Timer interrupt on LM4F120 using TimerIntRegister issue

Bernard · January 15, 2013

Hi,

here is a Timer based blink using TimerIntRegister :

/*****************************
 * LM4F120 - timer based blink 
 * Using TimerIntRegister
 * 80 Mhz clock
 *****************************/

#include "inc/hw_ints.h"
#include "driverlib/interrupt.h"
#include "driverlib/sysctl.h"
#include "driverlib/timer.h"


void initTimer()
{  
  ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0);
  ROM_TimerConfigure(TIMER0_BASE, TIMER_CFG_PERIODIC);   // 32 bits Timer
  TimerIntRegister(TIMER0_BASE, TIMER_A, Timer0Isr);    // Registering  isr       
  ROM_TimerEnable(TIMER0_BASE, TIMER_A); 
  ROM_IntEnable(INT_TIMER0A); 
  ROM_TimerIntEnable(TIMER0_BASE, TIMER_TIMA_TIMEOUT);  
}

void Timer0Isr(void)
{
  ROM_TimerIntClear(TIMER0_BASE, TIMER_TIMA_TIMEOUT);  // Clear the timer interrupt
  digitalWrite(RED_LED, digitalRead(RED_LED) ^ 1);              // toggle LED pin
}

void setup()
{
  Serial.begin(9600);
  pinMode(RED_LED,OUTPUT);
  initTimer();
}

void loop()
{  
  unsigned long ulPeriod;
  unsigned int Hz = 5;   // frequency in Hz  
  ulPeriod = (SysCtlClockGet() / Hz)/ 2;
  ROM_TimerLoadSet(TIMER0_BASE, TIMER_A,ulPeriod -1);
  while (1)
  {
    Serial.println("While timer is running ..."); 
    delay(100);
  }
}

This compiles ok but I don' get the success message and I have to press reset button or sometimes unplug and replug the board to have it working. That means the code is uploaded.

All my other codes compile and upload ok, just a problem with IntRegister ( Timer, Gpio ..)

I am not skilled enough to understand what is going wrong so if someone could test this code and tell me what is it from his part.

I posted the same question on Energia forum ( a mistake ) and I realize it wasn't the right place, I apologize for that.

Regards

Bernard

Bernard · January 25, 2013

Bernard · February 23, 2013

Hi,

I am wondering what is going wrong with me, I must be the most stupid newbie in the ARM world.

Almost 200 views of my topic and no answer to my question ...

Regards

Bernard

energia · March 1, 2013

Not stupid at all. Something is fishy with the way lm4flash uploads to the target. If you comment out "TimerIntRegister(TIMER0_BASE, TIMER_A, Timer0Isr);" then all is well. I can't say anything sensible about what's going on but it seems that there is a bug in lm4flash.

OpenOCD has no problem uploading the .elf file from this Sketch.

I will contact the lm4flash maintainer.

Thanks,

Robert

jkabat · March 1, 2013

Robert,

I wonder if it is a "HOT" interrupt? When I init I always disable and then clear any interrupts I use before setting up my device and interrupt.

Regards

JohnK

Bernard · March 2, 2013

Hi Robert,

Thank you for your comments... looking forward for information.

Bernard

ricardojlrufino · April 28, 2013

I'm having the same problem ...

Does anyone have any solution? Some example using interrupt?

ricardojlrufino · April 28, 2013

I tried to run the example Interruption Stas, successfully compiled and uploaded, however looking at the console, it's like not interrupts execute.

Examble: {StellarisWare_DIR}\boards\ek-lm4f120xl\interrupts

I copied the library that was missing (driverlib the StellarisWar) to the folder:

energia-0101E0009/hardware/lm4f/cores/lm4f

//*****************************************************************************
//
// interrupts.c - Interrupt preemption and tail-chaining example.
//
// Copyright (c) 2012 Texas Instruments Incorporated.  All rights reserved.
// Software License Agreement
// 
// Texas Instruments (TI) is supplying this software for use solely and
// exclusively on TI's microcontroller products. The software is owned by
// TI and/or its suppliers, and is protected under applicable copyright
// laws. You may not combine this software with "viral" open-source
// software in order to form a larger program.
// 
// THIS SOFTWARE IS PROVIDED "AS IS" AND WITH ALL FAULTS.
// 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. TI SHALL NOT, UNDER ANY
// CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
// DAMAGES, FOR ANY REASON WHATSOEVER.
// 
// This is part of revision 9453 of the EK-LM4F120XL Firmware Package.
//
//*****************************************************************************

#include "inc/hw_ints.h"
#include "inc/hw_memmap.h"
#include "inc/hw_nvic.h"
#include "inc/hw_types.h"
#include "driverlib/debug.h"
#include "driverlib/fpu.h"
#include "driverlib/gpio.h"
#include "driverlib/interrupt.h"
#include "driverlib/pin_map.h"
#include "driverlib/rom.h"
#include "driverlib/sysctl.h"
#include "driverlib/systick.h"
#include "utils/uartstdio.h"

//*****************************************************************************
//
//! \addtogroup example_list
//! <h1>Interrupts (interrupts)</h1>
//!
//! This example application demonstrates the interrupt preemption and
//! tail-chaining capabilities of Cortex-M4 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 display; GPIO pins E1, E2 and E3 will
//! be asserted upon interrupt handler entry and de-asserted 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).
//
//*****************************************************************************


//*****************************************************************************
//
// 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(ROM_SysTickValueGet() > 1000)
        {
        }

        //
        // Wait until the SysTick value is greater than 1000.
        //
        while(ROM_SysTickValueGet() < 1000)
        {
        }
    }
}

//*****************************************************************************
//
// Display the interrupt state on the UART.  The currently active and pending
// interrupts are displayed.
//
//*****************************************************************************
void
DisplayIntStatus(void)
{
    unsigned long ulTemp;

    //
    // Display the currently active interrupts.
    //
    ulTemp = HWREG(NVIC_ACTIVE0);
    UARTprintf("\rActive: %c%c%c ", (ulTemp & 1) ? '1' : ' ',
               (ulTemp & 2) ? '2' : ' ', (ulTemp & 4) ? '3' : ' ');

    //
    // Display the currently pending interrupts.
    //
    ulTemp = HWREG(NVIC_PEND0);
    UARTprintf("Pending: %c%c%c", (ulTemp & 1) ? '1' : ' ',
               (ulTemp & 2) ? '2' : ' ', (ulTemp & 4) ? '3' : ' ');
}

//*****************************************************************************
//
// This is the handler for INT_GPIOA.  It simply saves the interrupt sequence
// number.
//
//*****************************************************************************
void
IntGPIOa(void)
{
    //
    // Set PE1 high to indicate entry to this interrupt handler.
    //
    ROM_GPIOPinWrite(GPIO_PORTE_BASE, GPIO_PIN_1, GPIO_PIN_1);

    //
    // Put the current interrupt state on the display.
    //
    DisplayIntStatus();

    //
    // Wait two seconds.
    //
    Delay(2);

    //
    // Save and increment the interrupt sequence number.
    //
    g_ulGPIOa = g_ulIndex++;

    //
    // Set PE1 low to indicate exit from this interrupt handler.
    //
    ROM_GPIOPinWrite(GPIO_PORTE_BASE, GPIO_PIN_1, 0);
}

//*****************************************************************************
//
// This is the handler for INT_GPIOB.  It triggers INT_GPIOA and saves the
// interrupt sequence number.
//
//*****************************************************************************
void
IntGPIOb(void)
{
    //
    // Set PE2 high to indicate entry to this interrupt handler.
    //
    ROM_GPIOPinWrite(GPIO_PORTE_BASE, GPIO_PIN_2, GPIO_PIN_2);

    //
    // Put the current interrupt state on the display.
    //
    DisplayIntStatus();

    //
    // Trigger the INT_GPIOA interrupt.
    //
    HWREG(NVIC_SW_TRIG) = INT_GPIOA - 16;

    //
    // Put the current interrupt state on the display.
    //
    DisplayIntStatus();

    //
    // Wait two seconds.
    //
    Delay(2);

    //
    // Save and increment the interrupt sequence number.
    //
    g_ulGPIOb = g_ulIndex++;

    //
    // Set PE2 low to indicate exit from this interrupt handler.
    //
    ROM_GPIOPinWrite(GPIO_PORTE_BASE, GPIO_PIN_2, 0);
}

//*****************************************************************************
//
// This is the handler for INT_GPIOC.  It triggers INT_GPIOB and saves the
// interrupt sequence number.
//
//*****************************************************************************
void
IntGPIOc(void)
{
    //
    // Set PE3 high to indicate entry to this interrupt handler.
    //
    ROM_GPIOPinWrite(GPIO_PORTE_BASE, GPIO_PIN_3, GPIO_PIN_3);

    //
    // Put the current interrupt state on the display.
    //
    DisplayIntStatus();

    //
    // Trigger the INT_GPIOB interrupt.
    //
    HWREG(NVIC_SW_TRIG) = INT_GPIOB - 16;

    //
    // Put the current interrupt state on the display.
    //
    DisplayIntStatus();

    //
    // Wait two seconds.
    //
    Delay(2);

    //
    // Save and increment the interrupt sequence number.
    //
    g_ulGPIOc = g_ulIndex++;

    //
    // Set PE3 low to indicate exit from this interrupt handler.
    //
    ROM_GPIOPinWrite(GPIO_PORTE_BASE, GPIO_PIN_3, 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;

    //
    // Enable lazy stacking for interrupt handlers.  This allows floating-point
    // instructions to be used within interrupt handlers, but at the expense of
    // extra stack usage.
    //
    ROM_FPULazyStackingEnable();

    //
    // Set the clocking to run directly from the crystal.
    //
    ROM_SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |
                       SYSCTL_XTAL_16MHZ);

    //
    // Enable the peripherals used by this example.
    //
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOE);

    //
    // Initialize the UART.
    //
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
    GPIOPinConfigure(GPIO_PA0_U0RX);
    GPIOPinConfigure(GPIO_PA1_U0TX);
    ROM_GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);
    UARTStdioInit(0);
    UARTprintf("\033[2JInterrupts\n");

    //
    // Configure the PB0-PB2 to be outputs to indicate entry/exit of one
    // of the interrupt handlers.
    //
    ROM_GPIOPinTypeGPIOOutput(GPIO_PORTE_BASE, GPIO_PIN_1 | GPIO_PIN_2 |
                                               GPIO_PIN_3);
    ROM_GPIOPinWrite(GPIO_PORTE_BASE, GPIO_PIN_1 | GPIO_PIN_2 | GPIO_PIN_3, 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.
    //
    ROM_SysTickPeriodSet(ROM_SysCtlClockGet());
    ROM_SysTickEnable();

    //
    // Reset the error indicator.
    //
    ulError = 0;

    //
    // Enable interrupts to the processor.
    //
    ROM_IntMasterEnable();

    //
    // Enable the interrupts.
    //
    ROM_IntEnable(INT_GPIOA);
    ROM_IntEnable(INT_GPIOB);
    ROM_IntEnable(INT_GPIOC);

    //
    // Indicate that the equal interrupt priority test is beginning.
    //
    UARTprintf("\nEqual Priority\n");

    //
    // Set the interrupt priorities so they are all equal.
    //
    ROM_IntPrioritySet(INT_GPIOA, 0x00);
    ROM_IntPrioritySet(INT_GPIOB, 0x00);
    ROM_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.
    //
    UARTprintf("\nDecreasing Priority\n");

    //
    // Set the interrupt priorities so that they are decreasing (i.e. C > B >
    // A).
    //
    ROM_IntPrioritySet(INT_GPIOA, 0x80);
    ROM_IntPrioritySet(INT_GPIOB, 0x40);
    ROM_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 UART.
    //
    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.
    //
    UARTprintf("\nIncreasing Priority\n");

    //
    // Set the interrupt priorities so that they are increasing (i.e. C < B <
    // A).
    //
    ROM_IntPrioritySet(INT_GPIOA, 0x00);
    ROM_IntPrioritySet(INT_GPIOB, 0x40);
    ROM_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 UART.
    //
    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.
    //
    ROM_IntDisable(INT_GPIOA);
    ROM_IntDisable(INT_GPIOB);
    ROM_IntDisable(INT_GPIOC);

    //
    // Disable interrupts to the processor.
    //
    ROM_IntMasterDisable();

    //
    // Print out the test results.
    //
    UARTprintf("\nInterrupt Priority =: %s  >: %s  <: %s\n",
               (ulError & 1) ? "Fail" : "Pass",
               (ulError & 2) ? "Fail" : "Pass",
               (ulError & 4) ? "Fail" : "Pass");

    //
    // Loop forever.
    //
    while(1)
    {
    }
}

Bernard · June 3, 2013

Hi,

Thanks to patolin my problem is solved

ricardojlrufino · July 7, 2013

what is the solution ?

pedroarbs · September 16, 2013

Bernard, can you tell how did you solve your problem or post the source code? Thanks.

holianh · November 5, 2013

I have copyed and complied the TOP source code, but it contain errors: tBoolean.

I defined it in Energia.h, it compile successful, but i can not upload to Stellaris (wait very long time). I dont know why?

thequila · November 6, 2013

@@ricardojlrufino @@pedroarbs

I think this is the answer Bernard was talking about:

http://patolin.com/blog/2013/05/16/stellaris-launchpad-y-energia-programando-un-cortex-m3-facilmente/

energia · April 10, 2014

I just ran the Sketch from @@brownfox as is under Energia 12 and it works like a charm. This turned out to be combination of issues with lm4flash and the linker script.

energia · April 10, 2014

Here is a slightly modified Sketch that works with the latest Driverlib: https://gist.github.com/robertinant/10398194

Timer interrupt on LM4F120 using TimerIntRegister issue

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