hi! may i enquire why did you use tpic6c595 in to drive the column and 74hc595 for rows and not the other way round?
My matrix is wired so the led current goes from the row to the column, and the tpic6c595 will only drain to ground, so i had to use it for the columns. You are on the right track to question my choice, it would be better to have the more powerful tpic6c595 to drive the common row and the less powerful 74hc595 for the individual columns. However, to do this, I would have to rotate my matrix (treating rows as columns and vice versa) -- not practical on my breadboard. 