I have (many) ESP8266 dev boards (most WeMos and some LoLin). I usually connect them with ESPlorer via usb cable. I use Ubuntu 14.04 on a desktop and I see device regularly on /dev/ttyUSB0. I also have my own version of NodeMCU vers. 1.5.1 compiled with my personal configuration (just add some libraries like http and ow...). No problem with this setup and everything is working smoothly.
Now I want my production devices to be based on ESP-12E with NO micro USB and therefore I need to upload my NodeMCU and my Lua programs via UART. I made some trials with WeMos and trying to programming it via UART and not via microUSB without success.
I used a USB to TTL devices from Aliexpress. I just made the obvious connections from this device to dev board (see picture):
GND – GND
TX – RX
RX – TX
From my desktop I can see /devv/ttyUSB1 (the USB to TTL device) but I do not have any answer from ESP. Surely I miss something but don’t know what. Therefore basic questions:
1. Can both serial lines work with a dev board ESP (i.e. a board with micro USB connector)? NodeMCU and basic firmware will reply to both or thet are exclusive? If I open with ESPlorer /dev/ttyUSB0 it responds though. Still no answers if I open /dev/ttyUSB1 (the device connected to USB-to-TTL)
2. NodeMCU supports AT commands? Maybe is the same problem above but I really wonder if NodeMCU has still support for AT and where does it reply to AT commands (which tty uses).
This is the picture of the connection. Hope it help for someone willing to reply
Thanks in advance