| ??? 01/21/12 12:17 Read: times |
#185597 - (Back to) Basics Responding to: ???'s previous message |
David Prentice said:
Your 7-segment displays need current limiting resistors. Basic electronics: http://www.kpsec.freeuk.com/components/led.htm Another way is to multiplex all the segments, 8 segment resistors, one 'column driver' chip Animated illustration: http://www.8052.com/forum/read/142043 an AT89S52 cannot sink very much current per pin. So you would need segment driver chip too Not necessarily. You could use a common-anode display - so each port pin would only have to sink the current of 1 segment. For a digit driver, just a simple transistor would suffice... Or you could multiplex just one segment at a time: http://old.8052.com/forum/read.phtml?id=117410 (thanks, Richard). |
