ESP32-DevKitC V4 schematics help

Omri_Sap2020
Posts: 2
Joined: Mon Feb 10, 2020 3:48 pm

ESP32-DevKitC V4 schematics help

Postby Omri_Sap2020 » Mon Feb 10, 2020 4:06 pm

Hi,
My goal is to create a pcb of my own that inclueds an esp32, which I am able to upload a code into it externally(with an FTDI module or similiar,for example this one: https://amzn.to/2SgsEiA). For this I encountered a few issues looking at the sketch:
1. Connected to 3.3v on ESP-WROOM-32 are 2 capacitors: 0.1uF, 22uF. What are their parts? I also have a AMS1117-3.3 beside the esp that is connected at output to 22uF. Does this make the first 22uF redundant?
2. I can see in the schematic that RX,TX, EN and IO0 are coming from the UART conversion part, with using DTR and RTS. Is this absolutly neccessary for esp32? what is the part of IO0, and is EN ok being just high all the time?
3. In my FTDI module there are a CTS, DTR pins - how do I utilize them(do I need to?)?
Thanks in advance.

mikemoy
Posts: 448
Joined: Fri Jan 12, 2018 9:10 pm

Re: ESP32-DevKitC V4 schematics help

Postby mikemoy » Mon Feb 10, 2020 7:40 pm

I think your getting to far ahead of yourself. You need to do more reading than plowing into making a PCB.
1. Connected to 3.3v on ESP-WROOM-32 are 2 capacitors: 0.1uF, 22uF. What are their parts? I also have a AMS1117-3.3 beside the esp that is connected at output to 22uF. Does this make the first 22uF redundant?
Part of that depends on how close the regulator / caps are to the part your are powering & if 22uf is enough for that particular regulator to regulate properly, along with is that enough capacitance for the IC' you are driving.
2. I can see in the schematic that RX,TX, EN and IO0 are coming from the UART conversion part, with using DTR and RTS. Is this absolutly neccessary for esp32? what is the part of IO0, and is EN ok being just high all the time?
If you dont know what GPIO0 and EN are doing you really should take some time and read the ESP32 data sheet. We could give you the quick answer here, but then how would you learn anything. A short answer is GPIO0 and EN are used to put the chip in flash mode.
3. In my FTDI module there are a CTS, DTR pins - how do I utilize them(do I need to?)?
If you want to flash the part, then yes you need to.

Omri_Sap2020
Posts: 2
Joined: Mon Feb 10, 2020 3:48 pm

Re: ESP32-DevKitC V4 schematics help

Postby Omri_Sap2020 » Thu Feb 13, 2020 12:34 pm

Hi, thanks for the answer.
Iv'e read some of the datasheet and found on other sources these findings:
IO0 is incharge of putting the chip in serial boot mode. meaning in order to upload a code I need to connect RX,TX(crossed from my FTDI - that is connected through USB to my computer), hold IO0 low, switch en to high and then press upload code from arduino ide.
Is this correct? if so, there is no need for DTR, RTS pins.
I am asking this to put as little hardware as I can, and because the FTDI module's I have RTS pin is a little hard to reach.
Thanks.

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