Looking at building a 4 digit 7 segment LED multiplexed display. Some of the **examples of the hardware indicate segment control as being supplied by transistors for each of the 7 segments. I have common cathode available.
I am thinking that if I use resistors for each of the segments to supply 20mA or even a little less, then I don’t really need to drive the segments with a transistor for each segment. I think the Mega32 pins could handle this with no problem.
Of course, the common cathodes (digit select) will be transistors to sink the current to ground and enable a particular 7 segment display.
I don’t want to use one of the maxim chips as I have done that in the past. This is an effort to experiment using the timing required to multiplex and other task on the ATMega32. I am only looking for comments on the hardware setup in particular driving the individual segments from the AVR pins without using transistors with the exception of using transistors for digit select.
** various sites on the Internet
Thanks in advance