Garbled letters with serial LCD (atlas ph stamp project)

You just aren't formatting the text properly. Numbers vary in lengtth and sign. The simplest solution is to add a couple of spaces after the output to ensure you are covering over what has been printed before.

If you trimmed down the pictures to show just what you need to show, you will get a lot more friends. Try Irfanview for free, and use the CTRL-Y trimmer