How do I reference x-axis or y-axis scale values to a worksheet ce

I would like to have a chart's x-axis or y-axis scale values (min, max, major
unit, minor unit, etc) reference a data cell. This way I could manually
change the scaling of the graph from the worksheet or have it scale
automatically depending on the input data.

OR if anyone knows how to simply have excel equate the x-axis and y-axis
scales, that would be awesome too. (ie. if a box (therefore equal sides) was
drawn in a xy scatter graph, it would look like a box in the chart, not a
rectangle)

Thanks in advance