ESP32 Forum

Hello everyone
I'm developing an IoT solution that is just a prototype for the moment. Until now i've used esp32-c3 wroom development boards, to realize the prototypes, and i've flashed the firmware through onBoard USB-Uart converter using Arduino IDE.
I would pass to the next step and realize a first round of industrial PCBs realization, by means of web service to make a series of my own custom circuits on a PCB.
What i'm interesting to know is, how to flash firmware on these circuits. In particular:
-I suppose that in the development board esp32 circuit there is a bootloader to allow flashing by Arduino IDE and Serial port, is this true?
-In this case, raw esp32 components have a native bootloader or i have to flash it, eventually, how can i flash the bootloader?
-Without the bootloader how can i flash my desired firmware from arduino IDE to the ESP32 on the custom PCB?
-I need usb2uart converter or there is an alternative way?

Please help me to solve my doubt, thank you in advance.
Cristian

The bootloader that is responsible for flashing the chips is baked into ROM in the factory in case of ESP32 chips: you do not have to (and in fact cannot) flash it; it works out of the box. On the C3, you can either use the serial port or the built-in USB to initially flash the chip. Note that if you use the latter, you might want to have a way to pull IO9 low for the initial flash.

Thank you so much, very kind
If i use usb-to-serial converter is there any routine to be executed (pulling up or down any pins or something similar)?

Moreover, if i'm working on arduino project, is there a way to make a DFU image to be flashed with built-in USB or to directly flash from arduino IDE in DFU mode or maybe is it necessary working on IDF ?

Cristian_bcc wrote: ↑

Mon Jun 26, 2023 5:32 am

Thank you so much, very kind
If i use usb-to-serial converter is there any routine to be executed (pulling up or down any pins or something similar)?

As I said, you probably want to be able to pull GPIO9 low for the initial flash.

Moreover, if i'm working on arduino project, is there a way to make a DFU image to be flashed with built-in USB or to directly flash from arduino IDE in DFU mode or maybe is it necessary working on IDF ?

No. The C3 does not have USB-OTG, and the USB-serial-JTAG module is not capable of DFU.