#include "timer_a1.h"

#include "inc/msp432p401r.h"

void (*timer_a1_task)(void); // user function

// Activate Timer A1 interrupts to run user task periodically
// 16 bits period in units (24/SMCLK, with SMCLK 12 MHz -> 2us)
void TimerA1Init(void (*task)(void), uint16_t period) {
    timer_a1_task = task;

    // bits9-8=10, clock source to SMCLK
    // bits7-6=10, input clock divider
    // bits5-4=00, stop mode
    // bit2=0, set this bit to clear
    // bit1=0, no interrupt on
    TIMER_A1->CTL = 0x0280;

    // bits15-14=00, no capture mode
    // bit8=0, compare mode
    // bit4=1, enable capture/compare interrupt on CCIFG
    // bit2=0, output this value in output mode 0
    TIMER_A1->CCTL[0] &= ~0x0001;

    TIMER_A1->CCR[0] = (period - 1);
    TIMER_A1->EX0 = 0x0005;
    NVIC->IP[3] = (NVIC->IP[3]&0xFFFFFF00)|0x00000040; // priority 2
    NVIC->ISER[0] = 0x00001000; // enable interrupt 12 in NVIC
    TIMER_A1->CTL |= 0x0014; // reset and start Timer A in up mode
    TIMER_A1->CTL |= 0x0020; // Enable Timer A1 interrupts (TAIE)
}

void TA1_0_IRQHandler(void) {
    TIMER_A1->CCTL[0] &= ~0x0001;
    timer_a1_task();
}