POWERTIP PC1602F B Confusing Datasheet

Discussion in 'Embedded Systems and Microcontrollers' started by eb123, Jun 12, 2018.

  1. eb123

    Thread Starter Member

    Jul 3, 2017
    74
    2
    I've recently purchased the POWERTIP PC1602F B LCD Screen (http://www.farnell.com/datasheets/4...23.1140453447.1528831294-380640216.1528405894).

    Reading through, there are several things which aren't entirely clear:

    1) Pin Description - VO (Operating Voltage for LCD). What does this actually do? No description is provided. The diagram below the table shows an arrow pointing out from the pin, towards a resistor. What does this mean... Is the resistor actually required, or only if you want to change the screen contrast?

    2) What does the read pin do? Does it return the data you have sent to the screen?

    3) Display Command Table. This is where most of the confusion arises. What do any of the various symbols mean (I/D, S/C, DL, NN, AC, X, etc)?

    4) Assuming there are other LCD screen which work in a similar way, could somebody provide me with their datasheets, providing they make any more sense? Does any code exist for this particular screen? :)

    Cheers.
     
  2. AlbertHall

    AAC Fanatic!

    Jun 4, 2014
    6,671
    1,571
    1) The resistor with the arrow is a potentiometer (variable resistor). You will need to adjust this to get a good display. Before you start worrying about sending data to the display you adjust that pot and you should see some boxes where the characters will be displayed. Adjust so the boxes are just barely visible.
    2) It allows you to read the busy flag so you know when you can send more data. Without this you have to put in large delays to ensure the display has finished the last thing you sent it. From the datasheet:

    "Be sure the ST7066U is not in the busy state (BF=0) before sending an instruction from the MPU to the
    ST7066.
    If an instruction is sent without checking the busy flag , the time between the first instruction and next
    instruction will take much longer than the instruction time itself.
    Refer to Instruction Table for the list of each instruction execution time .

    There is lots of code ready written and descriptions on www.
    Also note that there is a specific setup sequence you must follow, especially if using the four bit data access method. It is much easier to at least start with ready to run code.
     
  3. danadak

    Well-Known Member

    Mar 10, 2018
    1,908
    395
    1) Pin Description - VO (Operating Voltage for LCD). What does this actually do? No description is provided. The diagram below the table shows an arrow pointing out from the pin, towards a resistor. What does this mean... Is the resistor actually required, or only if you want to change the screen contrast?

    The Vo pin sure looks like a contrast adjust, The arrow is a symbol, part of the variable pot symbol. Adjustable Resistor acting as an adjustable V for contrast adjustment.

    2) What does the read pin do? Does it return the data you have sent to the screen?

    Look at the onboard controller datasheet on the module, for read operations.
    https://www.newhavendisplay.com/app_notes/ST7066U.pdf


    3) Display Command Table. This is where most of the confusion arises. What do any of the various symbols mean (I/D, S/C, DL, NN, AC, X, etc)?

    Again look at controller datasheet -

    Ø I/D : Increment / decrement of DDRAM address (cursor or blink)When I/D = "High", cursor/blink moves to right and DDRAM address is increased b
    When I/D = "Low", cursor/blink moves to left and DDRAM address is decreased by
    * CGRAM operates the same as DDRAM, when read from or write to CGRAM




    4) Assuming there are other LCD screen which work in a similar way, could somebody provide me with their datasheets, providing they make any more sense? Does any code exist for this particular screen? :)

    Regards, Dana.
     
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