ESP32 Forum

I've been struggling to understand why my flashing circuit isn't working. It's a copy of the image below, but without the LED, and using a real 3.3V power supply.



I know the module works, because I have successfully programmed it using a USB programmer I bought, and I see all the normal boot messages in a serial console at 115200 baud.

Here's the output of tying EN high and GPIO0 low:

rst:0x1 (POWERON_RESET),boot:0x3 (DOWNLOAD_BOOT(UART0/UART1/SDIO_REI_REO_V2))
waiting for download

Yet I can't reach the module with idf.py, despite being able to communicate serially (as per ability to receive above message):

esptool.py -p /dev/ttyUSB0 -b 115200 --after hard_reset write_flash --flash_mode dio --flash_freq 40m --flash_size 2MB 0x1000 bootloader/bootloader.bin 0x8000 partition_table/partition-table.bin 0x10000 i2c-example.bin
esptool.py v2.6
Serial port /dev/ttyUSB0
Connecting........_____....._____....._____....._____....._____....._____....._____

A fatal error occurred: Failed to connect to Espressif device: Timed out waiting for packet header
esptool.py failed with exit code 2

I get this message regardless of if I leave GPIO0 low or floating after the module enters download mode.

I know that idf.py is working, because I can flash to a couple of development boards that integrate their own programming circuitry. I have also verified the solder connections on the breakout board (which are also provably working as serial communication works fine).

What's wrong? I found an identical problem here, but the thread author never seemed to resolve the issue after he opted to use a development board with integrated programmer instead.

Where is the image?

mikemoy wrote:Where is the image?

Do you mean the image of the circuit? If it's not displaying inline, it's available here.

That link does not work

mikemoy wrote:That link does not work

Really? You must be getting rendered a different page than me; maybe forum moderation rules don't permit links unless approved and the Espressif team are absent during Chinese New Year. The link is:

https://www.14core.com/wp-content/uploa ... iagram.jpg

Same thing here is the screen shot. You can just drag your .jpg file into the post, then click place inline. That works for me.

Clicking the link directly didn't work. Right-clicking and "open in new private/incognito" window worked for me.

Oh, I didn't realize the CDN wasn't letting you through. I've attached the circuit diagram to this post (so it's uploaded to the Espressif server). You should now be able to see it.

Solved. I ran some integrity test on all the pins, and there's an internal short between two of them. I found a fresh, never-used module and it flashes OK.

Hey,

can you please confirm and guide me on how did you conduct the "Pin Integrity Test". Is it some kind of script from idftoolset that I am unaware of?

Thanks