pwm问题

cylot

pwm问题 [复制链接]

我对lm3s6965例程里的pwm例程把PD1改PE1，结果PE1输出低电平，而没改之前PD1输出对应的是喇叭，高电平有效，一下是原厂提供的程序
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/debug.h"
#include "driverlib/gpio.h"
#include "driverlib/pwm.h"
#include "driverlib/sysctl.h"
#include "drivers/rit128x96x4.h"

//*****************************************************************************
//
// The error routine that is called if the driver library encounters an error.
//
//*****************************************************************************
#ifdef DEBUG
void
__error__(char *pcFilename, unsigned long ulLine)
{
}
#endif

//*****************************************************************************
//
// This example demonstrates how to setup the PWM block to generate signals.
//
//*****************************************************************************
int
main(void)
{
    unsigned long ulPeriod;

    //
    // Set the clocking to run directly from the crystal.
    //
    SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |
                   SYSCTL_XTAL_8MHZ);
    SysCtlPWMClockSet(SYSCTL_PWMDIV_1);

    //
    // Initialize the OLED display.
    //
    RIT128x96x4Init(1000000);

    //
    // Clear the screen and tell the user what is happening.
    //
    RIT128x96x4StringDraw("Generating PWM", 18, 24, 15);
    RIT128x96x4StringDraw("on PF0 and PD1", 18, 32, 15);

    //
    // Enable the peripherals used by this example.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_PWM);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);

    //
    // Set GPIO F0 and D1 as PWM pins.  They are used to output the PWM0 and
    // PWM1 signals.
    //
    GPIOPinTypePWM(GPIO_PORTF_BASE, GPIO_PIN_0);
    GPIOPinTypePWM(GPIO_PORTD_BASE, GPIO_PIN_1);

    //
    // Compute the PWM period based on the system clock.
    //
    ulPeriod = SysCtlClockGet() / 440;

    //
    // Set the PWM period to 440 (A) Hz.
    //
    PWMGenConfigure(PWM_BASE, PWM_GEN_0,
                    PWM_GEN_MODE_UP_DOWN | PWM_GEN_MODE_NO_SYNC);
    PWMGenPeriodSet(PWM_BASE, PWM_GEN_0, ulPeriod);

    //
    // Set PWM0 to a duty cycle of 25% and PWM1 to a duty cycle of 75%.
    //
    PWMPulseWidthSet(PWM_BASE, PWM_OUT_0, ulPeriod / 4);
    PWMPulseWidthSet(PWM_BASE, PWM_OUT_1, ulPeriod * 3 / 4);

    //
    // Enable the PWM0 and PWM1 output signals.
    //
    PWMOutputState(PWM_BASE, PWM_OUT_0_BIT | PWM_OUT_1_BIT, true);

    //
    // Enable the PWM generator.
    //
    PWMGenEnable(PWM_BASE, PWM_GEN_0);

    //
    // Loop forever while the PWM signals are generated.
    //
    while(1)
    {
    }
}
我只把上面程序中的GPIOD改为GPIOE，结果PE1输出低电平，把PWM_OUT_1改为PWM_OUT_5也是低电平，（注：PE1对应的是pwm5），希望各位高手给小弟解答啊。我对这个程序不了解，拜托了，详细点

academic

把改过的程序也贴上来吧，这样才知道具体改哪里了

cylot

#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/debug.h"
#include "driverlib/gpio.h"
#include "driverlib/pwm.h"
#include "driverlib/sysctl.h"
#include "drivers/rit128x96x4.h"
//*****************************************************************************
#ifdef DEBUG
void
__error__(char *pcFilename, unsigned long ulLine)
{
}
#endif

//*****************************************************************************
//
// This example demonstrates how to setup the PWM block to generate signals.
//
//*****************************************************************************
int
main(void)
{
    unsigned long ulPeriod;

    //
    // Set the clocking to run directly from the crystal.
    //
    SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |
                   SYSCTL_XTAL_8MHZ);
    SysCtlPWMClockSet(SYSCTL_PWMDIV_1);

    //
    // Initialize the OLED display.
    //
    RIT128x96x4Init(1000000);

    //
    // Clear the screen and tell the user what is happening.
    //
    RIT128x96x4StringDraw("Generating PWM", 18, 24, 15);
    RIT128x96x4StringDraw("on PF0 and PD1", 18, 32, 15);

    //
    // Enable the peripherals used by this example.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_PWM);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOE);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);

    //
    // Set GPIO F0 and D1 as PWM pins.  They are used to output the PWM0 and
    // PWM1 signals.
    //
    GPIOPinTypePWM(GPIO_PORTF_BASE, GPIO_PIN_0);
    GPIOPinTypePWM(GPIO_PORTE_BASE, GPIO_PIN_1);

    //
    // Compute the PWM period based on the system clock.
    //
    ulPeriod = SysCtlClockGet() / 440;

    //
    // Set the PWM period to 440 (A) Hz.
    //
    PWMGenConfigure(PWM_BASE, PWM_GEN_0,
                    PWM_GEN_MODE_UP_DOWN | PWM_GEN_MODE_NO_SYNC);
    PWMGenPeriodSet(PWM_BASE, PWM_GEN_0, ulPeriod);

    //
    // Set PWM0 to a duty cycle of 25% and PWM1 to a duty cycle of 75%.
    //
    PWMPulseWidthSet(PWM_BASE, PWM_OUT_0, ulPeriod / 4);
    PWMPulseWidthSet(PWM_BASE, PWM_OUT_1, ulPeriod * 3 / 4);

    //
    // Enable the PWM0 and PWM1 output signals.
    //
    PWMOutputState(PWM_BASE, PWM_OUT_0_BIT | PWM_OUT_1_BIT, true);

    //
    // Enable the PWM generator.
    //
    PWMGenEnable(PWM_BASE, PWM_GEN_0);

    //
    // Loop forever while the PWM signals are generated.
    //
    while(1)
    {
    }
}

academic

PE1 对应的是 PWM5，你还从 PWM_OUT_1 输出是不对的，
PWMPulseWidthSet(PWM_BASE, PWM_OUT_1, ulPeriod * 3 / 4);
不过，我不知道 PWM 发生器0 是不是可以输出到 PWM_OUT_5，你试一下，把  PWM_OUT_1 改成  PWM_OUT_5，看行不？

cylot

这个1改成5我改过了，我在1楼说过啦，还是不行的，pwm发生器0不能输出到PWM_OUT_5，感谢2楼的耐心解答，谢谢

academic

PWMOutputState(PWM_BASE, PWM_OUT_0_BIT | PWM_OUT_1_BIT, true);
这里改了没

cylot

因为pwm发生器0只能产生pwm0和pwm1，所以不能输出pwm5，我之前看datasheet不怎么会，非常感谢，现在可以了 感谢2楼

soso

原帖由 cylot 于 2011-4-10 17:10 发表
因为pwm发生器0只能产生pwm0和pwm1，所以不能输出pwm5，我之前看datasheet不怎么会，非常感谢，现在可以了 感谢2楼

也谢谢你的分享

winthony

没经验，等着牛人解答，呵呵