i've been attaching the i2c LCD to raspberry, i can only turn off the lcd on and off using msg.action, but while integrating a function , the LCD remains blank....
You haven’t given much information. You haven’t said what the function does, you haven’t told us where it is in your flow we don’t know the version of node-red or node-js, what pi you are using, what os?
When you want help, it’s best to provide enough information so the person - who is volunteering their time to help you - has enough information to help you.
here you can see the raspberry couldnt read the i2c....i tried several functions from other people's flows...i'm using a rasp os + node v 2.1.6+ pi 4
As you say, the pi doesn't see any i2c devices, so it's not a node-red issue.
Probably the raspberry pi forum is the best place to ask for help, but have you enabled i2c in raspi-config?
Please start up node-red and copy and paste the startup log in a reply.