Let me describe my project: I'm bulding a count-up/count-down large format display timer with big 5x7 led dot matrices. I'm trying to use Keil uVision3 to program my microcontroller. I'm trying to use an at89s52 to control an TLC5920 LED driver chip. The LED driver chip needs Sin, SCK, LATCH(bar), BLANK, and CSEL0-2 from the microcontroller. I am a decent C programmer. But, I do not know how to use Keil to do things like send P2.0 serial data or P2.1 a high or low signal or monitor P2.7 for a pulse from a keypad. Could someone please direct me to a knowledge base that explains how to program such things in Keil evaluation? Also, I would greatly appreciate any project advice. Thanks, Lee Lerner