ESP32 Forum

Posted: **Fri Sep 02, 2022 7:58 am**

Hello,

I am trying to flash my first firmware onto my ESP32 S2 FH4 chip, but i cannot connect to the chip. I already tried via USB, CP2102 and usb to ttl, but none of them managed to connect to the chip.

I tested the uploading via usb on the Wemos ESP32 S2 mini and the lilygo ESP32s2 (usb A connector on pin 19 and 20). I managed to recognize the board via USB (get a com port) and upload data, the lilygo board was previously already programed via onboard serial connector.
Sadly the my designed ESP32 S2 FH4 board does not do this, i have checked other schematic and the hardware guidlines and did not find anything that could cause this.

Via USB (pins 19 and 20/ D- and D+)
I tried to put the esp in boot mode (pulling IO0 low on startup) and connecting to it but nothing get recognized.

Via Serial uart0 tx and rx (pins 48 and 49)
Tried connecting to it via serial with a CP2102 and via TTL, but i can't get those to connect to the esp either.

Any suggestions?

Posted: **Fri Sep 02, 2022 12:14 pm**

Agree that the schematic looks good. Some basic debugging:
- Is 3.3V present and stable?
- Can you see some activity on the crystal if you scope it?
- If you reset the chip, can you see serial chatter on the U0TxD pin?

Posted: **Fri Sep 02, 2022 1:26 pm**

ESP_Sprite wrote: ↑
Fri Sep 02, 2022 12:14 pm
Agree that the schematic looks good. Some basic debugging:
- Is 3.3V present and stable?
- Can you see some activity on the crystal if you scope it?
- If you reset the chip, can you see serial chatter on the U0TxD pin?

I see the 3v3 and i don't see it dropping down.
I don't how how to accurately measure the crystal, but i see it go up in voltage on the scope.
When i check the U0TxD i see constant chatter.

: txLine.jpeg (220.15 KiB) Viewed 5203 times

Update:
Managed to capture the sinage wave, so there is activity but the voltage of that does not get higher as 1v

: crystal.jpeg (176.48 KiB) Viewed 5213 times

Posted: **Sat Sep 03, 2022 1:46 am**

That looks good. Just to double-check: you are actually grounding GPIO0 while resetting / powering up the ESP32S2, right? Your board does not have an auto-reset circuit, so you need to set the state of GPIO0 to go into download mode rather than that happening automatically.

Posted: **Sat Sep 03, 2022 8:57 am**

ESP_Sprite wrote: ↑
Sat Sep 03, 2022 1:46 am
That looks good. Just to double-check: you are actually grounding GPIO0 while resetting / powering up the ESP32S2, right? Your board does not have an auto-reset circuit, so you need to set the state of GPIO0 to go into download mode rather than that happening automatically.

I measured the S1 and S2 and both pins go to ground when i press them. So they are working.
What would be the best way to set the GPIO0 pins state?
OR
Should i just build an auto-reset circuit, i searched for it online and found a couple of schematic with npn resistors:
[*]https://forum.micropython.org/viewtopic.php?f=18&t=4966
[*]https://www.eevblog.com/forum/beginners ... t-circuit/

Posted: **Sat Sep 03, 2022 8:59 pm**

I am having the same problem. I've tried both a CP2102 and CH340 UART bridge chips and neither one is getting a response from the ESP32-WROVER. I tried pairing everything down to just 3V3, GND, TX, RX and manual buttons to connect EN to ground for reset and GPIO 0 to ground for the programming boot option. No matter what I try, there is data transmitted from the UART bridge and there is no reply from the ESP32-WROVER. I am completely stumped. I've even tried different ESP32-WROVER modules straight from the package and the issue persists. I cannot get the chip to respond. Any advice would be greatly appreciated.

Posted: **Mon Sep 05, 2022 6:36 am**

Update:
I got the some connection to the esp, i now get the response

Code: Select all

invalid header: 0xffffffff

So now got something to start troubleshooting from.

After programming
I tried programming, with putting the esp32s2 in boot mode and via the auto reset circuit.
With both variants my esp gets into a boot loop, where it does not exit from. There is nothing different connected to the esp as to the experimental version i use.

(PCB #1)

Code: Select all

ESP-ROM:esp32s2-rc4-20191025
Build:Oct 25 2019
rst:0x1 (POWERON),boot:0xa (SPI_FAST_FLASH_BOOT)
SPIWP:0xee
mode:DIO, clock div:1
load:0x3ffe6100,len:0x524
load:0x4004c000,len:0xa70
load:0x40050000,len:0x292c
SHA-256 comparison failed:
Calculated: 8dce998efc3eb6dc43f3799a489dbcfbd5ada9828beadf71017c05c4a8d32bc3
Expected: ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
Attempting to boot anyway...
entry 0x4004c18c

I also had the sha comparison failed on other esp32 s2 board, this is caused by the arduino ide i think but not an issue on the other boards.

This is what it should have been:

Code: Select all

ESP-ROM:esp32s2-rc4-20191025
Build:Oct 25 2019
rst:0x1 (POWERON),boot:0x8 (SPI_FAST_FLASH_BOOT)
SPIWP:0xee
mode:DIO, clock div:1
load:0x3ffe6100,len:0x524
load:0x4004c000,len:0xa70
load:0x40050000,len:0x292c
SHA-256 comparison failed:
Calculated: 8dce998efc3eb6dc43f3799a489dbcfbd5ada9828beadf71017c05c4a8d32bc3
Expected: ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
Attempting to boot anyway...
entry 0x4004c18c

** Trying to starting ethernet**
 initial STATIC assigned IP: 192.168.1.2

Note:
I am programming with the arduino ide v2.0 with esptool v3.3

Posted: **Mon Sep 05, 2022 9:59 am**

I tried to upload a simple blink sketch with the arduino ide v2 and v1.8.19 and still resets the esp.
Even just trying to use the serial port and to that it will just reboot.

Could it be anything with the boot configuration off the IO45 and IO46 pins be that the program keeps crashing? i don't have any external flash or psram chips connected??

Posted: **Tue Sep 06, 2022 1:58 am**

GPIO45 could be an issue if you have it connected to something. According to your schematic you have it NC, though.

Posted: **Tue Sep 06, 2022 6:33 am**

ESP_Sprite wrote: ↑
Tue Sep 06, 2022 1:58 am
GPIO45 could be an issue if you have it connected to something. According to your schematic you have it NC, though.

What would be the best solution?

The code is not the problem, sinds a basic blink program does not work and still restarts.

On manual restart it happens after 4 seconds and after that within 3 seconds between every reset.

ESP32 Forum

ESP32 S2 FH4 First factory upload

ESP32 S2 FH4 First factory upload

Re: ESP32 S2 FH4 First factory upload

Re: ESP32 S2 FH4 First factory upload

Re: ESP32 S2 FH4 First factory upload

Re: ESP32 S2 FH4 First factory upload

Re: ESP32 S2 FH4 First factory upload

Re: ESP32 S2 FH4 First factory upload

Re: ESP32 S2 FH4 First factory upload

Re: ESP32 S2 FH4 First factory upload

Re: ESP32 S2 FH4 First factory upload