 Like
Thanks! This means I have to cut the connection between EN and GND and connect it to the 5V, right?
Thanks!
Hi, @pascalku
Welcome to the forum.
Did you protoboard your project before going to PCB?
Can you please post some Exported jpg images of the layers of your PCB?
Thanks.. Tom.. 
No.
Connect them to Arduino outputs otherwise you will never be able to turn off the motors.
2 Likes
Do I need a resistor between those?
According to the datasheet it says
which means NO, I don't need any resistance - it would be enough to power the PIN with up to VSS (=> 12V). So anything above 2.3 V (3.3 V is clearly over this; this should be the state when setting ESP32 to HIGH signal) would be enough, right?
I've connected IO27 to ENB of L298N and tried if it works using this script:
#define ENB 27
#define In3 17
#define In4 16
void setup() {
Serial.begin(115200);
Serial.println("Hello World!");
pinMode(ENB, OUTPUT);
pinMode(In3, OUTPUT);
pinMode(In4, OUTPUT);
digitalWrite(ENB, HIGH);
digitalWrite(In3, HIGH);
digitalWrite(In4, LOW);
}
void loop() {
// put your main code here, to run repeatedly:
}
measuring ENB pin there is 3.3V coming but OUT3 & OUT4 is showing 0V.
I see that you have not read the link that was posted in reply#4.
It is important not to pass up on things that will help you understand your problem. Please read it.
You are misunderstanding that data sheet. It is only Vs which is the maximum motor supply you can use with the L298 chip. This has nothing to do with Vss which is the Logic supply voltage.
So this data sheet shows the minimum voltage that will turn on any of the L298 pins is 4V5 when you power it with 5V. Your ESP32 can only supply a signal up to 3V3. So it is not able to switch any pin on for the L298.
Hence you will not see any signals on the OUT pins, and so the motor will not move.
Thank you, I meant VS and not VSS. Fixed this and... still nothing changed! All the troubleshooting just to find out that in my schematic i am using 12VDD AND VDD12 which is clearly another label and so it was not connected to the 12V path. So fixed that aaaannnndd: It's working!
Lessons learned:
- VSS must be adjusted to "HIGH" of the MCU (which must be at least ViH to be understand as "HIGH").
- VS must be connected to a supply voltage
Thank you all for helping!