david,

thanks for pointing out my program code problems

as you said 8051's use active-low logic, most 8051's cannot source current only sink current

so is it possible that i can turn on a transistor with 8051?


i have 6 wires from the controller of a RF car

let's named them wire A B C D E F

wire A B C are for forward and reverse
wire D E F are for left and right

when wire A connected with C, the car move forward
when wire B connected with C, the car move reversed

so i planned to use a transitor to connect the wires,does it work?