The HDSP2111 is a very nice LED display, the can show 8 alphanumeric characters in a 5 x 7 dot matrix, and are all packaged in a standard 15.24 mm (0.6 inch) 28 pin DIP. The onboard CMOS IC has 128 ASCII characters which are permanently stored in ROM.

 The HDSP2111 devices are 8-digit, 5 x 7 dot matrix, alphanumeric displays and are all packaged in a standard 15.24 mm (0.6 inch) 28 pin DIP.The onboard CMOS IC has the ability to decode 128 ASCII characters which are permanently stored in ROM.

In addition, 16 programmable symbols may be stored in on-board ROM, allowing displaying user made symbols and icons. Seven brightness levels can adjust the display intensity and power consumption.The HDSP2111 is designed for standard microcontroller interface techniques, we use the ATMEGA328. The display and special features are accessed through a bidirectional 8-bit data bus. The display has a data bus of 8 bits and a address bus of 5 bits.The address inputs A0 - A2 select a specific location in the character RAM, the flash RAM or the UDC RAM. A3 and Aare used to select which section of the memory is accessed.