I need some help with this. Not sure if I can do this, but I want to try. I have saved from the recycle bin an old IEE Flip 40x2 VFD. It works, I've gone through the EEVBlog video that uses an Arduino to send simple characters to display and that seems fine. However, I would like to try and get one of my PCF8574 LCD adapters to work with it so I can use I2C to control it.
I have the original datasheet for the display so all of the pin outs, commands and everything are known. The supply and logic voltage are both 5VDC so there shouldn't be any issues with that. Where I get lost is when I try to match the connections between the adapter and the display. Different terminology, board markings, is not matching up to what I see, what I think I need to do and what makes sense to me so I'm hesitant to test this.
Can this adapter be used to control this display or am I just wasting my time? I'd really like to use this display in a project and using the adapter will greatly simplify the logic.
Yes it is easy, just connect the wires to the correct pins. Sorry I cannot determine which pins do what as there is no technical information or an annotated schematic of your proposed solution.
First you need to determine whether the display connectors have exactly the same function as the adapter connectors. If not, then you can't match them without additional circuitry.
Can the display work with 4 data bits. If it needs 8 data bits, there will be no room for control signals on the PCF8574. The PCF8575 PCF8574 is an 8 bit device.
Please post a schematic from the video, I am not going to sit through a video to get information needed to help.
Looking at the schematics that I can find for the adapter, D0 through D3 are not connected to the 16x2 LCD's that these are normally used for. That must mean these adapter's are 4-bit when they are intended to control a 16x2 LCD.
The datasheet for the display states that all control codes are in 8-bit ASCII, page 3 and 4, so 4-bit isn't going to work.
The PCF8574 datasheet says the chip is an 8-bit and there are a couple versions of these adapters that say they are 8-bit I/O expansions. Those adapters only have the 8 data pins and one INT pin. Might these adapters work with some additional components to drive the CS, A0 and Read pins on the display?