GLCD

Types of graphical display

Monochrome

These displays are typically arrays of pixels that can be either switched on or off.

They tend to be fast to refresh and low cost but are limited in terms of what they can display.

Colour

These displays are typically arrays of pixels that have associated red, green and blue colour channels. Each colour channel will have a bit depth that dictates what resolution is available for that colour. A common colour bit depth is 565 where the red and blue colour channels have 5 bits (0-31) and the green colour channel has 6 bits (0-63), making a total of 16-bits that are easily transferred using two standard 8-bit byte transfers.

The GLCD component is aware of the colour depth of the display and will automatically convert and scale the assigned RGB colour byte (0-255) to the correct bit depth.

They tend to be slower to refresh due to the increased data per pixel and slightly higher cost but can display full colour images.

Serial

Serial displays have a pin for clock and a pin for data in. The data is transferred a single bit at a time by placing the data onto the data pin and then strobing the clock pin.

These types of display consume less pins of the host microcontroller but tend to be slower as you have to individually clock in each bit.

Often these types of display can be used with an SPI peripheral to help speed up the data flow into the display. This is because the SPI peripheral can often output data much faster then simple pin toggling.

Parallel

Parallel displays often have a number of data pins up to 8 or 16 and a single clock pin. This allows you to clock in a number of binary values at once significantly increasing the speed of sending data to the display.

The downside to this is you require a lot more connections to the host microcontroller.

Examples

Changing the display

If you want to replace the display in one of the examples with a different display type then information on how to do this can be found on the Replacing a Component page.