Schematic Design For esp32

  • Hello guys
    I want to create a schematic design for a esp32 module with MPU6050 chip as well as a battery connector and a battery charger, it is similar to link text but i want to use the esp32 module not the chip.. i have already achieve this using the esp32 dev board and MPU6050 board and a battery charger as per the picture below(couldn't attach a zip file) but the issue is the battery consumption is very high and the size is very big also...
    This will be my first time trying to make my own device(Schematic) i am good using the boards and connecting them but not joining ICs on a PCB.. please any help on how to achieve this will be welcomed..

  • Hi @ZeeZa ,

    You need to build a custom board with the ESP32 SoC and the MPU6050 IMU, right?

    first, you need to select appropriate ESP32 SoC from the wide variety of model, after that using the datasheet find out the minimum configuration circuit for the SoC and add the MPU6050 module. that's all you need. the most tricky part is the minimum configuration circuit.

  • @ZeeZa I'm working on a similar type of project. As @salmanfaris has mentioned the minimum config of ESP32 is important. But, If you are trying to use the SoC versions like ESP32 WROVER then you can directly interface it with MPU6050 IC. If you're trying to use bare IC instead of the breakout board of the MPU6050 then I suggest you see this link which will give you the configuration to be made for the MPU6050 IC to interface with your MCU.

    I suggest you to even look at the datasheet of the ESP32 because they have mentioned how you must place the SoC module on PCB. You cannot place the module in the middle of the board as it causes bad reach to the antenna. The SoC must be placed at the edges of the PCB with antenna side protruding outside. There are many other design rules mentioned in the datasheet. So, Please refer it before you start your work. All the best, happy making..!!👍

  • Thanks for the replies.. so far i have been able to achieve this link text but i am having so doubts when following the datasheet of link text page 15 here is the image Esp32-Schematic.JPG , I do not understand what the JP3(Jtage) is for, can someone please explain, also i have this other link link text he did the same thing am doing but way more than mine. so i am following some of his schematics. also i have a lot of unfinished net in my schematic please how do i deal with them... Thanks

  • @ZeeZa JP3 in the schematic means Jumper slots for JTAG connections. jtag is nothing but an IEEE standard used for programming and debugging the microcontrollers. It is more sophisticated than other protocols so far. So, In order to program your MCU with the code that you write on your IDE, we need these pins for burning the code. You can even burn the code in prior and populate the SoC onto your PCB. But, it's more recommended to make these JTAG connections so that you can program it whenever you wanted.

  • @kowshik1729 said in Schematic Design For esp32:

    JTAG connections

    i am trying to make the pcb as slim as possible here and adding the jumper will make it a little bigger width wise, i thought the the UART(JP1) is for uploading the code to the esp module as it is connected to TXDO and RXDO or is it only serving as a power connect in this schematic?

  • @ZeeZa The JP1 UART jumper doesn't serve as the power connect. It is meant for extending the UART pins so that you can access them. JTAG is responsible for uploading the code and I understand that you are not ready to compromise over the size of PCB. So, I suggest you use CP2102 USB to UART converter where you can just connect your mini USB cable and upload the code. This is even easier, but if you see the ESP32 development module, it is just the same board where ESP32 SoC is fit which can be accessed with a USB to UART converter.

    You can use these JST Jumper slots

    for extending the JTAG pins. These are a little small and can reduce the width of the PCB. Please let us know in case of queries. You ca easily find the footprints of these connectors in your PCB designing softwares.

  • am sorry if i am asking some basic question i still cant get my head wrap around the JTAG pins, let say i have the JTAG in my pcb how will i use the pin to program the device from my Laptop(IDE) or is the Jtag used the same way we use the ESP-01 which we connect to Arduino UNO rx and tx pin before we can upload the code on it?

  • @ZeeZa JTAG Programmer for ESP32

    You can programme your board using the JTAG pins on your PCB by connecting them to the JTAG pins of the programmer board.

  • @ZeeZa Have you figured out a way how to programme your ESP32 using UART pins?? If not Well, I did found out a way. please this link ESP32 UART UPLOAD

    alt text

    May be this might help you out..!! Please try out and let me know your output.

  • @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.

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