Jump to content
43oh

TI-RTOS - MSP432 TimerA initiated multiple channel conversion with the ADC14

frohro

By frohro,
in Energia - MSP

 Share Followers 0

Recommended Posts

frohro

frohro 0

Posted
Posted

Hi,

I'm trying to do a timerA initiated multiple channel conversion with the ADC14 in an MSP432.  It seems that TI-RTOS wants to use all the TimerA modules.  I believe this because I see the TAxR value stop.  I also made a simple timer routine to blink the LED in the TA0 ISR, and it works sometimes and not others.  I notice that there doesn't seem to be any drivers for TI-RTOS for the timers, and no example code for doing a multichannel convert triggered by TimerAx.  I have bare metal code for driverlib that works perfectly, but when I put it into Energia, I get no interrupts, as the timer is stopped.  I can fight with TI-RTOS, and keep starting the timer in my loop(), but of course it isn't sampling at the rate I want then.  I am wondering if perhaps I change the Times_NumberofTimerDevices to be one less, if I could use TimerA3.  What do you all think?  See for example Timer.c below: 

/*
 * Copyright (c) 2014-2016, Texas Instruments Incorporated
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * *  Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * *  Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * *  Neither the name of Texas Instruments Incorporated nor the names of
 *    its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
/*
 *  ======== Timer.c ========
 *
 */
#include <xdc/std.h>
#include <xdc/runtime/Error.h>
#include <xdc/runtime/Assert.h>
#include <xdc/runtime/Startup.h>
#include <xdc/runtime/Types.h>

#include <ti/sysbios/BIOS.h>

#include <ti/sysbios/family/arm/m3/Hwi.h>
#include <ti/sysbios/family/arm/msp432/ClockFreqs.h>

/* TODO: move this peripheral register definition to catalog? */
typedef volatile struct ti_catalog_msp432_peripherals_timers_TimerRegs {
    UInt16 control;
    UInt16 cctl_0;
    UInt16 cctl_1;
    UInt16 cctl_2;
    UInt16 cctl_3;
    UInt16 cctl_4;
    UInt16 cctl_5;
    UInt16 cctl_6;
    UInt16 count;
    UInt16 cc_compare_0;
    UInt16 cc_compare_1;
    UInt16 cc_compare_2;
    UInt16 cc_compare_3;
    UInt16 cc_compare_4;
    UInt16 cc_compare_5;
    UInt16 cc_compare_6;
    UInt16 expansion;
    UInt16 reserved[6];
    UInt16 vector;
} ti_catalog_msp432_peripherals_timers_TimerRegs;

#include "package/internal/Timer.xdc.h"

#define MC           0x0020        /* mode, control = continous up counting */
#define TxCLR        0x0004        /* clear timer counter */
#define CCIE         0x0010        /* compare interrupt enable */
#define CCIFG        0x0001        /* compare interrupt pending flag */
#define TSSEL        0x0100        /* source select = ACLK */
#define ID_MASK      0x00C0        /* input divider bit mask */

#define TIMER_CONTROL_START           MC
#define TIMER_CONTROL_CLEAR           TxCLR
#define TIMER_CONTROL_DEFAULT         TSSEL
#define TIMER_COMPARE_INTR_ENABLE     CCIE
#define TIMER_COMPARE_INTR_PENDING    CCIFG

#define TIMER_DELETED       0
#define BAD_TIMER_ID        1
#define NO_TIMER_AVAIL      2
#define NO_HWI_OBJ          3
#define BAD_PERIOD          4

#define READ_LATENCY                    10   /* # MCLK cycles to allow for
                                                back-to-back read of count */

#define SYS_PERI_HALTCTL_REG    0xE004300C   /* peripheral halt control reg */
#define REG(x)  (*((volatile unsigned *)(x)))

/*
 *  ======== Timer_getAvailMask ========
 */
UInt Timer_getAvailMask()
{
    return (Timer_module->availMask);
}

/*
 *  ======== Timer_getNumTimers ========
 *  Get number of timer peripherals available on the device.
 */
UInt Timer_getNumTimers()
{
    return (Timer_numTimerDevices);
}

/*
 *  ======== Timer_getStatus ========
 *  Get the FREE/INUSE status of the timer.
 */
Timer_Status Timer_getStatus(UInt timerId)
{
    Assert_isTrue(timerId < Timer_numTimerDevices, NULL);

    if (Timer_module->availMask & (0x1 << timerId)) {
        return (Timer_Status_FREE);
    }
    else {
        return (Timer_Status_INUSE);
    }
}

/*
 *  ======== Timer_getMaxTicks ========
 */
UInt32 Timer_getMaxTicks(Timer_Object *obj)
{
    return (0x0000FFFF / obj->period);
}

/*
 *  ======== Timer_setAvailMask ========
 */
Bool Timer_setAvailMask(UInt mask)
{
    UInt i;
    UInt key;
    UInt tmpMask;

    key = Hwi_disable();
    tmpMask = mask;
    for (i = 0; i < Timer_numTimerDevices; i++) {
        /* Check if mask is setting any currently used timer as available */
        if ((tmpMask & 0x1) && (Timer_module->handles[i] != NULL)) {
            Hwi_restore(key);
            return (FALSE);
        }
        tmpMask = tmpMask >> 1;
    }
    Timer_module->availMask = mask;
    Hwi_restore(key);

    return (TRUE);
}

/*
 *  ======== Timer_setNextTick ========
 *  Program the timer's interrupt threshold for the next tick.
 */
Void Timer_setNextTick(Timer_Object *obj, UInt32 ticks)
{
    ti_catalog_msp432_peripherals_timers_TimerRegs *timer;
    UInt32 newPeriod = obj->period * ticks;
    UInt next;
    UInt previous;
    UInt now;

    /* get timer base address */
    timer = (ti_catalog_msp432_peripherals_timers_TimerRegs *)
        Timer_module->device[obj->id].baseAddr;

    previous = obj->prevThreshold;

    /* next is relative to savedCurrCount */
    next = obj->savedCurrCount + newPeriod;

    /* set the compare threshold for next interrupt */
    timer->cc_compare_0 = next;

    /*
     * MSP432 timers will only interrupt if the timer counts *to* the threshold.
     * So we must check to make sure that the threshold wasn't set too late -
     * if it was set late, the timer count will need to wrap before the next
     * interrupt is triggered.  To avoid this, after writing the next
     * interrupt threshold, we read the current count, and if the interrupt
     * threshold was set too late per the current count, we again write
     * to the timer to trigger an immediate interrupt.
     *
     * For the cases where the 'next' threshold is more than the 'previous',
     * the timer will not wrap before the next target tick interrupt.  This
     * creates three regions shown below (A, B, C), where the current 'now'
     * count will reside:
     *
     *  FFFF |                  -
     *       |                  B
     *       |<----- next       -
     *       |                  A
     *       |<----- previous   -
     *       |                  C
     *    0  |                  -
     *
     * A - 'now' is greater than equal to 'previous', and less than 'next':
     * this is the 'normal' region, where the threshold has been set before the
     * next threshold, and no adjustment is needed.
     *
     * B - 'now' is greater than equal to 'next': the threshold was set
     * late, trigger an interrupt now.
     *
     * C - 'now' is less than 'previous': the threshold was set late, trigger
     * an interrupt now.
     *
     * For the cases where the 'next' threshold is less than the 'previous',
     * the timer count is expected to wrap before the next tick interrupt.
     * This creates the three regions shown below (D, E, F), where the current
     * 'now' count will reside:
     *
     *  FFFF |                  -
     *       |                  D
     *       |<----- previous   -
     *       |                  F
     *       |<----- next       -
     *       |                  E
     *    0  |                  -
     *
     * D - 'now' is greater than equal to 'previous': this is a 'normal'
     * region, where the threshold has been set before the next threshold,
     * and no adjustment is needed.
     *
     * E - 'now' is less than 'next': this is another 'normal' region,
     * where the threshold has been set early enough, and no adjustment is
     * needed.
     *
     * F - 'now' is greater than or equal to 'next' and less than
     * 'previous': the threshold was set too late, trigger an interrupt now.
     */

    /* get current timer count */
    now = Timer_getCount(obj);

    /* if not expecting wrap thru zero ... */
    if (next > previous) {

        /* case "B": now is greater than or equal to next, interrupt now */
        if (now >= next) {
            timer->cctl_0 |= CCIFG;
        }

        /* case "C": now < previous, count has wrapped, interrupt now */
        else {
            if (now < previous) {
                timer->cctl_0 |= CCIFG;
            }
        }
    }

    /* else, expecting wrapping thru zero ... */
    else {

        /* case F: now is between next and previous, interrupt now */
        if ((now < previous) && (now >= next)) {
            timer->cctl_0 |= CCIFG;
        }
    }
}

/*
 *  ======== Timer_Module_startup ========
 *  Calls postInit for all statically-created & constructed
 *  timers to initialize them.
 */
Int Timer_Module_startup(Int status)
{
    Int i;
    Timer_Object *obj;

    if (Timer_startupNeeded) {
        for (i = 0; i < Timer_numTimerDevices; i++) {
            obj = Timer_module->handles[i];
            /* if timer was statically created/constructed */
            if ((obj != NULL) && (obj->staticInst)) {
                Timer_postInit(obj, NULL);
            }
        }
    }

    return (Startup_DONE);
}

/*
 *  ======== Timer_startup ========
 *  Here after call to main().  Called from BIOS_start().
 */
Void Timer_startup()
{
    Int i;
    Timer_Object *obj;

    if (Timer_startupNeeded) {
        for (i = 0; i < Timer_numTimerDevices; i++) {
            obj = Timer_module->handles[i];
            /* if timer was statically created/constructed */
            if ((obj != NULL) && (obj->staticInst)) {
                if (obj->startMode == Timer_StartMode_AUTO) {
                        Timer_start(obj);
                }
            }
        }
    }
}

/*
 *  ======== Timer_getHandle ========
 */
Timer_Handle Timer_getHandle(UInt id)
{
    Assert_isTrue((id < Timer_numTimerDevices), NULL);
    return (Timer_module->handles[id]);
}

/*
 *  ======== Timer_Instance_init ========
 * 1. Select timer based on id
 * 2. Mark timer as in use
 * 3. Init timer obj using params
 * 4. Create Hwi if tickFxn != NULL
 * 5. Initialize timer
 * 6. Configure timer (wrt emulation, frequency, etc.)
 * 7. Set period
 * 8. Timer_start()
 *
 */
Int Timer_Instance_init(Timer_Object *obj, Int id, Timer_FuncPtr tickFxn, const Timer_Params *params, Error_Block *eb)
{
    Int status;
    UInt key;
    Int i;
    Hwi_Params hwiParams;
    UInt tempId = 0xffff;

    if (id >= Timer_numTimerDevices) {
        if (id != Timer_ANY) {
            Error_raise(eb, Timer_E_invalidTimer, id, 0);
            return (BAD_TIMER_ID);
        }
    }

    key = Hwi_disable();

    if (id == Timer_ANY) {
        for (i = 0; i < Timer_numTimerDevices; i++) {
            if ((Timer_anyMask & (1 << i))
                && (Timer_module->availMask & (1 << i))) {
                Timer_module->availMask &= ~(1 << i);
                tempId = i;
                break;
            }
        }
    }
    else if (Timer_module->availMask & (1 << id)) {
        Timer_module->availMask &= ~(1 << id);
        tempId = id;
    }

    Hwi_restore(key);

    obj->staticInst = FALSE;

    if (tempId == 0xffff) {
        Error_raise(eb, Timer_E_notAvailable, id, 0);
        return (NO_TIMER_AVAIL);
    }
    else {
        obj->id = tempId;
    }

    if (params->clockSource == Timer_Source_ACLK) {
        obj->controlRegInit = 0x0100 | params->inputDivider;
    }
    else if (params->clockSource == Timer_Source_SMCLK) {
        obj->controlRegInit = 0x0200 | params->inputDivider;
    }
    else if (params->clockSource == Timer_Source_EXTERNAL) {
        obj->controlRegInit = 0x0000 | params->inputDivider;
    }
    else if (params->clockSource == Timer_Source_EXTERNAL_INVERTED) {
        obj->controlRegInit = 0x0300 | params->inputDivider;
    }
    else {
        return (NO_HWI_OBJ);
    }

    obj->runMode = params->runMode;
    obj->startMode = params->startMode;
    obj->period = params->period;
    obj->periodType = params->periodType;
    obj->arg = params->arg;
    obj->intNum = Timer_module->device[obj->id].intNum;
    obj->tickFxn = tickFxn;
    obj->prevThreshold = 0;
    obj->savedCurrCount = 0;
    obj->rollovers = 0;
    obj->synchronous = params->synchronous;

    if (params->extFreq.lo == 0) {
        if (params->clockSource == Timer_Source_ACLK) {
            obj->frequency.lo = ClockFreqs_ACLK;
        }
        else if (params->clockSource == Timer_Source_SMCLK) {
            obj->frequency.lo = ClockFreqs_SMCLK;
        }
    }
    else {
        obj->frequency.lo = params->extFreq.lo;
    }
    obj->frequency.hi = params->extFreq.hi;

    obj->inputDivider = params->inputDivider;
    obj->inputDividerExp = params->inputDividerExp;

    if (obj->tickFxn) {
        if (params->hwiParams) {
            Hwi_Params_copy(&hwiParams, (params->hwiParams));
        }
        else {
            Hwi_Params_init(&hwiParams);
        }

        hwiParams.arg = (UArg)obj->id;

        if (obj->runMode == Timer_RunMode_CONTINUOUS) {
            if (params->nesting == TRUE) {
                obj->hwi = Hwi_create(obj->intNum, Timer_periodicNestStub,
                    &hwiParams, eb);
            }
            else {
                obj->hwi = Hwi_create(obj->intNum, Timer_periodicStub,
                    &hwiParams, eb);
            }
        }
        else {
            if (params->nesting == TRUE) {
                obj->hwi = Hwi_create(obj->intNum, Timer_oneShotNestStub,
                    &hwiParams, eb);
            }
            else {
                obj->hwi = Hwi_create(obj->intNum, Timer_oneShotStub,
                    &hwiParams, eb);
            }
        }

        if (obj->hwi == NULL) {
            return (NO_HWI_OBJ);
        }
    }
    else {
        obj->hwi = NULL;
    }

    Timer_module->handles[obj->id] = obj;

    Timer_initDevice(obj);

    if (obj->periodType == Timer_PeriodType_MICROSECS) {
        if (!Timer_setPeriodMicroSecs(obj, obj->period)) {
            Error_raise(eb, Timer_E_cannotSupport, obj->period, 0);
            Hwi_restore(key);
            return (BAD_PERIOD);
        }
    }

    status = Timer_postInit(obj, eb);

    if (status) {
        return (status);
    }

    if (obj->startMode == Timer_StartMode_AUTO) {
        Timer_start(obj);
    }

    return (0);
}

/*
 *  ======== Timer_reconfig ========
 *
 * 1. Init obj using params
 * 2. Timer_init()
 * 3. Configure timer (wrt emulation, frequency, etc.)
 * 4. Set period
 * 5. Timer_start()
 *
 */
Void Timer_reconfig (Timer_Object *obj, Timer_FuncPtr tickFxn, const
    Timer_Params *params, Error_Block *eb)
{
    obj->controlRegInit = params->controlRegInit | params->inputDivider;
    obj->runMode = params->runMode;
    obj->startMode = params->startMode;
    obj->periodType = params->periodType;
    obj->prevThreshold = params->prevThreshold;
    obj->rollovers = 0;
    obj->savedCurrCount = 0;
    obj->synchronous = params->synchronous;
    obj->inputDividerExp = params->inputDividerExp;
    if (obj->periodType == Timer_PeriodType_MICROSECS) {
        if (!Timer_setPeriodMicroSecs(obj, params->period)) {
            Error_raise(eb, Timer_E_cannotSupport, params->period, 0);
        }
    }
    else {
        obj->period = params->period;
    }

    obj->arg = params->arg;
    obj->tickFxn = tickFxn;

    if (params->extFreq.lo) {                   /* (extFreq.hi is ignored) */
        obj->frequency.lo = params->extFreq.lo;
    }

    Timer_postInit(obj, eb);

    if (obj->startMode == Timer_StartMode_AUTO) {
        Timer_start(obj);
    }
}

/*
 *  ======== Timer_Instance_finalize ========
 */
Void Timer_Instance_finalize(Timer_Object *obj, Int status)
{
    UInt key;

    /* note: fall through in switch below is intentional */
    switch (status) {
        /* Timer_delete() */
        case TIMER_DELETED:

        /* setPeriodMicroSecs failed */
        case BAD_PERIOD:
            Timer_initDevice(obj);
            if (obj->hwi) {
                Hwi_delete(&obj->hwi);
            }

        /* Hwi create failed */
        case NO_HWI_OBJ:

        /* timer not available */
        case NO_TIMER_AVAIL:

        /* invalid timer id */
        case BAD_TIMER_ID:

        default:
            break;
    }

    key = Hwi_disable();
    Timer_module->availMask |= (0x1 << obj->id);
    Timer_module->handles[obj->id] = NULL;
    Hwi_restore(key);
}

/*
 *  ======== Timer_start ========
 *
 * 1. Hwi_disable()
 * 2. Clear the counter
 * 3. Clear timer interrupt flag
 * 4. Set next compare threshold (per configured period)
 * 5. Enable timer interrupt
 * 6. Start timer
 * 7. Hwi_restore()
 *
 */
Void Timer_start(Timer_Object *obj)
{
    ti_catalog_msp432_peripherals_timers_TimerRegs *timer;
    UInt key;

    timer = (ti_catalog_msp432_peripherals_timers_TimerRegs *)
        Timer_module->device[obj->id].baseAddr;

    key = Hwi_disable();

    /* reset timer counts */
    timer->control |= TIMER_CONTROL_CLEAR;

    /* clear timer interrupt flag */
    timer->cctl_0 &= ~TIMER_COMPARE_INTR_PENDING;

    /* zero previous threshold */
    obj->prevThreshold = 0;

    /* set compare threshold for next interrupt */
    timer->cc_compare_0 = obj->period;

    /* enable capture/compare 0 interrupts */
    timer->cctl_0 |= TIMER_COMPARE_INTR_ENABLE;

    /* start timer */
    timer->control |= TIMER_CONTROL_START;

    Hwi_restore(key);
}

/*
 *  ======== Timer_stop ========
 *
 * 1. Stop timer
 * 2. Disable timer interrupt
 *
 */
Void Timer_stop(Timer_Object *obj)
{
    ti_catalog_msp432_peripherals_timers_TimerRegs *timer;

    timer = (ti_catalog_msp432_peripherals_timers_TimerRegs *)
        Timer_module->device[obj->id].baseAddr;

    /* stop timer */
    timer->control = obj->controlRegInit | obj->inputDivider;

    /* disable capture/compare 0 interrupts */
    timer->cctl_0 &= ~TIMER_COMPARE_INTR_ENABLE;

    /* clear timer interrupt flag */
    timer->cctl_0 &= ~TIMER_COMPARE_INTR_PENDING;
}

/*
 *  ======== Timer_setPeriod ========
 *
 * 1. Stop timer
 * 2. Set period value in timer obj
 *
 */
Void Timer_setPeriod(Timer_Object *obj, UInt32 period)
{
    Timer_stop(obj);
    obj->period = period;
}

/*
 *  ======== Timer_setPeriodMicroSecs ========
 *
 * 1. Stop timer
 * 2. Compute counts
 * 3. Set new period value in timer obj
 *
 */
Bool Timer_setPeriodMicroSecs(Timer_Object *obj, UInt32 period)
{
    Types_FreqHz freqHz;
    UInt32 counts;
    UInt32 freqKHz;

    Timer_stop(obj);

    Timer_getFreq(obj, &freqHz);
    freqKHz = freqHz.lo / 1000;

    if (Timer_checkOverflow(freqKHz, period/1000)) {
        return (FALSE);
    }
    else {
        counts = (freqKHz * period) / 1000;
        obj->period = counts;
        obj->periodType = Timer_PeriodType_COUNTS;
        return(TRUE);
    }
}

/*
 *  ======== Timer_trigger ========
 *
 *  1. stop timer
 *  2. write the period with insts
 *  3. start the timer.
 *
 */
Void Timer_trigger(Timer_Object *obj, UInt32 insts)
{
    UInt key;

    /* follow proper procedure for dynamic period change */
    key = Hwi_disable();

    /* Force SMCLK for sweep timer */
    obj->controlRegInit &= ~0x0100;     /* clear ACLK bit */
    obj->controlRegInit |= 0x0200;      /* enable SMCLK */

    Timer_stop(obj);

    Timer_setPeriod(obj, insts);
    Timer_start(obj);
    Hwi_restore(key);
}

/*
 *  ======== Timer_getPeriod ========
 */
UInt32 Timer_getPeriod(Timer_Object *obj)
{
    return(obj->period);
}

/*
 *  ======== Timer_getCount ========
 */
UInt32 Timer_getCount(Timer_Object *obj)
{
    ti_catalog_msp432_peripherals_timers_TimerRegs *timer;
    UInt first;
    UInt second;

    timer = (ti_catalog_msp432_peripherals_timers_TimerRegs *)
        Timer_module->device[obj->id].baseAddr;

    /* if timer's source clock is synchronous to CPU: only read counts once */
    if (obj->synchronous) {
        first = timer->count;
    }

    /* else, must do multiple reads to avoid possible spurious values */
    else {
        /* read twice, expecting equal values, or within read latency */
        do {
            first = timer->count;
            second = timer->count;
        } while ((first != second) && ((second - first) > READ_LATENCY));
    }

    return (((UInt32) first) & 0xffff);
}

/*
 *  ======== Timer_oneShotStub ========
 */
Void Timer_oneShotStub(UArg arg)
{
    Timer_Object *obj;
    obj = Timer_module->handles[(UInt)arg];

    /* stop the timer (and disable this interrupt source) */
    Timer_stop(obj);

    /* call the tick function */
    obj->tickFxn(obj->arg);
}

/*
 *  ======== Timer_oneShotNestStub ========
 */
Void Timer_oneShotNestStub(UArg arg)
{
    Timer_Object *obj;
    obj = Timer_module->handles[(UInt)arg];

    /* stop the timer (and disable this interrupt source) */
    Timer_stop(obj);

    /* enable interrupts to allow nesting */
    Hwi_enable();

    /* call the tick function */
    obj->tickFxn(obj->arg);

    /* disable interrupts as unwind the ISR */
    Hwi_disable();
}

/*
 *  ======== Timer_periodicStub ========
 */
Void Timer_periodicStub(UArg arg)
{
    Timer_Object *obj;
    ti_catalog_msp432_peripherals_timers_TimerRegs *timer;

    obj = Timer_module->handles[(UInt)arg];

    timer = (ti_catalog_msp432_peripherals_timers_TimerRegs *)
        Timer_module->device[obj->id].baseAddr;

    /* clear timer interrupt flag */
    timer->cctl_0 &= ~TIMER_COMPARE_INTR_PENDING;

    /* for DYNAMIC, mode latch prevThreshold and detect rollovers */
    if (obj->runMode == Timer_RunMode_DYNAMIC) {
        /*
         * If the current threshold is less than the prevThreshold
         * then a rollover has occurred.
         *
         * If the current threshold is equal to prevThreshold then the timer
         * count wrapped around and generated a new interrupt; increment
         * the rollover count to resume ticking.
         */
        if (obj->prevThreshold >= timer->cc_compare_0) {
            obj->rollovers += 1;
        }

        /* save previous threshold value */
        obj->prevThreshold = timer->cc_compare_0;
    }
    else {
        /* save previous threshold value */
        obj->prevThreshold = timer->cc_compare_0;
        obj->savedCurrCount = timer->cc_compare_0;

        /* set next interrupt threshold; interrupt now if set too late */
        Timer_setNextTick(obj, 1);
    }

    /* call the tick function */
    obj->tickFxn(obj->arg);
}

/*
 *  ======== Timer_periodicNestStub ========
 */
Void Timer_periodicNestStub(UArg arg)
{
    Timer_Object *obj;
    ti_catalog_msp432_peripherals_timers_TimerRegs *timer;

    obj = Timer_module->handles[(UInt)arg];

    timer = (ti_catalog_msp432_peripherals_timers_TimerRegs *)
        Timer_module->device[obj->id].baseAddr;

    /* clear timer interrupt flag */
    timer->cctl_0 &= ~TIMER_COMPARE_INTR_PENDING;

    /* for DYNAMIC, mode latch prevThreshold and detect rollovers */
    if (obj->runMode == Timer_RunMode_DYNAMIC) {
        /*
         * if the current threshold is less than the prevThreshold
         * then a rollover has occurred.
         */
        if (obj->prevThreshold > timer->cc_compare_0) {
            obj->rollovers += 1;
        }

        /* save previous threshold value */
        obj->prevThreshold = timer->cc_compare_0;
    }
    else {
        /* save previous threshold value */
        obj->prevThreshold = timer->cc_compare_0;
        obj->savedCurrCount = timer->cc_compare_0;

        /* set next interrupt threshold; interrupt now if set too late */
        Timer_setNextTick(obj, 1);
    }

    /* allow nesting of other interrupts ... */
    timer->cctl_0 &= ~TIMER_COMPARE_INTR_ENABLE;
    Hwi_enable();

    /* call the tick function */
    obj->tickFxn(obj->arg);

    /* disable interrupts as unwind the ISR */
    Hwi_disable();
    timer->cctl_0 |= TIMER_COMPARE_INTR_ENABLE;
}

/*
 *  ======== Timer_getExpiredCounts ========
 *
 *  This API is used by the TimestampProvider as part of retrieving a timestamp
 *  using a timer and a tick counter. It returns the expired counts since the
 *  last serviced timer interrupt.
 *
 *  This API must be called with interrupts disabled; the TimestampProvider
 *  must disable interrupts while retrieving the tick count and calling this
 *  API.
 *
 *  The TimestampProvider uses a 32-bit timer and 32-bit tick count to track
 *  the timestamp. The tick count either comes from the Clock module or is
 *  stored in the TimestampProvider's module state and incremented by an ISR
 *  when the timer expires.
 *
 *  For MSP432 we have 16-bit timers, and use a timer compare feature to
 *  trigger an interrupt upon a specific threshold count being reached.  The
 *  timer counts can rollover (going thru zero), on the way to reaching the
 *  next threshold.  We need to  accommodate this rollover as part of
 *  determining expired counts.
 *
 *  We also need to handle the case where there is a large period value used
 *  for the timer, and the timer is ticking at a fast rate (e.g., the CPU
 *  rate, via an SMCLK selection).  For this case, it is possible that
 *  interrupts are disabled before the timer reaches threshold, and then the
 *  timer reaches the threshold count and asserts an interrupt, and then
 *  continues to count upwards before it is read in this routine.  If the
 *  timer rolled past zero, then we need to know that there is an interrupt
 *  pending, otherwise we'd report a low count, versus the period plus
 *  that low count.
 *
 *  To be sure to catch the interrupt, we sample the interrupt flag, read
 *  the count, and then sample the interrupt flag again:
 *
 *      intrFlag1
 *      count
 *      intrFlag2
 *
 *  If intrFlag1 is set, then we know we've reached the period count, and
 *  need to add it to the reported counts.  If intrFlag2 is set, but
 *  intrFlag1 wasn't, we know the timer just reached threshold, and simply
 *  report the period count.
 *
 *  If neither interrupt flag is set, we can then compute the expired counts by
 *  comparing the count to the previous interrupt threshold (saved in the
 *  timer object).  If the current count is greater than or equal to the
 *  previous threshold value, then we know there has been no counter rollover,
 *  and the expired counts is simply:
 *
 *      result = count - prevThresh
 *
 *  If the current count is less than the previous threshold, then we know a
 *  counter rollover has occurred since the last ISR.  In this case, the
 *  expired counts has to include those between the previous threshold and
 *  zero, plus any counts after rolling past zero:
 *
 *      result = (0 - prevTresh) + count
 *
 *  Similar logic to compare the current count to previous threshold can
 *  be used for the case where we know intrFlag1 has been set, and we
 *  need to figure the counts to be added to the period counts.
 *
 */
UInt32 Timer_getExpiredCounts(Timer_Object *obj)
{
    ti_catalog_msp432_peripherals_timers_TimerRegs *timer;
    UInt32 result32;
    UInt32 count32;
    UInt32 thresh32;
    UInt32 period32;
    UInt32 prev32;
    Bool intrFlag1;
    Bool intrFlag2;

    timer = (ti_catalog_msp432_peripherals_timers_TimerRegs *)
        Timer_module->device[obj->id].baseAddr;

    intrFlag1 = timer->cctl_0 & TIMER_COMPARE_INTR_PENDING;
    count32 = Timer_getCount(obj) & 0xffff;
    intrFlag2 = timer->cctl_0 & TIMER_COMPARE_INTR_PENDING;
    prev32 = obj->prevThreshold & 0xffff;

    /* interrupt pending before read count? */
    if (intrFlag1) {
        thresh32 = timer->cc_compare_0 & 0xffff;  /* threshold for interrupt */
        period32 = Timer_getPeriod(obj) & 0xffff; /* period count */

        /* threshold reached; no wrap thru zero yet */
        if (count32 >= thresh32) {
            result32 = (count32 - thresh32) + period32;
        }
        /* threshold reached; count has wrapped thru zero */
        else {
            result32 = (0x10000 - thresh32) + count32 + period32;
        }
    }

    /* new interrupt now pending, when wasn't before read the count */
    else if (intrFlag2) {
        result32 = Timer_getPeriod(obj) & 0xffff; /* return period count */
    }

    /* interrupt threshold not reached; check if wrapped thru zero */
    else if (count32 >= prev32) {
        result32 = count32 - prev32;
    }

    /* interrupt threshold not reached; count has wrapped thru zero */
    else {
        result32 = (0x10000 - prev32) + count32;
    }

    return (result32);
}

/*
 *  ======== Timer_getExpiredTicks ========
 */
UInt32 Timer_getExpiredTicks(Timer_Object *obj, UInt32 tickPeriod)
{
    UInt32 ticks;

    ticks = Timer_getExpiredCounts(obj) / tickPeriod;

    return (ticks);
}

/*
 *  ======== Timer_getCurrentTick ========
 *  Uses 48 bits of precision.
 *  at 32.768 KHz, that's 8,589,934,592 seconds,
 *  or 272 years before tick would be miscalculated
 */
UInt32 Timer_getCurrentTick(Timer_Object *obj, Bool saveFlag)
{
    UInt32 rollovers;
    UInt currCount;
    UInt32 tick;
    UInt32 s1;
    UInt r;

    currCount = Timer_getCount(obj);

    rollovers = obj->rollovers;

    if (currCount < obj->prevThreshold) {
        rollovers += 1;
    }

    s1 = rollovers / obj->period;                    /* upper 32 of 48 bits */
    r = rollovers - s1 * obj->period;        /* remainder of upper division */
    tick = (((UInt32)r << 16) + currCount) / obj->period;  /* lower 16-bits */
    tick = ((UInt32)(s1 & 0xFFFF) << 16) + (tick & 0xFFFF);

    /* save for later use by Timer_setNextTick() */
    if (saveFlag != 0) {
        obj->savedCurrCount = tick * obj->period;
    }

    return (tick);
}

/*
 *  ======== Timer_getFreq ========
 */
Void Timer_getFreq(Timer_Object *obj, Types_FreqHz *freq)
{
    UInt divider;

    switch(obj->controlRegInit & ID_MASK) {
        case Timer_ID_1:
            divider = 1;
            break;

        case Timer_ID_2:
            divider = 2;
            break;

        case Timer_ID_4:
            divider = 4;
            break;

        default:
            divider = 8;
            break;
    }

    divider *= (obj->inputDividerExp + 1);

    freq->lo = obj->frequency.lo / divider;
    freq->hi = 0;
}

/*
 *  ======== Timer_getFunc ========
 */
Timer_FuncPtr Timer_getFunc(Timer_Object *obj, UArg *arg)
{
    *arg = obj->arg;
    return (obj->tickFxn);
}

/*
 *  ======== Timer_setFunc ========
 */
Void Timer_setFunc(Timer_Object *obj, Timer_FuncPtr fxn, UArg arg)
{
    obj->tickFxn = fxn;
    obj->arg = arg;
}

/*
 *  ======== Timer_checkOverflow ========
 */
Bool Timer_checkOverflow(UInt32 a, UInt32 b)
{
    return ((b > 0) && (a > Timer_MAX_PERIOD/b));
}

/* ======== Timer_initDevice ========
 *
 * 1. Stop timer (set control registers back to default value)
 * 2. Disable timer interrupt
 * 3. Clear any pending interrupt
 * 4. Clear counters
 *
 */
Void Timer_initDevice(Timer_Object *obj)
{
    ti_catalog_msp432_peripherals_timers_TimerRegs *timer;
    UInt key;

    timer = (ti_catalog_msp432_peripherals_timers_TimerRegs *)
        Timer_module->device[obj->id].baseAddr;

    key = Hwi_disable();

    /* stop timer; set default control register */
    timer->control = MC | obj->controlRegInit;
    timer->expansion = obj->inputDividerExp;

    /* clear timer interrupt flag */
    timer->cctl_0 &= ~TIMER_COMPARE_INTR_PENDING;

    /* reset timer counts */
    timer->control |= TIMER_CONTROL_CLEAR;

    /* freeze the timer when the CPU is halted */
    REG(SYS_PERI_HALTCTL_REG) |= 1 << obj->id;

    Hwi_restore(key);
}

/*
 *  ======== Timer_postInit ========
 */
Int Timer_postInit (Timer_Object *obj, Error_Block *eb)
{
    UInt key;

    key = Hwi_disable();

    Timer_initDevice(obj);

    Timer_setPeriod(obj, obj->period);

    Hwi_restore(key);

    return (0);
}

And if you think this might be worth pursuing, I'd really like a pointer on how to rebuild the stuff to make this work.

Thanks,

Rob

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
 Share
Followers 0
Go to topic listing
×
×
  • Create New...