I have an Uno that talks to 3 other Unos via Serial and softserial. I am not looking for a practical solution, just an explanation why the phenoma is occuring. Yes I know I2C will work as will SPI.
My "center" uno talks to one of the 3 others via Serial no problem. It also talks to one of the SoftSerial Unos but not the second. I have played with the wires and code and it seems that I can only have one and only one SoftSerial port pair (Rx/Tx) at a time. I have not seen this limitation anyplace in the documentation.
Has anyone else ran into this issue?
Thank you very much.
SoftwareSerial is a very poor substitute for HardwareSerial and only one instance can work at any one time. You could try AltSoftSerial or NeoSWSerial. But really if you need more than one extra serial port you should use a Mega which has 3 spare HardwareSerial ports.
...R
Serial Input Basics
Robin2 : yea.. I seem to be leaning in that direction. Thanks you
That is because the TX of the other two UNOs are tied in parallel, if I understand what you have. Each TX will hold the line HIGH until it is ready to send a start bit, which is LOW. That can't be done if the other device it holding the same line HIGH!!!
Paul