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Trying to understand when to use the flash button?  

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garnold
(@garnold)
Trusted Member
Joined: 12 months ago
Posts: 68
2019-06-20 11:50 pm  

I'm trying to understand when I need to use the flash button on my NodeMCU. I'm reading things like I need to push this to flash the board but I never seem to need to. Is this for when I push code from the Arduino IDE? Is this for when I have something connected to a pin on the board? I'm also trying to understand this idea of having to have pins High or Low to flash the board. Is there a Drone Bot Workshop video that explains pins and some of their use cases? When I look at the pin out of a board I see lots of descriptions for the same pin and when I try to figure out if I can use a GPIO for something I'm reading "Well sometimes if you turn this off or set this to low or DON'T CONNECT something to the pin on boot". Please help a noob out over here 🙂


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Robo Pi
(@robo-pi)
Robotics Engineer Moderator
Joined: 12 months ago
Posts: 1757
2019-06-21 12:45 am  

Hi, I found the following information on the web:

To enable ESP8266 firmware flashing GPIO0 pin must be pulled low before the device is reset. Conversely, for a normal boot, GPIO0 must be pulled high or floating. If you have a NodeMCU dev kit(ESP 12) then you don't need to do anything, as the USB connection can pull GPIO0 low automatically while flashing.

I've been using just the ESP 8266-01 module for my projects.  I need to ground the GPIO0 pin to program it.   I write my own firmware using the Arduino IDE.   However, I'm also programming it using a serial connection.

According to the above information if you are connected to your  NodeMCU using a USB connected to your computer than this is taken care of for you so you shouldn't need to worry about having to ground the GPIO pin.

DroneBot Workshop Robotics Engineer
James


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garnold
(@garnold)
Trusted Member
Joined: 12 months ago
Posts: 68
2019-06-21 4:21 am  

Thank you for this. So when would I need to use the flash button on this board? 


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Robo Pi
(@robo-pi)
Robotics Engineer Moderator
Joined: 12 months ago
Posts: 1757
2019-06-21 4:41 am  
Posted by: garnold

Thank you for this. So when would I need to use the flash button on this board? 

I'm not certain, but I would think that you would only need to use it if you are programming it using a USB-to-Serial adapter instead of a USB connection directly.  The USB-to-Serial connects to the Rx and Tx pins of the ESP 8266 chip.  

At least this is my understanding.  I've never used the NodeMCU.   I just use the ESP 8266-o1 module directly.    So I have to use the USB-to-Serial method since there is no USB port on the o1 module.

DroneBot Workshop Robotics Engineer
James


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