ESP32-DevKitC-32D Upload to Flash Problems

[rmetzner49]

I recently purchased this board from Mouser because I wanted a robust unit to develop with. I have also in past purchased other versions of an ESP32-Dev board from Ebay vendors. I also have an Adafruit ESP32 Feather and am using Arduino 1.83.

Up until this recent purchase I've had no trouble uploading sketches with any other versions, but this new one fails in terms of "no packet header" being supplied. I've looked at the Reset Circuit with respect to DSR and DSD with the EN line and all seems appropriate. I've even tried to manually toggle the RESET and BOOT buttons to no avail. The COM port is COM57 and Device Manager reports it working.

I would like to think I didn't buy a $10 "brick" from Mouser. Any ideas?

Thanks.
Bob M.

[kolban]

If it were me, what I'd suggest is attaching a serial terminal to the board and seeing what it looks like when it boots. See then if it can be placed into flash mode with the buttons. Maybe post the logs from the console output showing what you see.

[rmetzner49]

Thanks, I'll try that when I get some more time. In the meantime, I've ordered another one from Ebay, Ezsbc which I had before and it worked. I can see myself spending hours on debugging this.

By the way, I enjoyed your PWM object and used it for my son's Wheelchair Controller; it needed RC-Servo type outputs and it worked perfectly for that. Ended up using 14-bit precision to get good resolution but I only needed 50Hz for the Servo.

Bob M.

[ESP_krzychb]

Hi rmetzner49,

I am wondering what USB-to-serial chip is installed on boards that are working and what on the new ESP32-DevKitC-32D broad? Do all of them have CP2102 or maybe the new one has CP2102N?

[rmetzner49]

According to the schematic, it has the CP2102N-A01-GQFN28. As I said in the O.P., Windows recognizes it as COM57.

All this is supported at http://esp-idf.readthedocs.io/en/latest ... vkitc.html but that doesn't get me any closer to identifying the problem. I was just looking to see if others who purchased this board had problems too.

I can switch from Board to Board, between IT and an Adafruit Feather and can change board type and upload to the Feather. Steer clear of that Feather unless you specifically want the Lithium Charging on board. They scrambled all the rest of the I/O terribly. So with that board, if you're trying to run I2C or SPI it will be a challenge. I sorted out I2C because I had to.

The other configuration I have no trouble uploading to is my proto board with an ESP32 WROOM on it. There, I've used the FTDI231XS only because it comes in a SOP-20 package.

Bob M.

[ESP_Angus]

Hi Bob,

We've been talking to SiLabs about a problem with the CP2102N where it permanently stops sending any data after a port is closed and reopened, requiring a power cycle before it comes good again. If you unplug and replug the DevKitC, does it work the next time you try to upload to it?

If it doesn't respond under this circumstance, similar to kolban's suggestion, try opening a serial terminal program at 115200bps and then press and release the EN button to reset the chip, and see if anything appears at all. Maybe power cycle the DevKitC once more before doing this.

If you get nothing in the serial terminal under this circumstance, you probably have faulty hardware (the only other possibility I can think of is wrong COM port or some kind of driver problem, and these seem unlikely).


Angus

[rmetzner49]

Hi Angus;

I think you are on to something there. On a fresh boot, with Arduino pointing at COM57 I get the traditional diagnostics correctly. Then when trying to upload a sketch, I get "A fatal error occurred: Failed to connect to ESP32: Timed out waiting for packet header
Board at COM57 is not available".

We both know that the ESP32 gets reset during the upload operation because of the cross-coupled NPN transistors connected to DSR/DTR but then if it's the problem with the CP2102N as you say, it never allows the ESP32 to respond. I wonder if Espressif thinks this is an acceptable way to sell a board with problems. Sequencing the EN and BOOT buttons every time you want to upload is an undesirable PAIN.

Manually toggling the buttons isn't going to help much if DSR/DTR resets it during the upload. I wonder if it's worthwhile trying to jumper the /RST pin on the 2102 to EN? Do you know if grounding /RST gets the 2102 out of latchup?

Thanks.
Bob Metzner

[rmetzner49]

Come to think of it, messing with the RST line on the 2102 won't work since that's where DSR/DTR originate.

Bob M.

[rmetzner49]

Kolban has done it again. I can successfully upload IF I hold the BOOT button down until just before the bar graph is finished. I guess Arduino cycles DSR/DTR at that point and the button overrides those signals.

I should also note that once a sketch is uploaded, pressing RESET, then holding BOOT while releasing RESET gets you into a "waiting for download" mode. No sequence gets you back to the original diagnostic screen. Obviously NOT holding Reset runs your application.

Thanks.
Bob Metzner

[michprev]

We've been talking to SiLabs about a problem with the CP2102N where it permanently stops sending any data after a port is closed and reopened, requiring a power cycle before it comes good again.

Hi Angus,
any new info about that? I am choosing between CP2102 and CP2102N in my PCB design. It would be nice to know that there are some issues with CP2102N / that it should be connected to ESP32 differently than in ESP32 DevKitC V4 design.