// PWM 
#include <REG1210.H>
#define OneUsConst	(2-1)
sbit p33=P3^3;

void main(void)
{	
	PDCON &= 0x0ed;	//turn on tone gen & sys timer
	USEC = OneUsConst;
	p33=1;			// turn on P3.3 
	PWMCON=0;		// select PWMPeriod
	PWM=5;			// Set PWMPeriod
	PWMCON=0x10;	// select PWMDuty	
	PWM=4;
	PWMCON=0x09;		// Enable PWM
	while(1) {} 
}