I'm getting frustrated because I keep buying parts that I don't need. I want to cheaply control a common annode/common cathode LED matrix.
At first I thought I needed a mutliplexer to do this. So I bought a bunch of SN74150N "multiplexers". After spending 4 hours trying to simply understand what this chip does I gave up on. I thought a mutliplexer simply bridged or closed the switch between the output pin and whatever input pin you are selecting. This thing rather, reads the input pin I've selected and gives me the inverse reading on the output. That doesn't sound like a multiplexer to me.... I don't know what this chip would really be. Why does the manufacturer think they're making a multiplexer? What don't I understand about multiplexing?
Second I bought a multiplexer that actually does just what I think a multiplexer should do; bridge or close the switch between the input pin I've selected and the output pin. The multiplexer I bought was the cheap $0.50 CD4067BE. This would work brilliantly if not all my cathodes were common ground. I want to actually control 2 pins on the LED matrix at a time, a annode pin and cathode pin. The CD4067BE only gives me one output at a time. I may be able to use 2, 8 input multiplexers to control one 64 LED matrix though. The CD4067BE has 16 inputs though so I don't think this chip will work for my task.
Maybe what I need is a shift register? I don't know what that does but the word pops up a lot when dealing with an LED matrix...
Maybe what I need is a latch? I don't even know what a latch is either...
I've heard the MAX7219 "LED driver" too. However those chips cost $8.00 each and that simply seems very expensive for an IC. Isn't there a cheaper "LED Driver" that is just as good (16 pin output)? Why do people refer to this chip as a multiplexer when it isn't one? It uses clock signaling to turn the outputs on/off which is not the way a multiplexer works from what I understand.
I recognize that I'm very confused at this point. Thanks to anyone who can help me get straightened out!