• Verilog Code for HPDL1414 Display Interface

    Andrew Tudoroi • 10 hours ago • 0 comments

    Data for the display is stored in a small memory block 16 bytes deep and continuously refreshed.
    To print data on the display we need to put the char in the memory that is done by   verilog UART module.

    Demo: Running on the icebreaker board.

    IMG_6135.jpeg

    Tx and Rx line are physically connected to the FPGA pins:

    set_io -nowarn RX          6
set_io -nowarn TX          9
    Data path:


    Timing diagram:

    Capture.PNG

    For the complete Verilog code, refer to the project repository: https://github.com/ADDTDR/HPDL-1414-Pmod-Module/tree/main/Software

  • Prototyping

    Andrew Tudoroi • 12/19/2024 at 01:03 • 0 comments

    I was drawn to LEDs and old-school displays early on. One day, while browsing online, I came across bubble displays—particularly the beautiful HPDL-1414 alphanumeric displays. The aesthetics of these retro LEDs immediately caught my attention, and I knew I wanted to build something with them.


    This is how my simple and fun project started. It’s a small, solder-friendly design that combines my passion for retro tech with modern usability.

    The HPDL-1414 displays are both visually appealing and surprisingly easy to use. They’re smart displays, featuring an embedded character ROM that allows you to send simple 7-bit ASCII codes to display text.

    source : https://www.farnell.com/datasheets/76528.pdf


    By manually sending the data to data bus D0-D7 pins, and Digit position on A0-A1, charts can be already put on display.


    source : https://www.farnell.com/datasheets/76528.pdf
    This simplicity makes the HPDL-1414 perfect for debugging, displaying outputs for FPGAs, or building devices using those retro led displays.

    Prototype 0 conected to 595 shift registers and Arduino board.

    The PMOD Board Design

    To combine functionality with ease of use, I designed a small PMOD-compatible board that houses the HPDL-1414 displays.
    The board connects using two 12-pin PMOD connectors, making it ideal for use with FPGAs or microcontrollers. It’s simple, compact, and efficient—exactly what I wanted for a retro display module.




    Pcbs arrived,  and after very delightful and sort soldering process its ready to be tested