Due to a bug in Quartus® II software versions 11.1sp2 and later you might see the following error message when trying to generate a reduced MIF file with altgx_diffmifgen.exe for an Arria® II GX TX only instance.
Traceback (most recent call last):
File "<string>", line 499, in <module>
File "<string>", line 489, in altera_main
File "<string>", line 348, in read
File "<string>", line 255, in calc_word_line_number
AttributeError: diff_mif_gen instance has no attribute 'has_rxpll'