Start to Finish Driving LCDs

Lumex Display with Microchip Driver for a TI MCU

- Stuart Ball

LCDs have displaced LEDs for many embedded systems and there are several reasons why OLEDs haven't completely taken over. Stuart uses a Lumex LCD with a Microchip driver for a TMC4 MCU to demonstrate the optimal setup. He then runs through some key criteria for selecting a display including customized options.

LCDs (liquid crystal displays) are used in a lot of modern electronics today. Most computer monitors and televisions are LCDs. Small embedded systems have LCDs. Although OLEDS have replaced LCDs in some applications, LCDs still find plenty of use.

LCDs have mostly displaced the older LED displays for alphanumeric information. LCDs are lighter, draw much less current, and can be read in conditions of high ambient light,such as sunlight. With a backlight, they can be read in low light or total darkness, although at the cost of increased power consumption.

We often use LCD modules with integrated controller ICs that provide a parallel, SPI, or I²C interface. An example would be the Lumex LCM-S01602DSF/C 2-line x 16-character alphanumeric display with a parallel interface.

High volume electronics often use LCDs without an embedded controller, the LCD module is soldered to the PCBA and controlled directly by the MCU, or by a controller that is in turn controlled by the MCU. An LCD without a driver is sometimes referred to as just the "glass".

OLED: What about OLEDS or Organic LightEmitting Diodes? An OLED uses more power than an LCD, but that's not really a fair comparison. A bare LCD is a reflective device, so it doesn't work well in low-light situations. An OLED is a lightemitting device, so it will work in low light. When you compare an LCD with an added backlight to an equivalent OLED display, the OLED may use less power. But this article is about LCDs.

LCD CONSTRUCTION