使用WTIMER4输出PWM

各位好，由于硬件设计将PWM接在WTIME4的PD4/PD5接口，按照配置普通TIMER的PWM模式测试，发现寄存器的值有变化，但是使用示波器不能检测到PWM波形，请各位指点。

//PWM
#define PWM0_PORT_CLK              SYSCTL_PERIPH_GPIOB
#define PWM0_TIMER_PERIPH_CLK      SYSCTL_PERIPH_TIMER2
#define PWM0_TIMER_BASE            TIMER2_BASE
#define PWM0_PORT_BASE             GPIO_PORTB_BASE
#define PWM0_PORT_PIN              GPIO_PIN_0
#define PWM0_TIMER_CHL             TIMER_A
#define PWM0_TIMER_PIN             GPIO_PB0_T2CCP0
#define PWM12_PORT_CLK             SYSCTL_PERIPH_GPIOD
#define PWM12_TIMER_PERIPH_CLK     SYSCTL_PERIPH_WTIMER4
#define PWM12_TIMER_BASE           WTIMER4_BASE
#define PWM12_PORT_BASE            GPIO_PORTD_BASE
#define PWM1_PORT_PIN      				 GPIO_PIN_4
#define PWM2_PORT_PIN							 GPIO_PIN_5
#define PWM1_TIMER_CHL             TIMER_A
#define PWM2_TIMER_CHL             TIMER_B
#define PWM1_TIMER_PIN             GPIO_PD4_WT4CCP0
#define PWM2_TIMER_PIN             GPIO_PD5_WT4CCP1



void TimerPWMInit(uint32_t prescale,uint32_t loadValue)
{
	SysCtlPeripheralEnable(PWM0_PORT_CLK);
	SysCtlPeripheralEnable(PWM12_PORT_CLK);
	SysCtlPeripheralEnable(PWM0_TIMER_PERIPH_CLK);
	SysCtlPeripheralEnable(PWM12_TIMER_PERIPH_CLK);	
//开启时钟	
	TimerConfigure(PWM0_TIMER_BASE,TIMER_CFG_SPLIT_PAIR | TIMER_CFG_A_PWM);
	TimerConfigure(PWM12_TIMER_BASE,TIMER_CFG_SPLIT_PAIR | TIMER_CFG_A_PWM | TIMER_CFG_B_PWM);
	
	TimerClockSourceSet(PWM0_TIMER_BASE,TIMER_CLOCK_SYSTEM);
	TimerClockSourceSet(PWM12_TIMER_BASE,TIMER_CLOCK_SYSTEM);
	
	TimerControlLevel(PWM0_TIMER_BASE,TIMER_A,true);
	TimerControlLevel(PWM12_TIMER_BASE,TIMER_BOTH,true);
	
	TimerPrescaleSet(PWM0_TIMER_BASE,TIMER_A,prescale);
	TimerPrescaleSet(PWM12_TIMER_BASE,TIMER_BOTH,prescale);
	
	GPIOPinConfigure(PWM0_TIMER_PIN);
	GPIOPinConfigure(PWM1_TIMER_PIN);
	GPIOPinConfigure(PWM2_TIMER_PIN);
	
	GPIOPinTypeTimer(PWM0_PORT_BASE,PWM0_PORT_PIN);
	GPIOPinTypeTimer(PWM12_PORT_BASE,PWM1_PORT_PIN);
	GPIOPinTypeTimer(PWM12_PORT_BASE,PWM2_PORT_PIN);
	
	TimerLoadSet(PWM0_TIMER_BASE,TIMER_A,loadValue);
	TimerLoadSet(PWM12_TIMER_BASE,TIMER_BOTH,loadValue);
	
	TimerEnable(PWM0_TIMER_BASE,TIMER_A);
	TimerEnable(PWM12_TIMER_BASE,TIMER_BOTH);
}