Hi dear friends
I want to drive 40x4 LCD by just one PCF8574 in my Arduino projects using I2C port.
Can anyone help me to wiring this project?
Explain it or any idea?
I had try 40x4 LCD I2C topic so many times, but there is nothing on my 40x4 lcd.
My Arduino version is 1.6.6.
Here is an plan in attachment.
Best regards & thanks a lot for any answer
Isn't that just a bog standard character LCD with the I2C backpack, just with more columns than usual?
I think you can just use the LiquidCrystalI2C library.
As for wiring - not sure what you're asking? It's the same as any other simple I2C device.
Ground to ground, 5v to 5v, scl to scl, sda to sda. May need pullups on the sda/scl lines (4.7k or 10k from each of those to 5v - these should be used, instead of just the internal pullups, but it looks like many people report no issue using those character LCDs with the I2C backpacks w/out external pullups).
Thank You DrAzzy
Please check attachment for wiring plan.
I mean if i use this THIS TOPIC lib for I2C LCD, which pin of PCF8574 gone to which pin of LCD?
There is 2 En pin on 40x4 LCD. One is E for first and second line, and the next is E1 for enable third and fourth line.
So, we must use 8 pin of PCF8574 for wire to LCD. How can you explain it.
Thanks again
In short,you are using generic two wire to 8 wires hardware interface device (PCF8574) and you want to use software library (I2C) which is designed to interface with dedicated / programmed device ( sometime referred to as "I2C controller" especially to interface with Hitachi (LCD) standards.
It is up to you to send appropriate data to the PCF8574 to emulate the functions of the I2C controller.
Datasheet for PCF8574 would help.
Not a trivial task, but I would guess someone already coded that. ( Not necessary for Arduino ).
As far as "wiring" PCF chip just follow standard Hitachi schema - control leads(RW etc) plus 4 bits data bus in addition to two enable signals.
Depending on specifics of your application / display, you may not need separate E1 and E2 signals , but you need to first build the software.
Personally , unless you REALLY want to build the conversion code, I would get "ready to run" I2C controller module and wire the E leads directly to enable them all the time or to Arduino I/O pins.
Good luck
Vaclav
PS here is a reference which could be also helpful. PLEASE note better / more correct explanation of enable leads on 40x 4 LCD .
http://www.microcontroller-project.com/character-lcd-pinout--working.html
