ESP32 Forum

I'm trying to build a custom microcontroller board based on the ESP32 chip (just the chip, not the WROOM module).

I've got to the point where all the power works and the USB to serial gets recognized. I'm now trying to flash the ESP, but the chip itself doesn't respond (the IDE - PlatformIO extension tries to connect to it, but it just fails).

The connections on the PCB look fine, and the LEDs for the serial communication also blink when trying to flash it. I've already found and fixed two really stupid mistakes (VDD3p3_CPU not connected to VCC and VBUS to Vs which is connected to the USB), but it's still not working.

Do i need to upload or setup some sort of bootloader on the external flash, or is something wrong with my schematic ?

If anybody could take a look at it, it would be greatly appreciated.

I'm missing loads of decoupling capacitors and I also am not seeing a power-on-reset RC network on your EN line. Also, what generates your Vcc?

Also, to answer your question: the ESP32 bootloader is in ROM; even with an empty or corrupted flash you should still be able to upload a new program.

ESP_Sprite wrote: I'm missing loads of decoupling capacitors and I also am not seeing a power-on-reset RC network on your EN line. Also, what generates your Vcc?

Also, to answer your question: the ESP32 bootloader is in ROM; even with an empty or corrupted flash you should still be able to upload a new program.

Ok I added some decoupling caps to the power inputs. I get the power from a normal LDO 3.6V (LP2985AIM5-3.6/NOPB). I also added a delay on the en signal. I don't really know if thats what you meant by "power-on-reset RC network" but this could be the problem as CHIP_PU without this will never be high.

And even if I would have a factory new ESP Chip,I wouldn't have to upload anything on the chip or the flash memory ? Just plug it in and flash some code?

Thanks for the help so far, really appreciated.

Leemme wrote: ↑

Sat Jan 07, 2023 11:07 am

And even if I would have a factory new ESP Chip,I wouldn't have to upload anything on the chip or the flash memory ? Just plug it in and flash some code?

That is correct.