LED display replacement for HD44780?

I'm designing an interesting piece of hardware: a 4-digit 7-segment LED display with shift registers and exact foot print as a 16X2 HD44780 display, even the 5V and GND pins will match, besides the shift register pins are on the HD44780 D5-D7 since most people use 4 bit mode. This will a drop in replacement of a 16X2 HD44780 display. You just have to use the right program to work the shift registers but all pins fit and so on. I ordered some LEDs already. Will start design once the semester is over. This will be great for clock projects.

Any interest, suggestion?

it would be great if you could make it a 1x4 display that is HD44780 "compatible", so it can be used with the standard lcd lib ...

Yes, a small processor could replace your shift registers and expose a hd44780 interface. It would likely be as cheap if not cheaper, and easier to use fir he masses :wink:


I did this some time ago

I desolded the chip off a broken 16x2 lcd and transplanted it onto my own led matrix board and communicated useing the original lcd interface useing 4bit to make a 8x2 or 1x16 display depending how it was wired.
The HD447800 chip can't drive the leds directly without row driving transistors but the concept is proven