I just got a batch of 20x4 HD44780 LCDs in and I noticed that this has very different circuitry compared to my older 20x4 LCDs. This one has a V1.3 marking on it, most of mine have V1.1. Most interestingly, it looks like the design might’ve considered integrating an I2C GPIO expander on the board …

Why not look at one of the most common I2C LCD backpacks, and see if it makes sense?

Hi, I would say it is the same old parallel model, but upgraded with I2C option. Try it, although I would think it has not got I2C components fitted for this model you have bought. You may have to run the I2C scanner first to see if it has an I2C address. Can you please post a link to where you…

Found it on aliexpress. The ad shows the old version in the pictures. YMMV. https://a.aliexpress.com/_mPAVHdK

Alright, so I got some time to hit it with the meter. Based off of the datasheet for the PCF8574, it seems like the IC would at least fit in the same spot, its GPIOs would go to the LCD's IO. PWR and GND are in the correct spots. Going off the schematic of the I2C backpack from Amazon seller "HiLe…

I don't see any ICS on the board that would hint that they've populated it yet. Wiring it up for I2C would probably just give the board power and thats it. I'll look into populating the board by getting an I2C backpack to donate its IC.

[image] emilad: getting an I2C backpack to donate its IC. Wouldn't it be easier to just buy the backpack and solder it to the 16 pin header instead of messing with the surface mount chip?

Just TRY it. What do you have to lose?

That Ali Express pages says: LCD2004 2004 20x4 2004A Blue/Yellow Green/White Screen SPLC780D Character LCD IIC I2C Serial Interface Adapter Module AIP31066 The SPLC780D and AIP31066 are hd44780 compatible chips that only support parallel mode. (controlling using DB0-DB7, RW, E, RS) i.e. no I2C The…

Funky 20x4 LCD with interesting circuitry

Other Hardware Displays

madmark2150 June 10, 2023, 2:37pm 3

I see SDA/SCL pins in th R edge, wire it up & see what happens.

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Funky 20x4 LCD with interesting circuitry

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