ESP8266 Community Forum

- Thu Jul 28, 2016 12:57 pm #51656 Hi,

I've made a little breakout board (see attachment for circuit diagram and picture) to add a header for a FTDI adapter. I added two voltage divider because the FTDI does not support 3.3V on RX/TX.
Unfortunately, when connecting Vcc1, the blue LED stays on and the board does not boot. However, the ESP-01 does work. When connecting a power supply to GND/PD_CH+V it boots and connects to WLAN.

Do I miss something in regards to electronic circuits (e.g. wrong resistors)? Because I've checked the soldering twice and found no short or the like.
Would be great, if someone has an idea, where to look or what else to test. Or does anybody know when the blue LED becomes "always on"?
Note that the DS18B20 (and R1) are not connected to the board. That's just an usage example.

Thanks & best!

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- Sun Jul 31, 2016 4:24 pm #51861 You cannot use a voltage divider to power an ESP.

- Mon Aug 01, 2016 1:57 am #51872 The FTDI chip cannot provide enough current for the ESP8266. Use a 3.3V voltage regulator fed by the USB 5V capable of sourcing 500 mA or more.

- Mon Aug 01, 2016 2:27 am #51874 1) your voltage dividers have too low impedance.
2) you only need voltage divider for FTDI-TX to ESP-RX
(ESP-TX is only 3.3V, so nothing to divide, doesn't work "upwards" to provide 5V to FTDI-RX!)
Don't forget pullups (typ. 10k) on gpio0, gpio2, rst and EN

If you want to power ESP from USB/serial converter, buy one with SiliconLabs CP210x and put at least 470µ close to ESP-board