Reverse Engineering an LCD Display

These were probably a custom order for some product (anyone wanting to dig further into the mystery can try to find what that could be) as there are clearly enough pins on the connector for an 8-bit interface, but they omitted connecting the 4 lower data bus bits.<p>On the other hand, all alphanumeric LCDs are almost certainly going to have a controller with the same or nearly the same instruction set as the infamous HD44780.<p>Nonetheless, longer single-line sizes than 16x1 are not entirely nonexistent; here&#x27;s someone who has a 24x1:<p><a href="https:&#x2F;&#x2F;forum.arduino.cc&#x2F;t&#x2F;liquidcrystal-begin-documentation-update&#x2F;416746" rel="nofollow noreferrer">https:&#x2F;&#x2F;forum.arduino.cc&#x2F;t&#x2F;liquidcrystal-begin-documentation...</a><p>Here&#x27;s a few other 32x1 I found:<p><a href="https:&#x2F;&#x2F;orioleindia.tradeindia.com&#x2F;alphanumeric-lcd-modules-244215.html" rel="nofollow noreferrer">https:&#x2F;&#x2F;orioleindia.tradeindia.com&#x2F;alphanumeric-lcd-modules-...</a><p><a href="https:&#x2F;&#x2F;www.cselettronica.net&#x2F;elettronica&#x2F;optoelettronica&#x2F;moduli-lcd&#x2F;lcd-32x1-hdm32111h-1-000.1.1.91.gp.5118.uw" rel="nofollow noreferrer">https:&#x2F;&#x2F;www.cselettronica.net&#x2F;elettronica&#x2F;optoelettronica&#x2F;mo...</a><p>(One of Google&#x27;s most noticeable degradation in search results is when searching for parts like this. I&#x27;m sure there are plenty more sites where a 32x1 character LCD can be found, but it&#x27;s just not returning them.)

<i>...while sanding I quickly realized that the chip under the epoxy couldn&#x27;t be a ST7066 after all. The ST7066 can only drive 16 characters.&quot;</i><p>It&#x27;s amazing how doing something repetitive and &quot;zoned out&quot; like this can clear your head and make room for fresh breakthroughs. I spend a couple days plugging gaps in my work schedule by sanding custom furniture I made, and felt slightly more productive each time I went back to my desk afterward.

Of note, the ST7070 was made for the European market for extra chãrǎctér süppørt. A custom library already exists for interfacing with it and the page has some interesting additional details about the chip: <a href="https:&#x2F;&#x2F;werner.rothschopf.net&#x2F;202003_arduino_liquid_crystal_st7070_en.htm" rel="nofollow noreferrer">https:&#x2F;&#x2F;werner.rothschopf.net&#x2F;202003_arduino_liquid_crystal_...</a><p>As a side note, the text on the chip when photographed at 200x appears to say “VIA-AEPT-A CHP-A” when you turn the image upside down :). <a href="https:&#x2F;&#x2F;imgur.com&#x2F;a&#x2F;4BpivfH" rel="nofollow noreferrer">https:&#x2F;&#x2F;imgur.com&#x2F;a&#x2F;4BpivfH</a>

On a similar subject: Reverse engineering of a Kindle e-Ink display. <a href="https:&#x2F;&#x2F;arxiv.org&#x2F;ftp&#x2F;arxiv&#x2F;papers&#x2F;1605&#x2F;1605.05174.pdf" rel="nofollow noreferrer">https:&#x2F;&#x2F;arxiv.org&#x2F;ftp&#x2F;arxiv&#x2F;papers&#x2F;1605&#x2F;1605.05174.pdf</a>

I have an LCD display salvaged from a knockoff calculator that I had been keeping for one day I might try to reverse engineer it. This stuff is both informative and fun. Good work thanks for sharing!

Working datasheet link @ <a href="https:&#x2F;&#x2F;crystage.com&#x2F;pdf2&#x2F;Sitronix&#x2F;ST7070.pdf" rel="nofollow noreferrer">https:&#x2F;&#x2F;crystage.com&#x2F;pdf2&#x2F;Sitronix&#x2F;ST7070.pdf</a>

I was hoping to do a similar thing recently, hoping to be able to reverse engineer an LCD screen from a digital picture frame I got at a thrift store for a couple of dollars. I thought I might be able to use it as a screen for my 6502 homebrew computer. I very quickly gave up though when I saw how many pins it had. I did find a datasheet for the screen, but going through the pin descriptions of each of the 60 pins, I realized there&#x27;s just no way this is a good fit for my project.

I&#x27;ve been doing something very similar with some VFD displays. I&#x27;ve had the Oscope and the LA out, but mercifully haven&#x27;t had to decap anything to figure them out (yet). Pretty much figure out the voltages (important!) and get an idea of the pinout and start by assuming an HD44780 or derivative and see how far you get.

I have a bunch of large 10&quot; LCD &quot;atomic&quot; wall clocks that use WWVB for time information. I want to retrofit something like an ESP32 running NTP. I can never find any specs on how to drive the (non-standard) LCD segments with numbers and icons. Has anyone reverse engineered one of those?

A little off topic, but what possibilities are there to rip out the guts of a &quot;smart tv&quot; and just use the display as a dump monitor? I love my Samsung display for its visuals, but the OS is terrible.