MSPM0G3507: Simple Timer example

Here's something I use. It doesn't do exactly what you're asking, but it illustrates some of the mechanics.

You need to provide the value of "HZ" (clk.h), which is just the system clock speed. If you haven't fooled with the clock then "#define HZ 32000000UL // 32MHz" will suffice.

///
//      timer.c
//      Simple timer for pausing in WFI.
//      No Warranty, No Support. I may not even exist.
//
#include <ti/devices/msp/msp.h>
#include "clk.h"        // HZ
#include "timer.h"
#define TIMT        TIMG8
#define TIMT_ISR    TIMG8_IRQHandler
#define TIMT_IRQn   TIMG8_INT_IRQn
volatile uint32_t timer_ms;

void
TIMT_ISR(void)
{
    uint32_t mis;
    mis = TIMT->CPU_INT.MIS;                // Enabled interrupts
    TIMT->CPU_INT.ICLR = mis;               // Clear 'em all
    if (mis & GPTIMER_CPU_INT_MIS_Z_SET)
    {
        ++timer_ms;
    }
    return;
}

void
timer_init(void)
{
    //  Power up timer
    TIMT->GPRCM.PWREN = (GPTIMER_PWREN_KEY_UNLOCK_W | GPTIMER_PWREN_ENABLE_ENABLE);

    //  CTR: Start at 0, repeat, count up, Advance per CCCTL_01[0].ACOND
    TIMT->COUNTERREGS.CTRCTL = GPTIMER_CTRCTL_CAC_CCCTL0_ACOND|GPTIMER_CTRCTL_CVAE_ZEROVAL|
                                GPTIMER_CTRCTL_REPEAT_REPEAT_1|GPTIMER_CTRCTL_CM_UP;

    //  1kHz from BUSCLK (SYSCLK)
    TIMT->COUNTERREGS.LOAD = (HZ/1000)-1;     // 1kHz period

    //  CCR0: advance on clock
    TIMT->COUNTERREGS.CCCTL_01[0] = GPTIMER_CCCTL_01_ACOND_TIMCLK;

    //  Enable clock, then timer
    TIMT->CLKSEL = GPTIMER_CLKSEL_BUSCLK_SEL_ENABLE;
    TIMT->COMMONREGS.CCLKCTL = GPTIMER_CCLKCTL_CLKEN_ENABLED;
    TIMT->COUNTERREGS.CTRCTL |= GPTIMER_CTRCTL_EN_ENABLED;

    TIMT->CPU_INT.IMASK |= GPTIMER_CPU_INT_IMASK_Z_SET; // Interrupt on counter wrap
    NVIC_ClearPendingIRQ(TIMT_IRQn);
    NVIC_EnableIRQ(TIMT_IRQn);
    return;
}

void
timer_wait(uint32_t ms)
{
    uint32_t start = timer_ms;

    while (timer_ms - start < ms)
    {
        __WFI();
    }
    return;
}