My questions are:
a. Can VS1000/VS1000 Audio Module perform (1) and (2) while playing music (4). Does VS1000/VS1000 Audio Module have enough processing power for this? There must be no gap / jitter when playing the background music / reading aloud the name.
b. Does VS1000/VS1000 Audio Module have any API to product a continuous square wave (1)? If not, should I use a for-loop?
c. Should I use an interrupt for (2)? If not, should I use a for-loop?
d. Do I need to be concern about the program/memory size, especially when the employee list becomes very long? I will probably not able to put the whole employee list in the memory of VS1000/VS1000 Audio Module. But I hope I can scan the uSD card directory to find the corresponding file quick enough to play (3).