servo control using port

[daisordan]

Hi, i connected a servo signal to RD7 in PIC18F4455. I have done the experiment for the servo movement left = 500us, right = 2ms. I use the delay to work out the pulse but it doesnt work. The servo was just stop here. Is there any problem with my code? how can i fix it?

void main (void){
TRISD=0b00000000;
PORTD=0b00000000;

PORTDbits.RD7=0;
Delay1KTCYx(5); //delay for 20ms
PORTDbits.RD7=1;
Delay100TCYx(5); //delay for 2ms
while(1)
}

PS:using Fosc=1MHz

 

[Triode]

while is at the beginning of a loop, not the end. You should encapsulate the stuff that loops like this

while(1)
{
//code that loops goes here
}

as is, your program sets the ports, then turns RD7 off and on once, then loops at that while(1) at the end forever.

 

[daisordan]

thx for ur reply
i have changed it but still doesnt work

 

[Triode]

Try connecting it an LED in series with 220 ohm resistor instead of the servo pin. Set the delays to what you think will make it blink at 1 Hz. This will tell you if the chip is running, if the port is working as an output, and if the timing is what you think it is.