Pin Numbering and Orientation
The top side drawing contains a mark that indicates part orientation. The orientation is used to define how the pins are labeled. Dual in line packages are numbered from lowest to highest in a circular method from the mark. Ball Grid Arrays are labeled as a matrix with numbering along the top and bottom edge, and lettering along the left and right edge. All pins are derived from the combination of a number and letter.
These labels can be identified in the Signal section of the Data Sheet.