crazy PWM

Hi,

I'm having some difficulties with a project I am working on.  I am moving a DC motor bi-directionally at varying PWM duty cycles.  I move in one direction at roughly 50% and another at 25%.  When I reach a sensor I set the duty cycle to zero and disable.  Once in a while, I see that when I sensor gets made, the motor immediately starts moving at 100% (perhaps switch back to GPIO mode as opposed to PWM?)

Code to configure

    //
    // Enable the PWM peripheral block.
    //
	SysCtlPeripheralEnable(SYSCTL_PERIPH_PWM0);

	//
	// Set the PWM Clock frequency
	//
	SysCtlPWMClockSet(SYSCTL_PWMDIV_16);

    //
    // Configure the PWM pins to be controlled by the PWM generators.
    //
    GPIOPinTypePWM(GPIO_PORTA_BASE, GPIO_PIN_6);	/* Takeup */
    GPIOPinTypePWM(GPIO_PORTF_BASE, GPIO_PIN_1);
    GPIOPinTypePWM(GPIO_PORTA_BASE, GPIO_PIN_2);	/* Tamp */
    GPIOPinTypePWM(GPIO_PORTE_BASE, GPIO_PIN_1);

	GPIOPinConfigure(GPIO_PA6_PWM0);	/* Transfer VRef */
	GPIOPinConfigure(GPIO_PF1_PWM1);	/* Transfer VRef */
	GPIOPinConfigure(GPIO_PA2_PWM4);	/* Transfer VRef */
	GPIOPinConfigure(GPIO_PE1_PWM5);	/* Transfer VRef */

    //
    // Initialize all of the PWM generators.
    //
    PWMGenConfigure(PWM0_BASE, PWM_GEN_0, PWM_GEN_MODE_UP_DOWN |
                    PWM_GEN_MODE_NO_SYNC | PWM_GEN_MODE_DBG_STOP);
    PWMGenConfigure(PWM0_BASE, PWM_GEN_1, PWM_GEN_MODE_UP_DOWN |
                    PWM_GEN_MODE_NO_SYNC | PWM_GEN_MODE_DBG_STOP);
    PWMGenConfigure(PWM0_BASE, PWM_GEN_2, PWM_GEN_MODE_UP_DOWN |
                    PWM_GEN_MODE_NO_SYNC | PWM_GEN_MODE_DBG_STOP);
    PWMGenConfigure(PWM0_BASE, PWM_GEN_3, PWM_GEN_MODE_UP_DOWN |
                    PWM_GEN_MODE_NO_SYNC | PWM_GEN_MODE_DBG_STOP);


	PWMGenPeriodSet(PWM0_BASE, PWM_GEN_0, 100);
	PWMGenPeriodSet(PWM0_BASE, PWM_GEN_1, 100);
	PWMGenPeriodSet(PWM0_BASE, PWM_GEN_2, 100);
	PWMGenPeriodSet(PWM0_BASE, PWM_GEN_3, 100);

Here is the code I use when I start my motor

		/* Set the duty cycles */
		PWMPulseWidthSet(PWM0_BASE, PWM_OUT_4, sTamp.iForwardSpeed);
		PWMPulseWidthSet(PWM0_BASE, PWM_OUT_5, sTamp.iReverseSpeed);

	    PWMOutputState(PWM0_BASE, PWM_OUT_4_BIT | PWM_OUT_5_BIT, 1);
	    PWMOutputState(PWM0_BASE,
	    		PWM_OUT_0_BIT | PWM_OUT_1_BIT |
	    		PWM_OUT_2_BIT | PWM_OUT_2_BIT |
	    		PWM_OUT_6_BIT | PWM_OUT_7_BIT, 0);

		/* Start the PWM generator. */
		PWMGenEnable(PWM0_BASE, PWM_GEN_2);

And when I reach my switch I use

		/* Stop the PWM generator. */
		PWMGenDisable(PWM0_BASE, PWM_GEN_2);

		/* Set the duty cycles */
		PWMPulseWidthSet(PWM0_BASE, PWM_OUT_4, 0);
		PWMPulseWidthSet(PWM0_BASE, PWM_OUT_5, 0);

	    PWMOutputState(PWM0_BASE,
	    		PWM_OUT_0_BIT | PWM_OUT_1_BIT |
	    		PWM_OUT_2_BIT | PWM_OUT_3_BIT |
	    		PWM_OUT_4_BIT | PWM_OUT_5_BIT |
	    		PWM_OUT_6_BIT | PWM_OUT_7_BIT, 0);

One strange thing I notice, when I use the ROV, it tells me that the PWM clock is _DIV_1 even though I've configured it to be 16.

any thoughts?