/* EdgeTriggered.c
 * Jonathan Valvano
 * July 19, 2025
 * Derived
 * Derived from gpio_toggle_output_LP_MSPM0G3507_nortos_ticlang
 *              gpio_input_capture_LP_MSPM0G3507_nortos_ticlang
 * Will invoke LaunchPad_Init
 */

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#include <ti/devices/msp/msp.h>
#include "../inc/EdgeTriggered.h"
#include "../inc/LaunchPad.h"

// PB21 is S3 negative logic switch,  index 48 in IOMUX PINCM table

// Arm interrupts on fall of PB21
// interrupts will be enabled in main after all initialization
void EdgeTriggered_Init(void){
  LaunchPad_Init(); // PB21 is input with internal pull up resistor
  GPIOB->POLARITY31_16 = 0x00000800;     // falling
  GPIOB->CPU_INT.ICLR = 0x00200000;   // clear bit 21
  GPIOB->CPU_INT.IMASK = 0x00200000;  // arm PB21
  NVIC->IP[0] = (NVIC->IP[0]&(~0x0000FF00))|2<<14;    // set priority (bits 15,14) IRQ 1
  NVIC->ISER[0] = 1 << 1; // Group1 interrupt
}