Low-Cost LCD Controller (I)

Surplus stores often sell cheap matrix LCD modules, some brand new (NOS), others salvaged from broken or old equipment. Most of these displays have segment and common drivers on board but lack a controller and memory. This is different from the well-known LCD character modules with built-in HD44780 controllers and memory. Part 2 of this article will show the design and implementation of a low-cost 80C51-based controller for bare LCDs. First, however, this month’s instalment provides some background information on the operation of matrix LCDs.LCDs from surplus stores are cheap but problematic when it comes to actually connecting them. This is in sharp contrast (pun intended) with the displays usually applied in Elektor circuits because the latter are usually based on the industry standard HD44780 controller chip.