gpio_jtag.c

最新版IAR FOR ARM（EWARM）5.11中的代码例子

//*****************************************************************************
//
// gpio_jtag.c - Example to demonstrate recovering the JTAG interface.
//
// Copyright (c) 2006-2007 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_gpio.h"
#include "../../../hw_ints.h"
#include "../../../hw_memmap.h"
#include "../../../hw_types.h"
#include "../../../src/debug.h"
#include "../../../src/gpio.h"
#include "../../../src/interrupt.h"
#include "../../../src/sysctl.h"
#include "../osram128x64x4.h"

//*****************************************************************************
//
//! \addtogroup ek_lm3s6965_list
//! <h1>GPIO JTAG Recovery (gpio_jtag)</h1>
//!
//! This example demonstrates changing the JTAG pins into GPIOs, along with a
//! mechanism to revert them to JTAG pins.  When first run, the pins remain in
//! JTAG mode.  Pressing the select push button will toggle the pins between
//! JTAG mode and GPIO mode.  Because there is no debouncing of the push button
//! (either in hardware or software), a button press will occasionally result
//! in more than one mode change.
//!
//! In this example, all five pins (PB7, PC0, PC1, PC2, and PC3) are switched,
//! though the more typical use would be to change PB7 into a GPIO.
//
//*****************************************************************************

//*****************************************************************************
//
// The current mode of pins PB7, PC0, PC1, PC2, and PC3.  When zero, the pins
// are in JTAG mode; when non-zero, the pins are in GPIO mode.
//
//*****************************************************************************
volatile unsigned long g_ulMode;

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

//*****************************************************************************
//
// The interrupt handler for the PF1 pin interrupt.  When triggered, this will
// toggle the JTAG pins between JTAG and GPIO mode.
//
//*****************************************************************************
void
GPIOFIntHandler(void)
{
    //
    // Clear the GPIO interrupt.
    //
    GPIOPinIntClear(GPIO_PORTF_BASE, GPIO_PIN_1);

    //
    // Toggle the pin mode.
    //
    g_ulMode ^= 1;

    //
    // See if the pins should be in JTAG or GPIO mode.
    //
    if(g_ulMode == 0)
    {
        //
        // Change PB7 and PC0-3 into hardware (i.e. JTAG) pins.
        //
        HWREG(GPIO_PORTB_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;
        HWREG(GPIO_PORTB_BASE + GPIO_O_CR) = 0x80;
        HWREG(GPIO_PORTB_BASE + GPIO_O_AFSEL) |= 0x80;
        HWREG(GPIO_PORTB_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;
        HWREG(GPIO_PORTB_BASE + GPIO_O_CR) = 0x00;
        HWREG(GPIO_PORTB_BASE + GPIO_O_LOCK) = 0;
        HWREG(GPIO_PORTC_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;
        HWREG(GPIO_PORTC_BASE + GPIO_O_CR) = 0x01;
        HWREG(GPIO_PORTC_BASE + GPIO_O_AFSEL) |= 0x01;
        HWREG(GPIO_PORTC_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;
        HWREG(GPIO_PORTC_BASE + GPIO_O_CR) = 0x02;
        HWREG(GPIO_PORTC_BASE + GPIO_O_AFSEL) |= 0x02;
        HWREG(GPIO_PORTC_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;
        HWREG(GPIO_PORTC_BASE + GPIO_O_CR) = 0x04;
        HWREG(GPIO_PORTC_BASE + GPIO_O_AFSEL) |= 0x04;
        HWREG(GPIO_PORTC_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;
        HWREG(GPIO_PORTC_BASE + GPIO_O_CR) = 0x08;
        HWREG(GPIO_PORTC_BASE + GPIO_O_AFSEL) |= 0x08;
        HWREG(GPIO_PORTC_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;
        HWREG(GPIO_PORTC_BASE + GPIO_O_CR) = 0x00;
        HWREG(GPIO_PORTC_BASE + GPIO_O_LOCK) = 0;
    }
    else
    {
        //
        // Change PB7 and PC0-3 into GPIO inputs.
        //
        HWREG(GPIO_PORTB_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;
        HWREG(GPIO_PORTB_BASE + GPIO_O_CR) = 0x80;
        HWREG(GPIO_PORTB_BASE + GPIO_O_AFSEL) &= ~0x7f;
        HWREG(GPIO_PORTB_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;
        HWREG(GPIO_PORTB_BASE + GPIO_O_CR) = 0x00;
        HWREG(GPIO_PORTB_BASE + GPIO_O_LOCK) = 0;
        HWREG(GPIO_PORTC_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;
        HWREG(GPIO_PORTC_BASE + GPIO_O_CR) = 0x01;
        HWREG(GPIO_PORTC_BASE + GPIO_O_AFSEL) &= ~0xfe;
        HWREG(GPIO_PORTC_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;
        HWREG(GPIO_PORTC_BASE + GPIO_O_CR) = 0x02;
        HWREG(GPIO_PORTC_BASE + GPIO_O_AFSEL) &= 0xfd;
        HWREG(GPIO_PORTC_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;
        HWREG(GPIO_PORTC_BASE + GPIO_O_CR) = 0x04;
        HWREG(GPIO_PORTC_BASE + GPIO_O_AFSEL) &= 0xfb;
        HWREG(GPIO_PORTC_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;
        HWREG(GPIO_PORTC_BASE + GPIO_O_CR) = 0x08;
        HWREG(GPIO_PORTC_BASE + GPIO_O_AFSEL) &= 0xf7;
        HWREG(GPIO_PORTC_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;
        HWREG(GPIO_PORTC_BASE + GPIO_O_CR) = 0x00;
        HWREG(GPIO_PORTC_BASE + GPIO_O_LOCK) = 0;
        GPIOPinTypeGPIOInput(GPIO_PORTB_BASE, GPIO_PIN_7);
        GPIOPinTypeGPIOInput(GPIO_PORTC_BASE, (GPIO_PIN_0 | GPIO_PIN_1 |
                                               GPIO_PIN_2 | GPIO_PIN_3));
    }
}

//*****************************************************************************
//
// Toggle the JTAG pins between JTAG and GPIO mode with a push button selecting
// between the two.
//
//*****************************************************************************
int
main(void)
{
    unsigned long ulMode;

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

    //
    // Enable the peripherals used by this application.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOC);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);

    //
    // Configure the push button as an input and enable the pin to interrupt on
    // the falling edge (i.e. when the push button is pressed).
    //
    GPIOPinTypeGPIOInput(GPIO_PORTF_BASE, GPIO_PIN_1);
    GPIOPadConfigSet(GPIO_PORTF_BASE, GPIO_PIN_1, GPIO_STRENGTH_2MA,
                     GPIO_PIN_TYPE_STD_WPU);
    GPIOIntTypeSet(GPIO_PORTF_BASE, GPIO_PIN_1, GPIO_FALLING_EDGE);
    GPIOPinIntEnable(GPIO_PORTF_BASE, GPIO_PIN_1);
    IntEnable(INT_GPIOF);

    //
    // Set the global and local indicator of pin mode to zero, meaning JTAG.
    //
    g_ulMode = 0;
    ulMode = 0;

    //
    // Initialize the OLED display.
    //
    OSRAM128x64x4Init(1000000);
    OSRAM128x64x4StringDraw("PB7/PC0-3 are", 30, 16, 15);
    OSRAM128x64x4StringDraw("JTAG", 48, 32, 15);

    //
    // Loop forever.  This loop simply exists to display on the OLED display
    // the current state of PB7/PC0-3; the handling of changing the JTAG pins
    // to and from GPIO mode is done in GPIO Interrupt Handler.
    //
    while(1)
    {
        //
        // Wait until the pin mode changes.
        //
        while(g_ulMode == ulMode)
        {
        }

        //
        // Save the new mode locally so that a subsequent pin mode change can
        // be detected.
        //
        ulMode = g_ulMode;

        //
        // See what the new pin mode was changed to.
        //
        if(ulMode == 0)
        {
            //
            // Indicate that PB7 and PC0-3 are currently JTAG pins.
            //
            OSRAM128x64x4StringDraw("JTAG", 48, 32, 15);
        }
        else
        {
            //
            // Indicate that PB7 and PC0-3 are currently GPIO pins.
            //
            OSRAM128x64x4StringDraw("GPIO", 48, 32, 15);
        }
    }
}