//*****************************************************************************
//
// interrupts.c - Interrupt preemption and tail-chaining example.
//
// Copyright (c) 2005,2006 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 Stellaris Family of microcontroller products.
//
// The software is owned by LMI and/or its suppliers, and is protected under
// applicable copyright laws. All rights are reserved. 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 852 of the Stellaris Driver Library.
//
//*****************************************************************************
#include "hw_ints.h"
#include "hw_memmap.h"
#include "hw_nvic.h"
#include "hw_types.h"
#include "debug.h"
#include "gpio.h"
#include "interrupt.h"
#include "systick.h"
#include "sysctl.h"
#include "../diag.h"
#include "../pdc.h"
//*****************************************************************************
//
//! \addtogroup dk_lm3sxxx_list
//! Interrupts (interrupts)
//!
//! This example application demonstrates the interrupt preemption and
//! tail-chaining capabilities of Cortex-M3 microprocessor and NVIC. Nested
//! interrupts are synthesized when the interrupts have the same priority,
//! increasing priorities, and decreasing priorities. With increasing
//! priorities, preemption will occur; in the other two cases tail-chaining
//! will occur. The currently pending interrupts and the currently executing
//! interrupt will be displayed on the LCD; individual LEDs connected to port
//! B0-B2 will be turned on upon interrupt handler entry and off before
//! interrupt handler exit so that the off-to-on time can be observed with a
//! scope or logic analyzer to see the speed of tail-chaining (for the two
//! cases where tail-chaining is occurring).
//!
//! In order for this example to work properly, the ULED0 (JP22), ULED1 (JP23),
//! and ULED2 (JP24) jumpers must be installed on the board, and the PB1
//! (JP1) jumper on the daughtercard must be set to pins 2 & 3.
//
//*****************************************************************************
//*****************************************************************************
//
// The count of interrupts received. This is incremented as each interrupt
// handler runs, and its value saved into interrupt handler specific values to
// determine the order in which the interrupt handlers were executed.
//
//*****************************************************************************
volatile unsigned long g_ulIndex;
//*****************************************************************************
//
// The value of g_ulIndex when the INT_GPIOA interrupt was processed.
//
//*****************************************************************************
volatile unsigned long g_ulGPIOa;
//*****************************************************************************
//
// The value of g_ulIndex when the INT_GPIOB interrupt was processed.
//
//*****************************************************************************
volatile unsigned long g_ulGPIOb;
//*****************************************************************************
//
// The value of g_ulIndex when the INT_GPIOC interrupt was processed.
//
//*****************************************************************************
volatile unsigned long g_ulGPIOc;
//*****************************************************************************
//
// The error routine that is called if the driver library encounters an error.
//
//*****************************************************************************
#ifdef DEBUG
void
__error__(char *pcFilename, unsigned long ulLine)
{
}
#endif
//*****************************************************************************
//
// Delay for the specified number of seconds. Depending upon the current
// SysTick value, the delay will be between N-1 and N seconds (i.e. N-1 full
// seconds are guaranteed, along with the remainder of the current second).
//
//*****************************************************************************
void
Delay(unsigned long ulSeconds)
{
//
// Loop while there are more seconds to wait.
//
while(ulSeconds--)
{
//
// Wait until the SysTick value is less than 1000.
//
while(SysTickValueGet() > 1000)
{
}
//
// Wait until the SysTick value is greater than 1000.
//
while(SysTickValueGet() < 1000)
{
}
}
}
//*****************************************************************************
//
// Display the interrupt state on the LCD. The currently active and pending
// interrupts are displayed.
//
//*****************************************************************************
void
DisplayIntStatus(void)
{
unsigned long ulTemp;
//
// Display the currently active interrupts.
//
ulTemp = HWREG(NVIC_ACTIVE0);
PDCLCDSetPos(4, 1);
PDCLCDWrite((ulTemp & 1) ? "1" : " ", 1);
PDCLCDWrite((ulTemp & 2) ? "2" : " ", 1);
PDCLCDWrite((ulTemp & 4) ? "3" : " ", 1);
//
// Display the currently pending interrupts.
//
ulTemp = HWREG(NVIC_PEND0);
PDCLCDSetPos(13, 1);
PDCLCDWrite((ulTemp & 1) ? "1" : " ", 1);
PDCLCDWrite((ulTemp & 2) ? "2" : " ", 1);
PDCLCDWrite((ulTemp & 4) ? "3" : " ", 1);
}
//*****************************************************************************
//
// This is the handler for INT_GPIOA. It simply saves the interrupt sequence
// number.
//
//*****************************************************************************
void
IntGPIOa(void)
{
//
// Set PB0 high to indicate entry to this interrupt handler.
//
GPIOPinWrite(GPIO_PORTB_BASE, GPIO_PIN_0, GPIO_PIN_0);
//
// Put the current interrupt state on the LCD.
//
DisplayIntStatus();
//
// Wait two seconds.
//
Delay(2);
//
// Save and increment the interrupt sequence number.
//
g_ulGPIOa = g_ulIndex++;
//
// Set PB0 low to indicate exit from this interrupt handler.
//
GPIOPinWrite(GPIO_PORTB_BASE, GPIO_PIN_0, 0);
}
//*****************************************************************************
//
// This is the handler for INT_GPIOB. It triggers INT_GPIOA and saves the
// interrupt sequence number.
//
//*****************************************************************************
void
IntGPIOb(void)
{
//
// Set PB1 high to indicate entry to this interrupt handler.
//
GPIOPinWrite(GPIO_PORTB_BASE, GPIO_PIN_1, GPIO_PIN_1);
//
// Put the current interrupt state on the LCD.
//
DisplayIntStatus();
//
// Trigger the INT_GPIOA interrupt.
//
HWREG(NVIC_SW_TRIG) = INT_GPIOA - 16;
//
// Put the current interrupt state on the LCD.
//
DisplayIntStatus();
//
// Wait two seconds.
//
Delay(2);
//
// Save and increment the interrupt sequence number.
//
g_ulGPIOb = g_ulIndex++;
//
// Set PB1 low to indicate exit from this interrupt handler.
//
GPIOPinWrite(GPIO_PORTB_BASE, GPIO_PIN_1, 0);
}
//*****************************************************************************
//
// This is the handler for INT_GPIOC. It triggers INT_GPIOB and saves the
// interrupt sequence number.
//
//*****************************************************************************
void
IntGPIOc(void)
{
//
// Set PB2 high to indicate entry to this interrupt handler.
//
GPIOPinWrite(GPIO_PORTB_BASE, GPIO_PIN_2, GPIO_PIN_2);
//
// Put the current interrupt state on the LCD.
//
DisplayIntStatus();
//
// Trigger the INT_GPIOB interrupt.
//
HWREG(NVIC_SW_TRIG) = INT_GPIOB - 16;
//
// Put the current interrupt state on the LCD.
//
DisplayIntStatus();
//
// Wait two seconds.
//
Delay(2);
//
// Save and increment the interrupt sequence number.
//
g_ulGPIOc = g_ulIndex++;
//
// Set PB2 low to indicate exit from this interrupt handler.
//
GPIOPinWrite(GPIO_PORTB_BASE, GPIO_PIN_2, 0);
}
//*****************************************************************************
//
// This is the main example program. It checks to see that the interrupts are
// processed in the correct order when they have identical priorities,
// increasing priorities, and decreasing priorities. This exercises interrupt
// preemption and tail chaining.
//
//*****************************************************************************
int
main(void)
{
unsigned long ulError;
//
// Set the clocking to run directly from the crystal.
//
SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |
SYSCTL_XTAL_6MHZ);
//
// Enable the peripherals used by this example.
//
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);
//
// Init the PDC, and then the LCD, then write the LEDs.
//
PDCInit();
PDCLCDInit();
PDCLCDBacklightOn();
PDCLCDSetPos(0, 1);
PDCLCDWrite("Act: Pend: ", 16);
//
// Configure the first three pins of GPIO port B to be outputs to indicate
// entry/exit of one of the interrupt handlers.
//
GPIODirModeSet(GPIO_PORTB_BASE, GPIO_PIN_0 | GPIO_PIN_1 | GPIO_PIN_2,
GPIO_DIR_MODE_OUT);
GPIOPinWrite(GPIO_PORTB_BASE, GPIO_PIN_0 | GPIO_PIN_1 | GPIO_PIN_2, 0);
//
// Set up and enable the SysTick timer. It will be used as a reference
// for delay loops in the interrupt handlers. The SysTick timer period
// will be set up for one second.
//
SysTickPeriodSet(SysCtlClockGet());
SysTickEnable();
//
// Reset the error indicator.
//
ulError = 0;
//
// Enable interrupts to the processor.
//
IntMasterEnable();
//
// Enable the interrupts.
//
IntEnable(INT_GPIOA);
IntEnable(INT_GPIOB);
IntEnable(INT_GPIOC);
//
// Indicate that the equal interrupt priority test is beginning.
//
PDCLCDSetPos(0, 0);
PDCLCDWrite("Equal Priority ", 16);
//
// Set the interrupt priorities so they are all equal.
//
IntPrioritySet(INT_GPIOA, 0x00);
IntPrioritySet(INT_GPIOB, 0x00);
IntPrioritySet(INT_GPIOC, 0x00);
//
// Reset the interrupt flags.
//
g_ulGPIOa = 0;
g_ulGPIOb = 0;
g_ulGPIOc = 0;
g_ulIndex = 1;
//
// Trigger the interrupt for GPIO C.
//
HWREG(NVIC_SW_TRIG) = INT_GPIOC - 16;
//
// Put the current interrupt state on the LCD.
//
DisplayIntStatus();
//
// Verify that the interrupts were processed in the correct order.
//
if((g_ulGPIOa != 3) || (g_ulGPIOb != 2) || (g_ulGPIOc != 1))
{
ulError |= 1;
}
//
// Wait two seconds.
//
Delay(2);
//
// Indicate that the decreasing interrupt priority test is beginning.
//
PDCLCDSetPos(0, 0);
PDCLCDWrite("Dec. Priority ", 16);
//
// Set the interrupt priorities so that they are decreasing (i.e. C > B >
// A).
//
IntPrioritySet(INT_GPIOA, 0x80);
IntPrioritySet(INT_GPIOB, 0x40);
IntPrioritySet(INT_GPIOC, 0x00);
//
// Reset the interrupt flags.
//
g_ulGPIOa = 0;
g_ulGPIOb = 0;
g_ulGPIOc = 0;
g_ulIndex = 1;
//
// Trigger the interrupt for GPIO C.
//
HWREG(NVIC_SW_TRIG) = INT_GPIOC - 16;
//
// Put the current interrupt state on the LCD.
//
DisplayIntStatus();
//
// Verify that the interrupts were processed in the correct order.
//
if((g_ulGPIOa != 3) || (g_ulGPIOb != 2) || (g_ulGPIOc != 1))
{
ulError |= 2;
}
//
// Wait two seconds.
//
Delay(2);
//
// Indicate that the increasing interrupt priority test is beginning.
//
PDCLCDSetPos(0, 0);
PDCLCDWrite("Inc. Priority ", 16);
//
// Set the interrupt priorities so that they are increasing (i.e. C < B <
// A).
//
IntPrioritySet(INT_GPIOA, 0x00);
IntPrioritySet(INT_GPIOB, 0x40);
IntPrioritySet(INT_GPIOC, 0x80);
//
// Reset the interrupt flags.
//
g_ulGPIOa = 0;
g_ulGPIOb = 0;
g_ulGPIOc = 0;
g_ulIndex = 1;
//
// Trigger the interrupt for GPIO C.
//
HWREG(NVIC_SW_TRIG) = INT_GPIOC - 16;
//
// Put the current interrupt state on the LCD.
//
DisplayIntStatus();
//
// Verify that the interrupts were processed in the correct order.
//
if((g_ulGPIOa != 1) || (g_ulGPIOb != 2) || (g_ulGPIOc != 3))
{
ulError |= 4;
}
//
// Wait two seconds.
//
Delay(2);
//
// Disable the interrupts.
//
IntDisable(INT_GPIOA);
IntDisable(INT_GPIOB);
IntDisable(INT_GPIOC);
//
// Disable interrupts to the processor.
//
IntMasterDisable();
//
// Print out the test results.
//
PDCLCDSetPos(0, 0);
PDCLCDWrite("Int Priority ", 16);
PDCLCDSetPos(0, 1);
if(ulError)
{
PDCLCDWrite("=: P >: P PDCLCDSetPos(3, 1);
PDCLCDWrite((ulError & 1) ? "F" : "P", 1);
PDCLCDSetPos(9, 1);
PDCLCDWrite((ulError & 2) ? "F" : "P", 1);
PDCLCDSetPos(15, 1);
PDCLCDWrite((ulError & 4) ? "F" : "P", 1);
}
else
{
PDCLCDWrite("Success. ", 16);
}
//
// Exit.
//
DiagExit(0);
}
