Apologies… Posted in possible wrong forum
First time posting, so please give me a bit of patience if I stray, but I’ll try and be on point.
I have been working with a project(s) that use a 20x4 Line LCD display with the Serial I2C interface.
All of the displays I have used to date have had the default address of 0x27 Hex.
Last week I received some additional modules, lo and behold “no Display data”. Tried a second LCD and same scenario. I2C Scanner to the rescue, it revealed an address of 0x3F Hex. And no way to change the address to 0x27, you can get it to 0x38 by shorting All address lines.
The Problem is the older I2C interfaces have had the PCF 8574T Chips and the New I2C interfaces have the PCF8574AT Chip. Difference is one has a default value of 0x27 the other has a default of 0x3F.
Here is my request for help: (Finally)
There is a way to interrogate the I2C bus and find one (0x27) or the other (0x3F) address.
But how can I insert that discovered address (byte addr) into the
[ (LiquidCrystal_I2C lcd(addr,2,1,0,4,5,6,7,3,POSITIVE); ] object?
I have tried a couple of simplistic approaches but unsuccessful.
I hope someone has seen this problem before and solved it. !