Node mcu to arduino serial communication

[tapu]

Dear All ,
I want to transfer integers 1 to 9999 from node mcu esp8266 to arduino nano by using serial port and displaying this number on 4 digit 7 segment display.as i send numbers then it is successfull till 0 to 255.after 255 it again start from 0 .that means i cant send number like 256 and more.pls guide.
Thanks
Tepu

 

[betwixt]

There are many ways to do this!

0 to 255 fits in one byte so you need to split the 1 to 9999 into smaller parts.

You have to decide which end does the work, you can send four digits from the esp8266 '0001' to '9999' or you can send two bytes 0x0001 to 0x270F then convert them back to decimal at the nano end.

You also have to decide how to 'frame' the data, just sending digits will not work because there is nothing to say which digit is which. For example sending 1234 might display as 2341 because it didn't recognize that the '1' was the first digit.

I am not sure what your application is but I would suggest you use a number out of range as a 'reset' so it knows the next digit is the first to display.

Please explain what your application does or whether it is just an experiment so we can be more helpful.

Brian.

 

[danadakk]

A discussion of protocol and interface :

https://smartfarm.rmuti.net/download/14serialcommunication.pdf

Search on youtube for "esp8266 to arduino serial link", quite a few videos.

As betwixt points out a UART sends data, byte at a time, and the UART does
not know what the bytes are or their order, thats up to you to frame and
decode.


Regards, Dana.

 

[KlausST]

Hi,

I agree to the above.

Just to make it clear: This problem has nothing to do with
* ESPxxx hardware
* Arduino hardware
* Arduino IDE

--> it is a protocol problem.

And solved since 50+ years. Discussed very often (billion times), many different solutions ...

Klaus