ESP32 Forum

Hello, I am designing a device which uses esp32-s3-wroom-1 to get data from SPI and send it through WiFi.

My first questions is, I think I only need power,SPI and flashing pins to attach in my schematic and no other component because Wroom-1 module already has the parts in esp32 s3 reference sheet.

For the second question,

Here https://docs.espressif.com/projects/esp ... ction.html it is mentioned that esp32 s3 can be programmed via both usb or uart. I am not thinking a onboard programmer circuit, I want to leave some ports on pcb and flash the esp with them. For this side I have couple things in my mind:

If I use a CP2102 module like this: CP2102 flash the esp32, should I just put a 6 pin header for RX,TX,VCC,GND,EN,RST and use 2 transistors before EN and RST pins.

2)In CP2102 case, should ESP be powered only from CP2102 while programming or can the external 3v3 source stay on directly(Or maybe with diodes )

3) For usb programming, should I just use a 2-pin header for GPIO 19-20 and add buttons for EN,RST pins, then just connect D+ and D- to usb-c connector.

I have not started designing this part yet so unfortuantely there are no schematics but I can post them after adding if needed.

Also I am using the 1U module for this development and without any antenna I am able to send data through WiFi, is there an integrated antenna inside the module(Couldnt see it in the datasheet) or is the traces acting like antenna for a short range.

If I use a CP2102 module like this: CP2102 flash the esp32, should I just put a 6 pin header for RX,TX,VCC,GND,EN,RST and use 2 transistors before EN and RST pins.

What you need to flash it is just RX and TX. The transistors which you can see in dev kit schematic are driven by UART ctrl signals to generate RESET and BOOT signals. Nice to have but can be replaced by 2 push buttons.

In CP2102 case, should ESP be powered only from CP2102 while programming or can the external 3v3 source stay on directly(Or maybe with diodes )

Looking into some CP2102 datasheet, it can source up to 100 mA on 3V output. Not enough for ESP32-S3. You need at least 500mA

For usb programming, should I just use a 2-pin header for GPIO 19-20 and add buttons for EN,RST pins, then just connect D+ and D- to usb-c connector

Yes, that should be enough.

If I use a CP2102 module like this: CP2102 flash the esp32, should I just put a 6 pin header for RX,TX,VCC,GND,EN,RST and use 2 transistors before EN and RST pins.

What you need to flash it is just RX and TX. The transistors which you can see in dev kit schematic are driven by UART ctrl signals to generate RESET and BOOT signals. Nice to have but can be replaced by 2 push buttons.

In CP2102 case, should ESP be powered only from CP2102 while programming or can the external 3v3 source stay on directly(Or maybe with diodes )

Looking into some CP2102 datasheet, it can source up to 100 mA on 3V output. Not enough for ESP32-S3. You need at least 500mA

For usb programming, should I just use a 2-pin header for GPIO 19-20 and add buttons for EN,RST pins, then just connect D+ and D- to usb-c connector

Yes, that should be enough.

Thank you for the answers. I want my design to be as small as possible and I will flash the code to esp max 2-3 times therefore I do not prefer to add switch buttons. If 2 pins for USB-C programming is enough, I am thinking to just place 4 pads for EN, RST, GPIO19, and GPIO20. The ESP will already be powered from another power source, so maybe I can design a small programming board for it which includes a USB-C port for data/power and 2 switch buttons to power the EN,RST pins when needed so that I can put the board in programming mode. Do you think this would work?

For usb programming, should I just use a 2-pin header for GPIO 19-20 and add buttons for EN,RST pins, then just connect D+ and D- to usb-c connector
Yes, that should be enough.

You need GND too. If you have no need to manually reset it you dont need buttons for EN and reset.

For usb programming, should I just use a 2-pin header for GPIO 19-20 and add buttons for EN,RST pins, then just connect D+ and D- to usb-c connector
Yes, that should be enough.

You need GND too. If you have no need to manually reset it you dont need buttons for EN and reset.

Thank you, but how will I put the module to programming mode without them. In my later reply I thought of a board which takes care of the switch buttons but if you say that there is no need for it, will the code just flash to the module without doing anything to EN and RST pins

how will I put the module to programming mode without them

Its taken care of automatically. You only need the buttons when using the UART pins.

Its taken care of automatically.

...in most of the cases yes, but you might mess the image so badly that you need to enter "download mode" by hand (it happened to me once).
So my recommendation is to place some headers or at least leave the pads accessible, for emergency situation.
Buttons are needed no matter if you use UART or Jtag/USB

Buttons are needed no matter if you use UART or Jtag/USB

They are not needed for USB.