Notes

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* MSP432 CODE EXAMPLE DISCLAIMER
*
* MSP432 code examples are self-contained low-level programs that typically
* demonstrate a single peripheral function or device feature in a highly
* concise manner. For this the code may rely on the device's power-on default
* register values and settings such as the clock configuration and care must
* be taken when combining code from several examples to avoid potential side
* effects. Also see http://www.ti.com/tool/mspdriverlib for an API functional
* library & https://dev.ti.com/pinmux/ for a GUI approach to peripheral configuration.
*
* --/COPYRIGHT--*/
//***************************************************************************************
// MSP432P401 Demo - Timer0_A3 Capture of ACLK
//
// Description; Capture a number of periods of the ACLK clock and store them in an array.
// When the set number of periods is captured the program is trapped and the LED on
// P1.0 is toggled. At this point halt the program execution read out the values using
// the debugger.
//
// Ensure to connect ACLK out (P4.2) to TA0.CCI2A (P2.5) with a jumper.
//
// ACLK = REFOCLK = 32kHz, MCLK = SMCLK = default DCODIV = 3MHz.
//
// MSP432P401
// -----------------
// /|| |
// | | P2.5|<-- TA0.CCI2A
// --|RST | |
// | P4.2|--> ACLK
// | |
// | P1.0|-->LED
//
//
// William Goh
// Texas Instruments Inc.
// June 2016 (updated) | June 2014 (created)
// Built with CCSv6.1, IAR, Keil, GCC
//***************************************************************************************
#include "msp.h"
#include <stdint.h>
#include <Lab4_Part2.h>
int count = 0;
int result = 0;
int sec0 = 0;
int init = 0;
int diff = 0;

volatile int sec1 = 0;
volatile int sec2 = 0;
volatile int sec3 = 0;
volatile int sec4 = 0;


int main(void)
{
WDT_A->CTL = WDT_A_CTL_PW | WDT_A_CTL_HOLD; // Stop watchdog timer

P4->DIR = ALLOUTPINS; //configure all output pins

// Configure GPIO
P2->DIR = 0x00; //2.4 as input
P2->SEL0 = BIT4; // SEL0 = 1
P2->SEL1 = 0x00; // SEL1 = 0

P2->DIR = 0x00; // 2.5 as input
P2->SEL0 = BIT5; // SEL0 = 1
P2->SEL1 = 0x00; // SEL1 = 0


TIMER_A0->CCTL[1] = TIMER_A_CCTLN_CM_1 | // Capture rising edge,
TIMER_A_CCTLN_CCIS_0 | // Use CCI1A=ACLK,
TIMER_A_CCTLN_CCIE | // Enable capture interrupt
TIMER_A_CCTLN_CAP | // Enable capture mode,
TIMER_A_CCTLN_SCS; // Synchronous capture

TIMER_A0->CCTL[2] = TIMER_A_CCTLN_CM_1 | // Capture rising edge,
TIMER_A_CCTLN_CCIS_0 | // Use CCI2A=ACLK,
TIMER_A_CCTLN_CCIE | // Enable capture interrupt
TIMER_A_CCTLN_CAP | // Enable capture mode,
TIMER_A_CCTLN_SCS; // Synchronous capture

TIMER_A0->CTL |= TIMER_A_CTL_TASSEL_1 | // Use ACLK as clock source,
TIMER_A_CTL_MC_2 | // Start timer in continuous mode
TIMER_A_CTL_CLR | // clear TA0R
TIMER_A_CTL_ID_3;

TIMER_A0->CCTL[1] &= ~(TIMER_A_CCTLN_CCIFG);
TIMER_A0->CCTL[2] &= ~(TIMER_A_CCTLN_CCIFG);

NVIC_EnableIRQ(TA0_N_IRQn); //Enable timer0 interrupt
__enable_irq(); // Enable global interrupt

while(1)
{

INIT_LCD(); //initializes the LCD
CLEAR_LCD(); //clears anything on the LCD
sec0 = 8 * result / 320;
sec1 = (sec0 / 100) % 10;

sec2 = (sec0 / 10) % 10;
sec3 = sec0 % 10;
if(sec1 >= 9)
{
sec4 = 0x31;
sec1 = 0;

} //endif
else
sec4 = 0x30;

OUTPUT_CHAR(sec4);
OUTPUT_CHAR(0x30 + sec1);
OUTPUT_CHAR('.'); //displays character .
OUTPUT_CHAR(0x30 + sec2);
OUTPUT_CHAR(0x30 + sec3);
}


} // end main

// Timer A0 interrupt service routine
void TA0_N_IRQHandler(void)
{
count++;
if (count == 1)
{
TA0CTL |= TACLR;
TIMER_A0->CCTL[1] &= ~(TIMER_A_CCTLN_CCIFG);
//sec4=0;

}
if (count == 2)
{
result = TA0CCR2;
count = 0;
TIMER_A0->CCTL[2] &= ~(TIMER_A_CCTLN_CCIFG);

}

}