Thanks for your answer.
My main problem - no RS communication when i use SparkFun(master) + NodeMCU(slave).
The problem is with the NodeMCU(I checked on 2 copies).
With the above code NodeMCU not blinking(led off).
Once, for several power on, the transmission starts (and works - I tested with led code / with my project code). In this state led blinking.
Second question.
SparkFun(1) +ESP32-DevKitC (2) - transmission is ok. But there is on strange case . When i reset(push button on board) slave(sparkfun) sometimes transmission stop working(mayby ~ 025% of cases).
I will check what happens when I stop sending data from the master, reset the slave, and then start sending data. Maybe this is a solution to the secondary, side question.
Add:
OK. All time I use ArduinoIDE 1.8.4, with arduino-esp32 library:
https://github.com/espressif/arduino-esp32/tree/master/librariesBoard: "Node32s" // or NodeMCU-32s
Flash Frequency: "80 MHz"
Upload Speed: "115200"
and this not work correctly.
I add:
#include <dummy.h>
// dont know its necessary, never use this before; it's Esp32 library
and delay(2000) in setup(on master).
Now 8 out of 10 attempts its ok.
But how make 10/10?
To upload code i need unplug rx cable and press buttons enable + reset(download mode) to upload code.
But it's not always work(few tries).With other board this problem occurs less frequently.
This boards have a 3x UART. How to use it simply?
If i use only 1 UART, mayby change pinout in library?
When i plugin usb, arduino sends/receive data from PC only on 1 UART (Rx/Tx 1/3pins)?
Mayby if i connect boards with other UART, power on/connect to PC dont generates data on others UARTS and all works fine?