As Jesús Ángel Martínez Mendoza notes in his μMUX Mind writeup, “Each tutorial on LCDs begins with an Arduino.” So it appears. His challenge, nevertheless, does away with the Arduino, or any microcontroller in anyway, as a substitute driving a 16×2 LCD with multiplexers and logic gates.
It’s an bold objective, however with some tidy breadboarding, he’s made it appear like a moderately achievable challenge. The system is split into six purposeful blocks, with the management unit, knowledge reminiscence, instruction guide (person enter), and twin enter (LCD) sections on the primary multi-breadboard setup. A distinction/brightness adjustment unit sits on an outer breadboard, whereas the facility provide seems to be like a typical backup battery on the skin, however has its personal customized electronics inside.
The system implements an NE555 clock generator for synchronization, whereas a sequence of multiplexers act as ROM to retailer 4 preprogrammed – i.e. prewired – directions which might be despatched to the LCD in sequence by a four-bit binary counter. As soon as the sequence is completed, the person can enter eight-bit ASCII codes through the onboard buttons for show.
The system is a formidable demonstration of simply what could be achieved with out a microcontroller or software-programmable logic, and can be massively academic for anybody trying to duplicate the setup. Whereas Mendoza discovered so much constructing it, he notes numerous potential future enhancements that may very well be utilized, together with an enlargement of the reminiscence to 8×8 phrases for full-screen ASCII show. He might have a number of extra breadboards!
