PWM时钟分频出了问题

Yizhou Chen 说：

调了一晚上了，想让pwm输出50hz的周期的pwm来驱动舵机，然而pwm时钟就是不分频。我设置的是16分频，但用pmwclkget函数，返回的是“不分频”，示波器测出来的是800hz，求大家解答。

附上pwm代码

#include"main.h"
#include"duoji.h"
#include"pwm.h"
#include "inc/hw_memmap.h"
#include "driverlib/gpio.h"
#include "driverlib/pin_map.h"
#include "driverlib/pwm.h"
#include "driverlib/sysctl.h"
#include "driverlib/uart.h"

void pwminit(void)
{

SysCtlPeripheralEnable(SYSCTL_PERIPH_PWM0);

PWMClockSet(PWM0_BASE,SYSCTL_PWMDIV_16);

SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);

GPIOPinConfigure(GPIO_PF0_M0PWM0);
GPIOPinConfigure(GPIO_PF1_M0PWM1);

GPIOPinTypePWM(GPIO_PORTF_BASE, GPIO_PIN_0|GPIO_PIN_1);

PWMGenConfigure(PWM0_BASE, PWM_GEN_0, PWM_GEN_MODE_UP_DOWN |
PWM_GEN_MODE_NO_SYNC);

PWMGenPeriodSet(PWM0_BASE, PWM_GEN_0, 20000);

PWMPulseWidthSet(PWM0_BASE, PWM_OUT_0|PWM_OUT_1,
1000);

long aw=PWMGenPeriodGet(PWM0_BASE, PWM_GEN_0);

PWMOutputState(PWM0_BASE, PWM_OUT_0_BIT|PWM_OUT_1_BIT, true);

PWMGenEnable(PWM0_BASE, PWM_GEN_0);

}

//然后main是这样的

int main(void)
{

g_ui32SysClock = MAP_SysCtlClockFreqSet((SYSCTL_XTAL_25MHZ |
SYSCTL_OSC_MAIN |
SYSCTL_USE_PLL |
SYSCTL_CFG_VCO_480), 16000000);

pwminit();
uartinit();

adcinit();
IntEnable(INT_PWM0_0|INT_PWM0_1|INT_UART3);
IntMasterEnable();
while(1)
{


pmwclk2333=PWMClockGet(PWM0_BASE);

}
}

//*****************************************************************************
///
//! Sets the PWM clock configuration.
//!
//! \param ui32Base is the base address of the PWM module.
//! \param ui32Config is the configuration for the PWM clock; it must be one of
//! \b PWM_SYSCLK_DIV_1, \b PWM_SYSCLK_DIV_2, \b PWM_SYSCLK_DIV_4,
//! \b PWM_SYSCLK_DIV_8, \b PWM_SYSCLK_DIV_16, \b PWM_SYSCLK_DIV_32, or
//! \b PWM_SYSCLK_DIV_64.
//!
//! This function sets the PWM clock divider as the PWM clock source. It also
//! configures the clock frequency to the PWM module as a division of the
//! system clock. This clock is used by the PWM module to generate PWM
//! signals; its rate forms the basis for all PWM signals.
//!
//! \note This function should not be used with TM4C123 devices. For
//! TM4C123 devices, the SysCtlPWMClockGet() function should be used.
//!
//! \note The clocking of the PWM is dependent upon the system clock rate as
//! configured by SysCtlClockFreqSet().
//!
//! \return None.
//
//*****************************************************************************

注意红色字体部分，TM4C123需要使用SysCtlPWMClockGet() 

所以不清楚你是使用哪个具体物料？