Hi!
I recently breadboarded an 8x8 RGB LED matrix display (see attached picture) using four 74HC595 shift registers (the second one from the Arduino Uno controls the anodes). I programmed it without PWM just to make LEDs light up in patterns and got it working ok. Using nested FOR loops I can make it cycle through the 7 individual and combined color combinations and have LEDs go horizontally/vertically around the display. But now I'd like to better understand how to get PWM working with shift registers. I noticed an online library that called shiftPWM but this will not work with LED matrices. I also would rather not buy a shield but would like to understand how to make this work via programming. There is a hint that this can be done with interrupts.
Second, I'd like to figure out how to turn on patterns of LEDs to make characters. So far, all I've been able to do is turn on individual LEDs or rows/columns. In fact, it doesn't seem possible with the way the matrix is wired to turn on patterns, such as the letter "A" in a 5x7 matrix.
Thanks!!!
Jerry
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