ESP32-S3-WROOM factory USB state before Firmware is loaded

[username]

We have been using the ESP32-S3-DevKitC-1 v1.1 to help develop one of our new products. We are using the "USB" connector to flash the unit this entire time, and has worked great. Our first pass we made 100 pcb's using the ESP32-S3-WROOM-1U-N16 module. We did not put any headers on the board to flash the typical way by using EN, GPIO0, Tx & Rx. We just have the USB connector using pins 19 & 20. When we plug in our boards, the PC goes into a loop where we hear the USB plugin sound and disconnect sound about every second or two. I tried a few other boards and the same thing happens.
The only way to get around this which allows me to program them is that I have to hold GPIO0 low then tickle EN. Then I can flash them, and the next power cycle to the board they stay connected to the PC.

What is loaded on these modules from the factory that would cause the USB connection to connect and disconnect repeatedly? Seems awkward to have a module like this which is meant to be soldered to the board that the USB does not work from the factory until an app is loaded in a special way first.

Sadly, Espressif does not make a programming board for the ESP32-S3 modules like this one here. We could use this first before having the modules soldered to the board.
https://www.amazon.com/Programming-Burn ... B07FP95KM6

[ESP_Sprite]

The answer is: nothing, and that is exactly the issue. The module won't disable a watchdog until it successfully loaded at least the bootloader, and that watchdog resets the chip. Agreed on the awkwardness; for factory programming you probably either want some jig to pull IO0 low on power-up or some scripting solution where the programming starts automatically as soon as the module is plugged in. (In between disconnects, the module still is functional, and as soon as programming starts the watchdog gets disabled.)

[username]

Thanks. It sure would have been nice if they flashed it with something, even if it did nothing.
Having to implement an additional way to program a new module on the PCB for a one time use seems awkward.

I'd be ok with this if you guys came out with a programming jig for the ESP-S3 like you did for the ESP32 Wrover.
One like this.

61avZXb85cL._AC_UY218_.jpg (14.2 KiB) Viewed 2984 times

[markg85]

@username, i registered specifically to help you out here.

That very downloader board you mentioned. It works on the ESP32-S3 too. The pins the board uses are on the same position. The ESP32-S3 board has the exact same form factor size but just a couple additional pins.

Anyhow, for easy flashing, that downloader works! I'm used it just a minute before this post.

[username]

@markg85, Thank you very much. It's good to know that.