定时器产生PWM的波形问题

ROM_SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN | SYSCTL_XTAL_25MHZ);

    // System clock is the osc clock   16MHz

IntMasterEnable();

ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER1);                  //PE4选为Timer 1

ROM_GPIOPinTypeTimer(GPIO_PORTE_BASE,GPIO_PIN_4);          

ROM_TimerDisable(TIMER1_BASE,TIMER_B);

ROM_TimerConfigure(TIMER1_BASE,(TIMER_CFG_SPLIT_PAIR | TIMER_CFG_B_PWM | TIMER_CFG_B_PERIODIC));

TimerLoadSet(TIMER1_BASE,TIMER_B,8);

ROM_TimerMatchSet(TIMER2_BASE,TIMER_B,4);

ROM_TimerEnable(TIMER1_BASE,TIMER_B);  

系统时钟为外部的16MHz，PE4 口能不能输出2MHz  占空比为1:1的时钟信号了？  芯片为LM3S9B96

请各位指点下。初学ARM。