Fast serial LCD interface

serial lcd

This is a serial interface for any LCD using the incredibly common 44780 controller. There are a couple different serial interfaces like this on the market, but this project aims to be a superior version. It can use 5 – 30V with an included regulator. It has ESD protection. True RS232 levels mean you can use really long cables. Up to 8 buttons are also supported. This would work great with a car computer. All of the software and schematics are provided. Have a look around the madhacker site for a lot of other cool projects.

[thanks Stuart]


  1. kURTROEDEGER says:

    I just love LCD hacks.

    –Kurt Roedeger

  2. jaguarrrr says:

    why would you bother to build a serial interface for the 44780 ? (I really want to know…)

  3. hex4def6 says:

    #2: Because using a parallel port to drive the thing sucks?

  4. jason spence says:

    i’d like to point out that many of maxim’s 232 interface ICs include 15k esd protection.

    the rest of the circuit doesn’t seem to include esd protection. there should probably be a metal-oxide varistor and transil somewhere north of the 7805, to deal with spikes in automotive environments.

  5. Jason spence says:

    Oh, and the 74174 is a Hex D Flip-Flop with Common Clear. It seems to be used as a 6 bit serial->parallel converter for the data line coming out of the pic.

  6. xSmurf says:

    I’m currently working on a serial/parallel VFD (Vacuum Fluorescent Display) project. I picked up a few of these on eBay they are 40×2 VFDs have parallel and serial. VFDs are nice as they generate their own light, unlike LCDs and thus are much brighter. I use serial to drive the vfd… keeping things simple. As for input I use a 16×16 keyboard from Parallax (, costy), a 74C922 16 key to binary encoder (plans on, grabbed at and a 6402 based UART (plans:, hard to find, but I picked up a few free samples on the net). I’m considering replacing the UART with one of these nice little FTDI USB => Serial/|| chips. The electronics works good for the most part. Software wise it’s another story. I haven’t seen a single LCD app for the mac (osx, so posix interface). I decided to write my own, learning C at the same time. But I don’t think I have the agily with C to create such a project. Anyone knows of a simple open source project that could help me start out?

  7. KyleYankan says:

    Does anyone know of a stand-alone in-case LCD? I’d really like to make/buy one for my computer, so I didn’t have to leave the monitor on 24/7. Plus, the coolness factor

  8. hex4def6 says:

    matrix orbital make faceplates for these lcds that fit in a standard drive bay. They also sell serial LCD displays, but they’re pricy if I remember.

  9. Brandon says:

    you can dremel out a blank drive bezel and poke the LCD screen through. a 16×2 LCD screen is about $6, and if you’ve got an old parallel cable lying around… Coolness on the cheap.

  10. epooch says:

    quote:”I haven’t seen a single LCD app for the mac ”

    you can check out my project here:

    It uses a cheap USB -> parallel printer converter rather than
    USB->serial -> parallel

    I also have a small command line program to write data to the LCD

  11. Per says:

    I’ve been looking like mad for this exact thing but based on an AVR instead of PIC. Does anyone konow of such a project?

  12. tony says:

    Just wondering is there any good suggestions for a really cheap 4 line LCD with serial interface??? or even a cheap LCD serial interface controller is fine too (as long it can support up to around 4×20 characters) I actually found a few but they r all kind expensive I hope i can keep it under 40 dollars with LCD and controller or the LCD with serial interface

  13. vihar says:

    sir i am a hardwer &networkenng…. & can you give trick of how can change bios (post)screen
    like you see on post screen
    intel pentium 3 1 Ghz
    how can change this sentece
    Intel Pentium 4 3.2 Ghz
    please reply me at

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