Skylar
Well-known member
Bluzzi said:
Modern low-end microcontrollers (8-bit PICs / AVRs) operate at 12–16MHz, which is very fast.
If you used discreet digital outputs built into the chip (not likely if you've got more than 20 or so channels to mute), the time it would take to switch these outputs from LOW to HIGH (or vice versa) for signaling a mute might take 1 to 2 clock cycles + the rise/fall time of the outputs.
We're talking about nano-seconds here.
So, switching 48 mutes at once would sound like it was done in unison, as there would be only nano-seconds between each successive mute.
The total time for muting all channels might be something like 8.6 micro-seconds (that's with a 12MHz microcontroller taking 2 clock cycles to change the state of an output pin with the rise/fall time of each pin being 13ns).
Realistically, you could not do that with 48-channels of muting because the microcontroller will likely not have enough GPIO pins for all 48 channels.
So, you'd use three 1:16 multiplexers instead (some multiplexer switch times are <= ~20 nano-seconds and can be considered negligible).
In this scenario I can see the total muting time being more like 45–50 micro-seconds (5 more pins to set per channel to be muted).
That's 1/20th of a millisecond.
You still wouldn't notice it.
