Two Servos with ST10 microcontroller

[w_bwr]

Controller : ST10F276
Compiler : Tasking

I have written a program to drive two servos simultaneously. Both Motors are programmed to have identical movement.
Motor 1 is connected to P7.0 & Motor 2 is connected to P7.2. The program works fine with only one motor regardless of which pin it is connected to.
When i connect the 2nd Motor, both motors gets stuck at one position. If i remove one of the motor, program works fine again.

This program controls the servo by serially communicating with a computer _ 'c' for center, 'r' for right and 'l' for left.

#include <regf276e.h>

_sfrbit LED4 _atbit (P3,9);
_sfrbit LED5 _atbit (P3,15);

int mspulse,pulse_value;


void Setup(void)
{
	T78CON = 0x4042;
	
	_putbit(1,DP3,9);
	_putbit(1,DP3,15); 
	_putbit(1,DP7,0);
	_putbit(1,DP7,2);
	
	T7IC = 0xc4;

	_bfld( DP3, 0x0c00, 0x0400 );
	_putbit( 1, P3, 10 );
	S0CON = 0x8011;
	S0BG = 0x0067;
	
	S0RIE = 1;
	S0REN = 1;
	IEN = 1;
}

_interrupt (0x3d) void Timer7_int (void)
{
	LED5 =!LED5;
	mspulse = pulse_value*2;	
	if (_getbit(P7,0) == 0)
	{
		_putbit(1,P7,0);
	 	_putbit(1,P7,2);
		T7=65536-mspulse;		// 1 ms delay
	}
	else
	{
		_putbit(0,P7,0);
	   	_putbit(0,P7,2);
		T7= 65536 - (20000-mspulse);		// 19 ms delay
	}
}

void delay_us(unsigned int us)
{
	unsigned int i;
	if (us<1) return;

	i = us*8;
	T8 = 0;
	while (T8<i)
	{
		_nop;
	}
}

void delay_ms(unsigned int ms)
{
	unsigned int i;
	for (i=0;i<ms;i++)
		delay_us(1000);
}

void Move_Left(void)
{
	if (pulse_value <= 500) return;
	
	pulse_value = pulse_value - 100;
}

void Move_Right(void)
{
	if (pulse_value >= 2300) return;

	pulse_value = pulse_value + 100;
}

void Serial_Tx(char* Tx)
{
	while (*Tx)
	{
		while(!S0TBIR) {}
		S0TBIR =0;
		S0TBUF = *Tx++;
	}
}
		
void main (void)
{
	char R;

	Setup();
	pulse_value = 2300;
	while(1)
	{
		while (!S0RIR)  
		{}
		
		S0RIR = 0;
		R = S0RBUF;
		S0TBUF = R;
		LED4 = !LED4;
		switch (R)
		{
			case 'l':
				Move_Left();
			break;

			case 'r':
				Move_Right();
			break;

			case 'c':
				pulse_value = 1400;
			break;
		}	
				
	}
}