MAX7219 is an integrated serial inputoutput common cathode display driver that connects a microprocessor with an 8bit 7segment digital LED display as well as a bar chart display or 64 independent LEDs It includes an onchip Btype BCD encoder multichannel scanning circuit segment word driver and an 8 8 static RAM for storing each data There is only one external register used to set the segment current of each LED A convenient four wire serial interface can connect all generalpurpose microprocessors Each data can be addressed without rewriting all displays during updates MAX7219 also allows users to choose whether to encode or not to encode each data The entire device includes a lowpower shutdown mode of 150 A analog and digital brightness control a scan limit register that allows users to display 18 bit data and a detection mode that causes all LEDs to light up
