LM4F120的PWM

zgbkdlm

LM4F120的PWM [复制链接]

= =..做了做PWM的实验..翻阅StellarisWare的文档直接奔着Chapter 21 PWM那一章去了,写好代码上电,,没反应,,,调试,,发现进入了系统错误中断...
搞了半天才知道原来LM4F120没有PWM模块,还是得用定时器...晕..

  ROM_SysCtlClockSet(SYSCTL_SYSDIV_2_5 | SYSCTL_USE_PLL | SYSCTL_XTAL_16MHZ |           //80mhz
                       SYSCTL_OSC_MAIN);
  
  SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0);
  SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);
  
  GPIOPinConfigure(GPIO_PF1_T0CCP1);
  GPIOPinTypeTimer(GPIO_PORTF_BASE, GPIO_PIN_1);   //PF1
  
  TimerConfigure(TIMER0_BASE, TIMER_CFG_SPLIT_PAIR|TIMER_CFG_B_PWM);
  TimerLoadSet(TIMER0_BASE, TIMER_B, 50000);
  TimerMatchSet(TIMER0_BASE, TIMER_B, 40000); // PWM
  TimerEnable(TIMER0_BASE, TIMER_B);

一般就是这样启动的了.
但有一个疑问.
输出反相怎么设置?手册上说写TnPWML位设置输出正反相.可是在StellarisWare里面找不到相关的函数啊,,还得自己写寄存器..有大神找到么?

Study_Stellaris

//*****************************************************************************
//
//! Controls the output level.
//!
//! \param ui32Base is the base address of the timer module.
//! \param ui32Timer specifies the timer(s) to adjust; must be one of
//! \b TIMER_A, \b TIMER_B, or \b TIMER_BOTH.
//! \param bInvert specifies the output level.
//!
//! This function configures the PWM output level for the specified timer.  If
//! the \e bInvert parameter is \b true, then the timer's output is made active
//! low; otherwise, it is made active high.
//!
//! \return None.
//
//*****************************************************************************
void
TimerControlLevel(uint32_t ui32Base, uint32_t ui32Timer, bool bInvert)
{
    //
    // Check the arguments.
    //
    ASSERT(_TimerBaseValid(ui32Base));
    ASSERT((ui32Timer == TIMER_A) || (ui32Timer == TIMER_B) ||
           (ui32Timer == TIMER_BOTH));

    //
    // Set the output levels as requested.
    //
    ui32Timer &= TIMER_CTL_TAPWML | TIMER_CTL_TBPWML;
    HWREG(ui32Base + TIMER_O_CTL) = (bInvert ?
                                     (HWREG(ui32Base + TIMER_O_CTL) |
                                      ui32Timer) :
                                     (HWREG(ui32Base + TIMER_O_CTL) &
                                      ~(ui32Timer)));
}