pwmgen.c

最新版IAR FOR ARM（EWARM）5.11中的代码例子

//*****************************************************************************
//
// pwmgen.c - PWM signal generation example.
//
// Copyright (c) 2005-2007 Luminary Micro, Inc.  All rights reserved.
// 
// Software License Agreement
// 
// Luminary Micro, Inc. (LMI) is supplying this software for use solely and
// exclusively on LMI's microcontroller products.
// 
// The software is owned by LMI and/or its suppliers, and is protected under
// applicable copyright laws.  All rights are reserved.  You may not combine
// this software with "viral" open-source software in order to form a larger
// program.  Any use in violation of the foregoing restrictions may subject
// the user to criminal sanctions under applicable laws, as well as to civil
// liability for the breach of the terms and conditions of this license.
// 
// THIS SOFTWARE IS PROVIDED "AS IS".  NO WARRANTIES, WHETHER EXPRESS, IMPLIED
// OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE.
// LMI SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR
// CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.
// 
// This is part of revision 1952 of the Stellaris Peripheral Driver Library.
//
//*****************************************************************************

#include "../../../hw_memmap.h"
#include "../../../hw_types.h"
#include "../../../src/debug.h"
#include "../../../src/gpio.h"
#include "../../../src/pwm.h"
#include "../../../src/sysctl.h"
#include "../../../utils/diag.h"
#include "../pdc.h"

//*****************************************************************************
//
//! \addtogroup dk_lm3s815_list
//! <h1>PWM (pwmgen)</h1>
//!
//! This example application utilizes the PWM peripheral to output a 25% duty
//! cycle PWM signal and a 75% duty cycle PWM signal, both at 50 kHz.  Once
//! configured, the application enters an infinite loop, doing nothing while
//! the PWM peripheral continues to output its signals.
//
//*****************************************************************************

//*****************************************************************************
//
// 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_6MHZ);
    SysCtlPWMClockSet(SYSCTL_PWMDIV_1);

    //
    // Init the PDC, and then the LCD, then write the LCD.
    //
    PDCInit();
    PDCLCDInit();
    PDCLCDBacklightOn();

    //
    // Clear the screen and thell the user what is happening.
    //
    PDCLCDClear();
    PDCLCDSetPos(1, 0);
    PDCLCDWrite("Generating PWM", 14);
    PDCLCDSetPos(1, 1);
    PDCLCDWrite("on PD0 and PD1", 14);

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

    //
    // Set GPIO D0 and D1 as PWM pins.  They are used to output the PWM0 and
    // PWM1 signals.
    //
    GPIOPinTypePWM(GPIO_PORTD_BASE, GPIO_PIN_0 | GPIO_PIN_1);

    //
    // Compute the PWM period based on the system clock.
    //
    ulPeriod = SysCtlClockGet() / 50000;

    //
    // Set the PWM period to 50 kHz.
    //
    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)
    {
    }
}