[NodeMCU] HowTo connect the NodeMCU to the PC via PuTTY?

All ESP8266 boards running MicroPython.
Official boards are the Adafruit Huzzah and Feather boards.
Target audience: MicroPython users with an ESP8266 board.
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ZKDMun
Posts: 42
Joined: Thu Nov 24, 2016 2:34 pm
Location: Hamburg

[NodeMCU] HowTo connect the NodeMCU to the PC via PuTTY?

Post by ZKDMun » Thu Nov 24, 2016 4:23 pm

I'm a absolute beginner with microcontrollers - the ESP8266 is my first attempt to walk :/

Can anyone explain me how I can connect the NodeMCU with my PC successfully and how I can open the so-called REPL?

At this time I was able to flash MicroPython successfully (I think so, because the blue LED was on).

(I am using Windows 7.)

At the beginning I erase the flash via cmd.exe:
esptool.py --port COM7 erase_flash
(Python and esptool is installed on my pc)

After that I flash MicroPython on my NodeMCU via:
esptool.py --port COM7 --baud 56700 write_flash --flash_size=detect -fm dio 0 esp8266-20161017-v1.8.5.bin
and after a few seconds MicroPython I always get a message that MicroPython is flashed ("Writing 565248 0x0.... 565248 (100%) ...")
The LED on the NodeMCU is now on!

(I use the v1.8.5 because I read before this thread:
http://forum.micropython.org/viewtopic.php?f=16&t=2492
but with v1.8.6 and this solution the problem was the same... so I thought it is better to downgrade :/)

But my problem is:
I can not open the REPL (is it called REPL?)
I use putty_0.67, but every time I have tried to open the REPL via PuTTY there was no success. I have tried different speeds, 115200, 56700, 74800, 9600.... but everytime I only see some unreadable literals... sometime PuTTY told me, that it can not read "main.py".

How can I solve this problem?
Is it a defect of the NodeMCU?

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Roberthh
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Location: Rhineland, Europe

Re: [NodeMCU] HowTo connect the NodeMCU to the PC via PuTTY?

Post by Roberthh » Thu Nov 24, 2016 5:09 pm

The right speed is 115200.
The message "cannor read main.py" comes from the ESP8266, not from puTTY. So if you see that, at least the connection with puTTY is right. Please disable any flow control at puTTY.
If puTTY is connected and you press reset on the board, you should see first a flush of random characters, but then the Micropython boot message.
In principle the order: a) erase flash and b) load micropython is right. But there weer some complaints that erasing did not work, and then the reinialization of MicroPython fails. See also this thread: viewtopic.php?f=16&t=2675

ZKDMun
Posts: 42
Joined: Thu Nov 24, 2016 2:34 pm
Location: Hamburg

Re: [NodeMCU] HowTo connect the NodeMCU to the PC via PuTTY?

Post by ZKDMun » Thu Nov 24, 2016 6:07 pm

ok, thanks for this background information. :)

How I can disable the flow control? I have tried it via "connection -> Serial" and the settings:
Serial line to connect to: COM7
Speed(baud): 115200
Data bits: 8
Stop bits: 1
Parity: None
Flow Control: None

But it doesn't work?
After every reset of the NodeMCU I get this message:
http://oi68.tinypic.com/2kh94w.jpg
(btw: is there no way to upload pictures on this community? :/)
But I am not able to type any commands? :(

ZKDMun
Posts: 42
Joined: Thu Nov 24, 2016 2:34 pm
Location: Hamburg

Re: [NodeMCU] HowTo connect the NodeMCU to the PC via PuTTY?

Post by ZKDMun » Thu Nov 24, 2016 9:26 pm

It works!

After waiting a few seconds more I was able to use the REPL :)
Thank you very much ;)

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