[求助] pwm问题

cylot 2011-4-8 17:01 楼主

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

回复评论（8）

沙发 academic

回复楼主 cylot 的帖子

把改过的程序也贴上来吧，这样才知道具体改哪里了

点赞 2011-4-8 17:07

板凳 cylot

回复沙发 academic 的帖子

#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)
{
}
}

点赞 2011-4-8 17:14

4楼 academic

回复板凳 cylot 的帖子

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？

点赞 2011-4-8 18:00