Use this forum to chat about hardware specific topics for the ESP8266 (peripherals, memory, clocks, JTAG, programming)

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By Nico van der Dussen
#21732 Hi,

I'm new to the ESP8266

I want to use it with the Arduino IDE.

I have a CP2102 and a separate 3.3V power source (I tested - can deliver 500mA without voltage dropping)

Can I connect the CP2102 TX/RX/RST/DTR pins straight to the ESP8266 or must I use a 5V/3.3V level shifter?

I'm configuring the hardware according to the Minimal hardware Setup for Bootloading and usage on

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By Stoney
#21791 I usually use a CP2102 board .. it has a 5v link you can cut and then solder across to get 3.3v on the vcc pin but that is all it changes .. the actual data from the CP2102 on mine is always 3.3v. I expect all CP2102 are the same, the 5v is simply straight USB 5v but the chip uses an internal 3.3v regulator and I guess 3.3v for the output drivers as well.

also .. according to element14 at

"ESP8266 happily accepts data at 5 V (datasheet says inputs are 5V tolerant). ESP8266 power supply remains at 3.3 Volts."

So would say its all good..
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By Stoney
#21793 forgot to mention .. I have also used some PL2303 modules to program mine with a few times, not seen any issues..
they are 5v output on the data. only used RX and TX though .. no RTS and CTS etc on them.

and .. I have tried the RTS/CTS method and it did not work very well for me, it did work a couple of times but not always I think. I either use ESP01 on a breadboard with a switch on GPIO-0 or ESP12e on a carrier board that has a reset and boot switch.