ESP8266 Community Forum

Hello

I'm a newbie. I have bought an ESP8266-01 to play with, I also bought a USB programmer with chip CH340 (?) on it. I also soldered a reset button on to it so that I'm amble to flash the ESP-01 with my own firmware.

I also have a 240VAC to3.3VDC PSU. I am trying to connect the ESP8266 to the 3.3VDC PSU and I can't get it working. I have read through the first 5 pages of these forums and nowhere could I find the instructions on how to connect the ESP8266 to a 3.3VDC supply.

I made my own assumptions and connected the ESP8266 VCC to 3.3VDC and the GNC pin to GND on the PSU. I have connected CH_PD to a 1K resistor that connects to 3.3VDC.

What other connections do I need?

When running my firmware through the USB CH340 the ESP-01 works as expected. Lights blink as expected, WiFi is connected as expected. I checked the voltages on all 8 pins, all are at 3.3V except for GND, TX and RX. Tx is at 0, Rx at 5V. (I thought the maximum should be 3.3V but the USB programmer is making the Rx at 5V). But everything is working when using this USB CH340 programmer.

When I connected it to my own 3.3VDC PSU, the ESP-01 isn't responding as expected.
VCC is 3.28V, RST is 3.25, CH_PD is 3.30, Tx is 3.28, Rx is 3.05, GPIO0 is 0.6, GPIO2 is 3.25, GND is 0.

On the USB CH340 (working as expected)
VCC is 3.33V, RST is 3.30, CH_PD is 3.33, Tx is 3.33, Rx is 5.10, GPIO0 is 3.29, GPIO2 is 3.30, GND is 0.

So the difference between using the USB adapter and using my own PSU is at the Rx and GPIO0 pins.

Am I looking the wrong way?

Perhaps I should be pulling up/down some pins when using my own PSU?

p/s how do I know if my ESP-01 is in boot mode or operation mode without using AT commands or UART?

Thanks for reading, I appreciate any feedback.

Hello. I have this fixed and I don't understand why.

Apparently most of the diagrams show that GPIO0 needs to be pulled to 3.3V. And this is what I have done.

But once I take out the GPIO0 pin and let it float, the ESP-01 boots up the program fine and all is well.

I don't understand it at all.

So you see the difference...gpio 0 should be high ( 3.3v ) on reset/boot otherwise it enters flash upload mode.
Try to pull Gpio 0 high before firing up esp8266 and see what happens.

Also esp8266 needs at least 500milli amps.

I have never had to manually pull up gpio 0, but maybe your sketch is making gpio 0 go low? Also, 5v on RX? Is kind of strange. Are you sure it is not TX?

(Edit: wrote high instead of low- corrected)

Removing the pullup may work sometimes, but it will not work 100%, there might be a very weak pull up internally... ALWAYS pull GPIO0 up! **ALWAYS**

RichardS