ESP8266 Community Forum

- Sat Nov 05, 2016 12:21 am #57684 Hi,

I have just bought a ESP-12E for my projects. I would like to program firmware into it. I searched in the internet and found this site which suggested I add these resistors to the ESP-12E.

http://ediy.com.my/blog/item/133-upload-sketch-to-the-esp8266-esp-07-esp-12-using-arduino-ide

Are these resistors required ?? I do understand that a program input is required so the reset button will need a pull up, but what about the other resistors and the capacitor are these required as well ??

Also is the programming procedure correct ??

I will be using Arduino IDE for developing on the ESP.

thanks
a

- Sat Nov 05, 2016 4:53 am #57691 Yes, the resistors are required. The pull-up and pull-down settings at power-up determine which boot mode the module will start in (booting from different memory or waiting for program download). The J1 jumper is what selects download mode. If the jumper is present at reset, the module will wait for program download indefinitely. If it is not present it will jump straight into execution of the downloaded program. So put the jumper on and hit reset before attempting to program and remove it for normal run mode.

There is already decoupling on the module, so you can omit the 0.1u cap, but you might want to add a fairly large value electrolytic instead (something between 100 and 470u should do the trick), as a reservoir capacitor to prevent resets when the ESP radio switches to transmit.

IMPORTANT - the ESP8266 is a 3v3 device. You must, as the blog author states, use a 3v3 capable USB adapter -or- a separate 3v3 supply. Using 5v will damage your module.

The blog author also shows the module (and the connections for programming and for his LED circuitry) from the bottom. The side with the metal shield is normally the top, so the connections are flipped left to right if you're looking at the top (and pins 4 and 5 may be different on your module, too). You can go to just about any Aliexpress or Ebay supplier's page for the ESP-12E to find a diagram of the pinouts (from the top) as well as a photograph of the bottom of the board, clearly showing the pinouts (check pins 4 & 5!).

- Sat Nov 05, 2016 8:43 am #57698

Yes, the resistors are required. The pull-up and pull-down settings at power-up determine which boot mode the module will start in (booting from different memory or waiting for program download). The J1 jumper is what selects download mode. If the jumper is present at reset, the module will wait for program download indefinitely. If it is not present it will jump straight into execution of the downloaded program. So put the jumper on and hit reset before attempting to program and remove it for normal run mode.

There is already decoupling on the module, so you can omit the 0.1u cap, but you might want to add a fairly large value electrolytic instead (something between 100 and 470u should do the trick), as a reservoir capacitor to prevent resets when the ESP radio switches to transmit.

IMPORTANT - the ESP8266 is a 3v3 device. You must, as the blog author states, use a 3v3 capable USB adapter -or- a separate 3v3 supply. Using 5v will damage your module.

The blog author also shows the module (and the connections for programming and for his LED circuitry) from the bottom. The side with the metal shield is normally the top, so the connections are flipped left to right if you're looking at the top (and pins 4 and 5 may be different on your module, too). You can go to just about any Aliexpress or Ebay supplier's page for the ESP-12E to find a diagram of the pinouts (from the top) as well as a photograph of the bottom of the board, clearly showing the pinouts (check pins 4 & 5!).

thanks for clearing that up