#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;

    // Stop timer, SMCLK, /4 divider
    TIMER_A1->CTL = 0x0280;

    // Configure CCR0
    TIMER_A1->CCTL[0] = 0x0010; // Compare mode, enable interrupt
    TIMER_A1->CCR[0] = (period - 1);
    
    // Clock divider (EX0 register)
    TIMER_A1->EX0 = 0x0005; // /6 divider (additional to the /4 above)
    
    // NVIC configuration
    NVIC->IP[3] = (NVIC->IP[3]&0xFFFFFF00)|0x00000040; // priority 2
    NVIC->ISER[0] = 0x00001000; // enable interrupt 12 in NVIC
    
    // Enable timer interrupts and start in up mode
    TIMER_A1->CTL |= 0x0014 | 0x0020; // reset, up mode, enable interrupts
    
    NVIC_EnableIRQ(TA1_0_IRQn);
}

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