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By anandhu08
#68816 I am a beginner. I have used the Arduino 1.8.3 IDE for programming my ESP-12 module. I made the connection as shown below:
VCC ---------> 3.3V
TXD0 ---------> Rx of FTDI
RXD0 ---------> Tx of FTDI
GPIO0 ---------> pulled up through 1K resistor
GPIO2 ---------> pulled up through 10K
GPIO15 ---------> pulled down through 10K
RST ---------> pulled up through 10K
EN ---------> pulled up through 10K
Two push buttons are used to pull down RST and GPIO0.
I programmed the basic led blinking program (BUILTINLED) and is working fine. The pin that is blinking now is GPIO1(TXD0). It is working fine. But I cannot reprogram the module.
If I connect the TXD0 to the Rx of serial to usb converter the module itself is not working. ie, if I press the RST button without connecting the TXD0 the module is getting restet (on board blue led blinks), the voltage level at TXD0 is 3.3V. But when I press the RST button after connecting the TXD0, the module is not responding and the voltage level at TXD0 pin drops to about 1.2V.

Please help and thanks in advance.
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By philbowles
#68997 Have a read of this:

Code: Select allhttps://github.com/espressif/esptool/wiki/ESP8266-Boot-Mode-Selection


GPIO0 must be LOW (at power-up time) for UART programming.

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