For some context, I want to create something like this. For now, until I change my chips (which I know I need to do as a plan to use a lower voltage Vcc2) I'm using the sn754410 h-bridge IC, 74HC595 Shift Register. I find that using two of these ICs (a total of 4 electromagnets) results in almost all of my digital I/O Arduino pins being in use. I'd like to use about 8+ of these h-bridge ICs (that would be 48+ I/O pins for the 8+ h-bridge ICs) but I don't know how I could do so while also maintaining a full duty cycle current (complete on 100%) at times needed.
My question would be what can I use to achieve this and still have the option to have a bunch of inputs on HIGH all at the same time (or really close to each other where they seem to have turned on all at the same time to humans)?
It seems like shift registers may have a PWM effect on the pins (clock?). Do shift registers have a PWM effect on the pins, therefore reducing the current going into the output of the h-bridge ICs?