Leaderboard

For time-multiplexed LEDs you can exceed the 20mA current rating or whatever the datasheet says. Some even give a peak current rating that is valid for a given duty cycle (normally 10% rather than our 12.5 or so) and pulse time. Totally depends on your LEDs. A tip is to use super bright ones, but probably you already have something installed. In the SEQ v4+ we use 47R but these are superflux RGB LEDs designed for more forward current. Generally the higher the pulse energy, the lower the lifetime of the LED. Keep in mind that the 74HC595 outputs are overdriven in this configuration. Your +5V rail will sag and in the worse case it won't be enough to power the PIC properly. But many MIDIboxes work fine like this :).