ESP32 Forum

Hi, I'm currently working on my custom made PCB design circuit and the chip mount is ESP32-WROOM-32U. The problem is when i plugged in serial cable it detects serial com port correctly but soon when I try to flash code to esp32U chip it start connecting and then after few seconds it failed saying no serial data received . I have tried manual bootloader , tried to connect capacitor between EN and GND Pin, made GPIO active low when it start connecting but nothing works for me. My question is does the ESP32 fully new chip have write protection enable on it?? if so how can I remove it ?? I have used USB to serial chip CH430 . I have checked serial IC CH340 if it is working properly and send data from serial monitor and analyze on logic analyzer and obviously received correct byte of data I have sent from serial monitor. I'm stuck by this problem I'm not able to flash ESP32 chip even with a simple Blinky example. please if someone can help me in this regard. below here is schematic, error nature, and TX & RX pin response on logic analyzer during code upload.

1. Maybe you should show us more about your schematic related to ESP32 module, or please check if the power supply is enough, when you manually download, could you see "waiting for download" through UART0?
2. From the part you provide, I have to say it seems not correct for CH340G about VCC and V3. From datasheet, when V3 connects a decoupling cap, VCC should be around 5V ( usually connect to VUSB ); when you use 3.3 V VCC, you should connect V3 to VCC.

Hi ESP_LJH, hoping you will be well and good. well I see nothing when trying to enter download mode manually even I don't see my board response on serial monitor when I try to press EN button which shouldn't be the case. Here you can find the whole schematic I have excluded custom design connections. Please if you can review it and tell me the reason what's going wrong with it.

With the board powered on and no button pressed, can you measure the voltage on the RSTB line?

hi , I have just confirmed voltage on RSTB line across resistor R8 and it was showing me 3.2xx with no button pressed, So after measuring it I then pressed RST Button to see its behavior and I just noticed voltage was same still same upon button press.

One more question to ask please if you can answer me ? does the ESP32 fully new SMDs comes with Write protection enable on it ?? if so how can I remove it ? May be I'm unable to flash my chip because of write protection enable on it . please need your comment on it.

No, all ESP32 modules, chips and boards are programmable right off the factory.

I am having the same issue.
Any update on this?