LED driver data sheet

Discussion in 'General Electronics Chat' started by Turtlexya, Feb 4, 2014.

  1. Turtlexya

    Thread Starter New Member

    Feb 4, 2014
    Hello everyone

    I've been looking at an led driver that would allow me to interface many LEDs with few uC lines and came across the MAX7219CNG on Jameco. I was trying to follow the data sheet but got lost really fast. I am having issues understanding how it is controlled and how i would be able to manually connect 64 individual LEDs to it. I understand i can write a 8 bit command that would toggle pins D0-D7 on/off, but can't find how to toggle pins SEG A - SEG DP and have an 8x8 matrix of LEDs. I think this would be done by having 8 lines for high and then 8 lines for low, but that doesn't seem very intuitive. It seems to me that for a matrix like that to be built then some LEDs would come out to be in series with each other.

    Here is the data sheet of the driver


    Thank you in advance
  2. shteii01

    AAC Fanatic!

    Feb 19, 2010
    It seems to me that each SEGx provides current for each digit (each digit is made of 8 led) The DIGx pins are the "grounds".

    Notice the first paragraph in the very begining: "General Description
    The MAX7219/MAX7221 are compact, serial input/out-
    put common-cathode display drivers that interface
    microprocessors (μPs) to 7-segment numeric LED dis-
    plays of up to 8 digits, bar-graph displays, or 64 indi-
    vidual LEDs

    You got 8 SEGx, each of them controls 8 led, total of 64 led.
    Turtlexya likes this.