ESP Prog


ESP Prog is ESP32 Programmer board.

It can be used in multiple ways like use it for programming ESP8266, ESP32, or any other microcontroller which needs boot Pin and Reset Pin control along with UART RX, and TX for flashing the MCU with a new program.

Or, one can also use it as a USB to UART adapter.

We see many designs where developers put the USB to UART (with auto reset and boot) on their custom hardware so that with the same interface they will be able to reprogram the board as well in the production & field easily.

But, this is not recommended because this poses a risk.

Someone can hack your hardware to do something else with their own firmware, or break it easily to make you look bad in front of the customer, all these things happen in real life.

So, you should not have an easy way exposed, to reflash your MCU.

What you should do is, have a 6-pin connector(RX, TX, 3.3V, GND, EN, IO0) on the board and buy a programmer board to do the programming in the production. For the field to have a secured OTA or secured physical interface.


  • Made in India
  • Compact size: 50mmx30mm
  • USB-C Type Interface: you can connect a USB in any direction. Use USB-A to USB-C Cable.
  • LEDs for Power, RX, TX
  • Switch for Reset and Boot
  • Both 3.3V and 5V are available on the O/P connector
  • All signals on a standard 2.54mm Pitch Header (Header will come along with the board (unsoldered))
  • We test each and every ESP32 Programmer board before shipping

ESP Prog Pinout

  1. 3.3V DC (100mA Max.)
  2. TXD
  3. RXD
  4. GND
  5. Reset/RTS
  6. Boot/DTR
  7. GND
  8. 5V DC (500mA Max.)

ESP PROG Connections

How ESP32 Programmer Works

Thanks to the Binay Updates for the video.

Silab CP2102 USB Driver

You can download and install the driver from Silab’s website in case your PC doesn’t have a driver already installed.

After the driver is installed, when you plug the USB to RS485 converter into your PC’s USB port, one COM port will appear in Device Manager(for windows).

Connection with Custom Hardware

Application Board – 1


An 8-Pin 90-degree angled male header is included in the package. Each unit is ~7.6 grams

Motivation behind ESP32 Programmer?

We at CAPUF Embedded aim to build tools that empower companies and their engineers to build embedded products easily.

In the last couple of months, we designed quite a few custom-embedded products for our customers where we used ESP32 for Wi-Fi connectivity.

The challenge we faced was with the ESP32 Flash programming once the board is ready.

There is no ESP32 programmer board available in the market that can be used for programming the production boards easily.

Atleast we were not able to find it easily which we can buy and use it.

To handle the situation, we had to use readily available ESP32 Dev kits, we took out the ESP32 module from them, and then took RX, TX, Boot, and Reset pin along with 3.3V and GND signals onto a header connector via small cable and used it as ESP32 programmer.

See, it looked like shown below 

That’s when it struck our mind that this could be a useful board for hundreds of companies that are building embedded products using the ESP32 module.

They might also be struggling as we did. That’s how this board came into existence.

Cost of ESP32 Programmer

You can buy from our Distribution Partners.

Our Partners in India

rare components

Ktron electronic components Web shop

Our Partners in North America

KJD Electronics
Ships globally

by KJD Electronics