ESP8266 Community Forum

Hi,
i played around with the ESP12F and NodeMCU for a while now. No problem flashing these two boards, but i also got one that doesnt want to go to flash mode, no matter what i do. I dont even know which model this is. Photo attached, there was originally a shielding on it.

I tried flashing it like my ESP12F

GND->GND
GPIO15->GND
GPIO0->GND

VCC->3.3V
EN->3.3V

but nothing. I even tried putting the pullupresistors between gpio15 and gnd and between en and vcc.
the ESP12-f does boot normal if i disconnect gpio0 and if i connect gpio0 to GND it will go to flash. I can also see it by the led, in flash mode it will just flash once, when booting normal there are at least two flashes. So this other board always flashes the led two times and starts an AP no matter if gpio0 is connected to GND or not. I have read several tutorials about connecting the ESP, some mention GPIO2 and some RST, i tried them all. GPIO2 to high and to low, RST to high and to low, even setting GPIO0 to high. But the only thing that changes is when i set RST ->GND, then the damn thing wont do anything, no blink, no ap but also no flashing. At last chance is resoldered every connection and tested the wiring, everything seems ok.

Do you guys have an idea?

nobody?

The only thing I can think of is that RX is not high. It seems to me that if RX is not high it will not go into program mode. I am about 99% certain.

So check that. No idea if that doesn't work.

Thank you for your input rudy!
I just tested it with my multimeter. RX high means there has to be voltage, wright? if i measure between GND and RX, there is 2.96V. The same Value is measured between GND and VCC. Between GND and TX it is just 2.92V. Im running it on batterys to make sure theres enough current.
Should i measure something else to make sure everything is wired wright?
When the ESP succesfully goes to flash mode, it wouldtn start its AP or would it? Im just asking to rule out wrong settings in the Arduino IDE.

Heres the setup again:
ESP
VCC->VCC
EN->VCC
GND->GND
GPIO15->GND
GPIO0->GND

Programmer
RX->TX ESP
TX->RX ESP
GND->GND ESP