In Excel, is there a set of events per cell. Can I trigger on data entry into a cell?

eg. As a user types chars, I want to help the user with unique expansion as in the following.

User types 3HN10
Expands to "3 Hearts by North Making 10"

I found the OnChange event to use after the event, but I cannot find anything to allow processing on entry of a cell.

Regards and thanks