so far ive hooked up a 74HC595 + 330ohms for each the columns of LEDs , and 74HC595 + ULN2803A for the LED rows.
That sounds wrong. The 2803 will only sink current and the 595 doesn't supply enough current to light more than one or two LEDs. Can you post a schematic?
I won't comment further in the matrix, have only worked with shift registers.
You can save some digital pins chaining the serial on the 595's together. You would unlatch them so there is no output, serial out the data to them then latch them. Using that you can daisy chain them to run more 8x8 displays and you'd not run out of digital pins on the Arduino. Once you've written a function the code is easy to read and maintain.
So far I've strung together 32 of 595 chips. I switched to HEF4794 due to it's higher current.
Not so far but it will depend on your software. When you write the multiplexing make sure that 2803 is the one that you put only one zero on at a time and put the data for that row on the top 595. This is the inverse of normal multiplexing. It is needed because the 2803 can sink enough current for 8 LEDs but the 595 can only source enough current for one LED.
Hello! I'm trying to do something with the same configuration of two 74HC595 integrated for a 8x8 matrix. Could you please pass me the software to guide me in performance. (Sorry I'm using an automatic translator, do not speak English)