Can't I control more than 2 lcds respectively?

[eungae04]

I want control those 2 lcd screens respectively.
Can't I allocate more SCL/SDA port?

[jim-p]

On most LCDs you can change the I2C address with solder jumpers on the back of the LCD.

[xfpd]

@jim-p

change the I2C address

I2C/SPI LCD Backpack

[jim-p]

Yes, you can change the address

[oldcurmudgeon]

And some backpacks have a different (A version) of the interface chip which has a different base address. This gives you 8 additional address possibilities.

[gilshultz]

With the backpacks I use they have a PCF8574 or a PCF8574A, they have different base addresses (0x20 an d 0x38) so that allows me up to 16 LCD displays without any work. There may also be others at a different address, but I do not know for sure. xfpd gave you a nice chart, giving you the jumper patterns. Pages 5 and 6 of the data sheet give a better explanation of how the address work. https://www.nxp.com/docs/en/data-sheet/PCF8574_PCF8574A.pdf

[eungae04]

Thanks!

[eungae04]

Thank you

[eungae04]

Thank you!

[eungae04]

Thanks you too!

[JohnRob]

After you get your I2C addesses' sorted out, before you run your program you should run this scanner program. It looks for every possible I2C address and reports what it finds. It should show the two I2c address's, one for each display.