Software Serial doesn't like itself.

Projects Programming
1

I am developing a system with three Nanos. One is for user interface, one sends/receives on a 433 Mhz. transceiver, and one maintains an internet connection. I intended to set up two software serial links from the user interface to the other Nanos. I wired these up, tested them electrically, and then found that I just could not get data from the network Nano to the user interface Nano. After lots of "secular prayer" and tearing of hair, I discovered that my user interface nano would only communicate if just one SW serial link was initialized, not both.

I understand that the receive lines for a SW serial link apparently respond to an interrupt on the receive line when data is incoming. But if the two receive lines are different, and only one serial link will be active at any time, why does the quiescent link interfere with the active one? Will the scheme work if I just begin and end each link when it is needed?

Finally, do the SW serial links rely on timers 0, 1, or 2?

Thanks in advance for any insights.

2

How are you setting up your software serial (code)?

Weedpharma

3

SW serial is just set up with two instantiation statements, and two begin statements, as below.

  include <SoftwareSerial.h>


  SoftwareSerial netLink(6, 7);
  SoftwareSerial radioLink(8, 9);



 void setup()
 {
     netLink.begin(9600);
     radioLink.begin(9600);

     ...
     
}
4

Hi,

Not sure if this will help..

We will need to see your complete sketch.

Tom..... :slight_smile:

5

TomGeorge, you have probably solved my problem, but I'll wait 'til tomorrow to test it. I wasn't aware that only one port can be listening at a time. If that's the case, then I just need listen() statements before expecting data from either port. I have arranged the system so that each outlying Nano gets permission on a separate (third) line before it can transmit. Thanks. I expect that to work.

6

Perhaps set up the links between the nanos as an i2c bus?

7

SoftwareSerial is a bit of a kludge. Don't expect 2 instances of it to work.

You may be able to get my Yet Another Software Serial to work alongside SoftwareSerial - but I have not tested that.

...R

8

PaulMurrayCbr:
Perhaps set up the links between the nanos as an i2c bus?

+1