2530输出方波

请问我想用你所给的代码输出pwm到P1_3，那么我如何修改使得Timer3输出pwm到通道0即P1_3呢？

  PERCFG &= (~(0x20)); // Select Timer 3 Alternative 1 location
  P2SEL |=0x20;
  P2DIR |= 0xC0;  // Give priority to Timer 1 channel2-3
  P1SEL |= BV(4);  // Set P1_4 to peripheral, Timer 1,channel 2
  P1DIR |= BV(4);

  T3CTL &= ~0x10;             // Stop timer 3 (if it was running)
  T3CTL |= 0x04;              // Clear timer 3
  T3CTL &= ~0x08;             // Disable Timer 3 overflow interrupts
  T3CTL |= 0x03;              // Timer 3 mode = 3 - Up/Down

  T3CCTL1 &= ~0x40;           // Disable channel 0 interrupts
  T3CCTL1 |= 0x04;            // Ch0 mode = compare
  T3CCTL1 |= 0x10;            // Ch0 output compare mode = toggle on compare

  T3CTL &= ~0xE0;   // Clear Prescaler divider value
  T3CTL |= 0xA0;    //Set Prescaler divider value = Tick frequency /32
  T3CC0 = 128;      //Set ticks = 128

  // Start timer
  T3CTL |= 0x10;

你好，我使用了以下的程序，但是得出的波形不是我想要的4khz的方波，请问哪里需要改进吗，非常感谢！

void pwmoutput( void )
{
  PERCFG &= (~(0x20)); 
  P2SEL |=0x20;	
  P2DIR |= 0xC0;  	
  P1SEL |= BV(3);  // Set P1_3 to peripheral, Timer 1,channel 2
  P1DIR |= BV(3);	

  T3CTL &= ~0x10;             // Stop timer 3 (if it was running)
  T3CTL |= 0x04;              // Clear timer 3
  T3CTL &= ~0x08;             // Disable Timer 3 overflow interrupts
  T3CTL |= 0x03;              // Timer 3 mode = 3 - Up/Down

  T3CCTL0 &= ~0x40;           // Disable channel 0 interrupts
  T3CCTL0 |= 0x04;            // Ch0 mode = compare
  T3CCTL0 |= 0x10;            // Ch0 output compare mode = toggle on compare

  T3CTL &= ~0xE0;   // Clear Prescaler divider value
  T3CTL |= 0xA0;    //Set Prescaler divider value = Tick frequency /32
  T3CC0 = 128;      //Set ticks = 128

  // Start timer
  T3CTL |= 0x10;
}