Designed Custom PCB using ESP32 S3 without Boot Button (cannot put ESP32 in download mode)

[Ukaton]

Hi,

I recently designed and manufactured a custom PCB with PCBWay using the ESP32S3-1-N16 microcontroller and when I try to upload firmware via PlatformIO that worked on a previous PCB design, I get an error message saying:
"

Code: Select all

Uploading .pio/build/esp32-s3-devkitc-1/firmware.bin
esptool.py v4.2.1
Serial port /dev/cu.usbserial-0001
Connecting......................................

A fatal error occurred: Failed to connect to ESP32-S3: Wrong boot mode detected (0xb)! The chip needs to be in download mode.
For troubleshooting steps visit: https://docs.espressif.com/projects/esptool/en/latest/troubleshooting.html"

In a previous design, I had designed a PCB with an ESP32 WROOM module where the EN pin was connected to RESET and I didn't have a BOOT button and it works perfectly. As a logical next step, I wanted to update the PCB by replacing a micro USB receptacle with a USB C receptacle as well as replace the ESP32 WROOM module with a ESP32S3-1-N16 module. I even tested this design using a ESP32S3-dev-kit-C to make sure my original firmware from the original design worked on the new design (give or take renaming certain GPIOs due to a different pin mapping) and it worked just fine. But when I designed my latest PCB, I didn't add and connect a BOOT button that existed on the ESP32S3-dev-kit-C. Here are some screenshots of my current schematic's ESP32S3 module

ESP32S3-1-N16

Screen Shot 2022-12-27 at 5.12.32 PM.png (123.8 KiB) Viewed 3512 times

as well as the associated RESET schematic

Reset

Screen Shot 2022-12-27 at 5.13.57 PM.png (129.18 KiB) Viewed 3512 times

. What should I do to mitigate the above error so that I can successfully upload new firmware given that I cannot switch between "Boot" and "Download" modes? Any help or guidance would be greatly appreciated!

[ESP_Sprite]

Why is your two-transistor auto-reset circuit connected to GPIO48 rather than GPIO0?

[Ukaton]

I mistakenly remapped the original pin from GPIO0 to GPIO48 to make re-routing easier since GPIO0 on both WROOM and the S3 were on different sides of the module. I got carried away and completely neglected the fact that GPIO0 needed to be connected to the auto reset circuit instead of GPIO48... is it possible to mitigate this in a non-trivial way or is this PCB a lost cause?

[ESP_Sprite]

is it possible to mitigate this in a non-trivial way or is this PCB a lost cause?

Depends. If you want to check the PCB as pre-production or only need a few PCBs, you can probably rework it as you're using a module with the pads available: simply cut the trace to GPIO48 and run a bodge wire from Q2 to IO0. If you mean 'mitigate' as in 'without PCB modifications', sorry, that's not possible.

[ddodge]

Were you able to figure out your issue? Do you have a schematic you are willing to share that allows for a successful upload without needing a Boot button 100% of the time?