同样配置Timer1的通道1,2,3为PWM输出，
PERCFG &= ~0x40;
P0DIR |= 0x38;
P0SEL |= 0x38;
T1CTL &= ~0x03;
T1CNTL = 0x0;
TIMIF &= ~0x40;
T1CTL |= 0x02;
T1CTL |= 0x8;
T1CCTL1 &= ~0x40;
T1CCTL1 |= 0x04;
T1CCTL1 |= 5<<2;
程序执行到此，P0-3口是低电平，与预期相符； 但程序改为：
PERCFG &= ~0x40;
P0DIR |= 0x38;
P0SEL |= 0x38;
T1CTL &= ~0x03;
T1CNTL = 0x0;
TIMIF &= ~0x40;
T1CTL |= 0x02;
T1CTL |= 0x8;
T1CCTL2 &= ~0x40;
T1CCTL2 |= 0x04;
T1CCTL2 |= 5<<2; 时，P0_4有约8Hz的方波输出， 请问这是何原因导致？
