Sorry if the title is wordy. Basically what I am asking would probably be easier if I just use an example.
Say I wanted to plot f(x) = Asin(x) and have the graph come up with the sine function, and then the tics on the y axis be like half integer multiples of A. What I have been doing for my homework assignments is just plotting f(x)=sin(x) and then turning off the ticks and manually adding my ticks. It would be really cool if mathematica could do this for me.