The max7219 is designed for common cathode LED displays and a single chip can handle up to 64 segments (8 displays having 8 segments each) or 64 individual LED's. But on the downside LED modules typically require more current than LCDs, have much lower resolution, and are more expensive for compared to a LCDs with similar resolution, and so on. LED modules are available ranging from small to very large (usually consisting of many smaller LED displays) and may be only able to display one of few colours for the segments or dots to the RGB type that can output thousands of colours. Generally, there are 2 main types of LED modules which are the 7-segment (or higher) types used to give numerical (and limited text) information and the dot matrix types which display numbers, characters, and symbols in a more easily readable format than the segment type. The LED display modules typically have a serial or parallel interface usually designed to be connected to some form of computer or microcontroller in order for the display module to receive instructions, such as the text or symbols to display, their position, colour, and so on.īecause LED displays have good contrast in most lighting conditions and do not require a backlight LED modules are ideal for equipment used both indoor and outdoor, as typically seen on home equipment as well as at train stations, to give a few examples.

For examples of LED displays please have a read of my overview of diodes and LEDs using this link:īy pairing LED displays with additional circuitry LED modules are able to accept commands and automatically refresh the display as well as be chainable (connected to one another in succession) to other LED modules, making the control of LED displays, especially large collection of displays, much easier. LED (Light Emitting Diode) displays can be found in many forms, capable of indicating letters, numbers, and other symbols.

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