Schematic Design For esp32

  • @kowshik1729
    i tried the link you gave and i don't have most of the components they used especially the ESP32-S so i tried improvising, i used the arduino and DOIT ESP32 DEVKIT V1, i can't upload to my DOIT board cause the USB port got damaged so i tried connect to arduino the same way they connect to the FDTI in the circuit, i didnt border about the buttons cause it is already on the DOIT board.
    After all the connections, when i tried uploading i was not able to connect to the DOIT board i got "
    A fatal error occurred: Failed to connect to ESP32: Invalid head of packet (0x0A)"
    I tried holding the boot button down also but got the same error.

  • @kowshik1729
    I'm still on the pcb design, can you check link text and give a feedback(the pcb wring) and also do i have to worry about unest pins and final question do the usb to uart ic consume power when i connect the device to a battery power? still not decided over uart and jtag yet..

  • @ZeeZa For your question over USB-UART power consumption thing, ofcourse the power will be consumed by every IC on your board, but power will be utilized by that board only when you use it. If you are not uploading the code then USB to UART will not consume much power. So, don't you worry about it.! I will get back to you with remaining answers.

  • thanks for the answers @kowshik1729 but before you answer the remaining question i have some few more,
    in this schematic 3.3K(1%)(NC) and 10uF/25V(10%)(NC) i assume that they do not need to be connected, Is that correct?

  • @ZeeZa In the circuit diagram shown by you, if you closely analyze any voltage regulation circuit, it can be known that we need 2 capacitors for sure in order to make the voltage regulator operate properly. I'll tell u why should we use them,

    1. Capacitors are devices that can store charge(You obviously know it right...!!!), So by using this property of capacitors (aka caps) small valued capacitors of order 1-100uF are used for reducing voltage transients. Voltage transients mean, when high amounts of voltage is flodedd to an input, there will be sudden spikes in the flow of current. This will damage the device. So, by putting capacitors at the input and output creates a virtual low-resistance path which makes sloww drop in the voltage(Like an decaying exponential).

    2. So, how what values of caps you must place now? At the input you must put higher capacitance value relative to the output side.
      For normal uses for LM7805 regulator at
      Input - 10uF capacitor
      Output - 0.1uF capacitor
      Typically these values must be fine.

    Coming to the resistor, I guess it is used as current limiting resistor. You can put just 2 capacitors at input and output and rest of the components can be ignored. But, in minimum config schematics they give those capacitors for stable power supply so if you want it you can put those components. Else you can abstain from populating them. If any queries please revert back.!

  • Thanks for your kind explanations, but in that circuit it already have an input EXT_5V capacitor C1 which is 10uF and a output of 22uF at c3 before going to power VDD33, my question here is the R25 resistor and R24(what does 0R even mean) and C23 capacitor are they really needed in the circuit? i mean if like you said every ic on a pcb board take little bit of power so why populate it with unnecessary resistors and capacitors. and also how can i simulate this link text circuit, i am still looking for simulation mode on easyeda for the past 2 days... still looking...

  • @ZeeZa Regarding the 0R resistor, it means that the value of resistance is ZERO it acts as a virtual short path by providing little rugged path than a normal copper wire. The main use of this 0R resistances is that it gives stable transients at output and input terminals. But it is redundant, meaning you need not necessarily include it in your schematics always. C23 and R25 can also be skipped. So, by consolidating all the above changes the final schematic can be something like this
    For simulation part, you don't have to necessarily use only easy EDA, you can use softwares like Proteus or Fritzing like that.

  • Thanks for your amazing explanations... but still not done yet
    i have this power switching circuit

    i have a little doubt about the mosfet in the circuit basically when there is a voltage in the V1(5v) it gets divided before going to the gate then the gate turns on the mosfet that is the USB(V1) power is used by the device, what i dont understand is the VBAT(V2) should be connect to the drain or source of the mosfet, i think it should be the source but there is a diode between the drain and the source which will be forward bias if current is flowing from the drain(I might be wrong), which mean current wont flow from source to the drain.

  • @ZeeZa I'm really really sorry that I couldn't help you with this question alone. Because I'm really not that good regarding the MOSFET's thing but I can answer if you could afford me some time. Sorry about that.

  • That's alright @kowshik1729 i will check other forum and also await your answer. also i am trying to calculate the pcb track width and via diameter for the board, i am asking since we printing similar boards.

Log in to reply

Recent Posts

  • R

    thank youu

    read more
  • @Richu-Bini thanks for posting the question . just for a brief about pwm, pulse width modulation technique is a method to change the duty cycle of a wave. Which means you can determine how much time a signal must be on or off.

    So, coming to the question, software pwm and hardware pwm is just two different ways of producing same result. In software(referring Arduino here) you'll just write a value between 0 to 255 inorder to determine duty cycle percentage. For example 0 is 0% duty cycle which means the cycle is on for 0% of whole time, similarly 127 means 50% of time cycle will be on and 255 means signal will be on for ever. This is regarding software.

    Coming to hardware, you can generate a pwm signal using very simple passive component, called as potentiometer and 555 timer IC by using 555 timer as bistable multivibrator(The generated output will have two stable states 0 and Vmax, hence the name bistable) and changing the resistance using a potentiometer generates different duty cycles. This is the difference between hardware and software pwm. Please let me know if I haven't explained what you have expected.

    read more
  • Kerala Java User group Februaruy Meetup.png

    This month we are discussing Psychology and Perils of Polyglot/Mixed Language Programming

    by Praseed Pai

    Author of .Net Design Patterns and
    C++ Reactive Programming,
    Father of SLANG Compiler.

    Nowadays, every developer in the world ought to be a Polyglot (Programmer) to do something worthwhile in the industry. But, most are not prepared to get into that groove. The Session will give necessary conceptual, ontological, linguistic and formal background to navigate between programming languages with ease. The Session has got examples in C++, C#, Java, Scala, Python, JS, Python/C interface, Java Native Interface, P/Invoke, COM interop, RxJava/RxJS./Rxcpp/ etc. All code snippets are taken from real-life projects which the presenter has been part of, in the past two decades. The session also covers some pitfalls which an aspiring Polyglot Programmer should be watchful, as well.

    Don't miss it, book your seats today. It's a golden opportunity for all Enthusiasts to listen from the true industry experts!

    Come and join​ us! Have a Java Coffee 🙂

    Date & Time : 29th February 2020 02:30 PM to 05:30 PM

    Location       : KeyValue Software Systems Pvt Ltd, SmartCity Kakkanad
    Map :

    Grab your ticket at:

    read more
  • R

    What is the difference between hardware pwm and software pwm

    read more
  • Flat/ball end

    alt text

    flat end leaves flat surface profile on the stock and are good for removing large volume of material, but steps are formed when used for making curved surfaces. Ball end leaves curved surfaces and forms smooth curved finish while cutting cavities. They are used for finishing cuts.

    read more