> I'll have 5 times as many resistors if I put them on the cathodes, > reason being that I'll need to put them on the cathode for every > column Oh, yes, I see that now. Teach me to look to the right more often But you could instead put 7 on the low side ? Each resistor is then effective for a column, not a row. Compare yours with http://www.mikroe.com/en/books/8051book/ch7/images/21.gif Instead of R20 - 27, resistors could be on the collectors of Q1 - Q4 (You should adjust my column count in other posts from 6 to 7 BTW) -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist