ESP32 Forum

Posted: **Wed Mar 06, 2024 5:13 pm**

Hi there,

I'm seeking assistance with my DIY smartwatch project. I've designed a custom board utilizing an ESP32S3 and carefully followed the hardware design guidelines,but it's my first time designing a custom board for ESP32. Upon assembly and testing, I've encountered issues with its functionality. Below is the serial log:

Code: Select all

ESP-ROM:esp3ESP-ROM⸮ESP-ROM⸮ESP-ROM⸮ESP-⸮ESP-ROM:⸮ESP-R⸮ESP-ROM:ESP-ROM:e⸮ESP-ROM:e⸮ESP-ROM:⸮ESP-ROM:esp32s3-20210327
23:26:31.244 -> ESP-ROM:esp32s3-20210327
23:26:31.244 -> Build:Mar 27 2021
23:26:31.244 -> rst:0x1 (POWERON),b⸮ESP-ROM:esp32s3-20210327
23:26:31.291 -> Build:Mar 27 2021
23:26:31.291 -> rst:0x1 (POWERON),boot:0xa (SPI_FAST_FLASH_BOOT)
23:26:31.291 -> invalid header: 0xffffff7f
23:26:31.291 -> invalid header: 0xffffff7f
...
23:26:31.525 -> invalid header: 0xffffff7f
23:26:31.525 -> invalid header: 0xffffff7f
23:26:31.525 -> invalid header: 0xffffff7f
23:26:31.525 -> invalid header: 0xffffff7f
23:26:31.525 -> invalid header: 0xffffff7f
23:26:31.525 -> invalid header: 0xffffff7f
23:26:31.525 -> invalid header: 0xffffff7f
23:26:31.525 -> invalid header: 0xffffff7f
23:26:31.525 -> inva⸮ESP-ROM:esp32s3-2021⸮ESP-ROM:esp32s3-20210327
23:26:31.995 -> Build:Mar 27 2021
23:26:31.995 -> rst:0x1 (POWERON),boot:0xa (SPI_FAST_FLASH_BOOT)
23:26:31.995 -> invalid header: 0xffffff7f
23:26:31.995 -> invalid header: 0xffffff7f
23:26:31.995 -> invalid header: 0xffffff7f
23:26:31.995 -> invalid header: 0xffffff7f
23:26:31.995 -> invalid header: 0xffffff7f
...

The first line corresponds to when I repeatedly press the reset button on the PCB. Subsequent lines occur when I short the EN pin with 3v3, resulting in a continuous repetition of "invalid header: 0xffffff7f". I've found a similar issue reported in this post: https://esp32.com/viewtopic.php?p=127694#p127694. However, despite having asked him, I haven't received a response yet.

Here's the schematic for reference:

This project marks my first serious endeavor, and I'm eager to see it through to completion. Any guidance or assistance provided would be highly appreciated.

Thank you kindly.

Posted: **Thu Mar 07, 2024 3:08 am**

Can you succesfully flash the chip/board? Also, just to be sure, you don't happen to have used an ESP32-S3 which already has internal flash?

Posted: **Thu Mar 07, 2024 5:49 am**

ESP_Sprite wrote: ↑
Thu Mar 07, 2024 3:08 am
Can you succesfully flash the chip/board? Also, just to be sure, you don't happen to have used an ESP32-S3 which already has internal flash?

Thank you for your reply. I cannot flash the chip/board; the error that occurs is similar to the one mentioned in the post. I used ESP32-S3R8 for this board, so I'm pretty sure it doesn't have internal flash.

Posted: **Thu Mar 07, 2024 8:49 am**

Can you try to run
esptool.py -p your_com_port read_flash_status
and post the output here?

Posted: **Thu Mar 07, 2024 5:15 pm**

Unfortunately, the USB to Serial CP2102 I have now seems unable to transmit data via the module's TX, only to receive data via the module's RX. The boot log I posted can only be viewed from the Arduino serial monitor; I cannot get the onboard RX to work. So first, I want to ask if you have any ideas to solve the problem at https://esp32.com/viewtopic.php?p=127694#p127694.

Posted: **Fri Mar 08, 2024 4:05 am**

I'd suggest to get serial working first then. You need that anyway and it's pretty much needed if you want to debug this issue.

Posted: **Thu Mar 14, 2024 2:12 pm**

The error message "invalid header: 0xffffff7f" suggests a problem with the initial boot process, possibly indicating a corrupted or missing bootloader. Please check the connections on your custom board to ensure they match the ESP32S3 hardware design guidelines. Also, check if there is any short circuit or broken trace. By any chance if you consider re-printing and re-assembling the PCB from a dependable manufacturer, you can choose (redacted). (redacted URL)
(edited by moderator)

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