ESP32 Forum

Posted: **Tue Oct 16, 2018 8:58 pm**

Hi. I just built a board for the WROVER, but I can't get it to flash. I'm using the CP2102 USB to UART chip, which seems to be working fine - recognized as a COM port on Windows and TTY on Mac. Arduino and IDF seem to recognize the chip:

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Sketch uses 223488 bytes (17%) of program storage space. Maximum is 1310720 bytes.
Global variables use 14648 bytes (4%) of dynamic memory, leaving 313032 bytes for local variables. Maximum is 327680 bytes.
esptool.py v2.3.1
Connecting........_
Chip is ESP32D0WDQ6 (revision (unknown 0xe))
Features: WiFi, BT, Dual Core, VRef calibration in efuse
Uploading stub...
Running stub...
Stub running...
Changing baud rate to 921600
Changed.
Configuring flash size...
Warning: Could not auto-detect Flash size (FlashID=0x0, SizeID=0x0), defaulting to 4MB
Compressed 8192 bytes to 47...

Writing at 0x0000e000... (100 %)
Wrote 8192 bytes (47 compressed) at 0x0000e000 in 0.0 seconds...

A fatal error occurred: Timed out waiting for packet header
A fatal error occurred: Timed out waiting for packet header

...but then fail waiting for the packet header (same message in Arduino and the IDF). When I hit the reset button, I get:

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rst:0x10 (RTCWDT_RTC_RESET),boot:0x33 (SPI_FAST_FLASH_BOOT)
flash read err, 1000
ets_main.c 371 
ets Jun  8 2016 00:22:57

over and over again.

I followed the schematic for the Lyra board in terms of SD card setup, USB to UART, and reset circuitry. My schematic is here:

As I mentioned, I used the same pinout configuration used on the Lyra. I'm concerned that some of the pins, especially IO0, which I'm using for my audio codec MCLK, is needed in the boot process. I guess I'm not perfectly clear on what needs to be pulled up or down during boot, and how that effects those pins after boot.

Any help with this would be greatly appreciated! Thanks!

Posted: **Wed Oct 17, 2018 2:23 am**

czyskows wrote: I followed the schematic for the Lyra board in terms of SD card setup, USB to UART, and reset circuitry.

Your image is too small to read easily but it looks like you didn't follow the Lyra schematic because you put the SD card connected to the flash pins instead of the hs2 pins.

Posted: **Wed Oct 17, 2018 7:26 pm**

Quite right -- Every other schematic I found used the SD flash pins instead of the hs2 pins, so I opted to do that. The problem ended up being electrical -- the diodes that are shown on the schematic by the SD card were the problem. They appear to be totally unnecessary. When I took them off, everything worked, so I assume one of the flash pins was getting pulled down by one of those. Anyway, solved.

Posted: **Thu Oct 18, 2018 12:49 am**

The diodes are an ESD protection chip. Your next problem will be how to use the sd card in parallel with the flash because it is not supported afaik.

ESP32 Forum

WROVER Module Flashing Problem

WROVER Module Flashing Problem

Re: WROVER Module Flashing Problem

Re: WROVER Module Flashing Problem

Re: WROVER Module Flashing Problem