lpc1114/IR.c at master · zinahe/lpc1114 · GitHub

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#include "LPC1114.h"
#include "GPIO.h"
#include "SysTick.h"
#include "UART.h"

#define GPIO1_5			5

#define IR_STATE_ON		1
#define IR_STATE_OFF	2

volatile uint32_t IR_timer;
volatile uint32_t IR_code;
volatile uint32_t IR_state;
volatile uint32_t IR_bit_count;

void IR_Timer_callback(uint32_t state) {

	if (IR_state == IR_STATE_ON) {

		IR_timer++;
	} else {

		// IR pin Logical Low (Watch for operator precedence b/n & and ==)
		if ((GPIO1DATA & (1 << GPIO1_5)) == 0)  {
			IR_timer++;
		}
	}

}


void main() {

	// Initialize SysTick, GPIO and UART
	GPIO_init();
	SysTick_init();
	UART_init();

	// ------------- GPIO Interrupt Configuration ------------------
	// GPIO1_ISENSE defaults to Edge Sensitive trigger

	// GPIO1_IEDGES defaults to GPIO1_IEVENT control
	// Configure both edges trigger
	GPIO1_IEDGES = (1 << GPIO1_5);

	// Enable Rising Edge trigger
	//GPIO1_IEVENT = (1 << GPIO1_5);

	// Enable GPIO Interrupt
	GPIO1_IENABLE = (1 << GPIO1_5);

	// Enable GPIO1 Interrupt in NVIC
	NVIC_SETENA = (1 << NVIC_GPIO1_BIT);
	// ------------- GPIO Interrupt Configuration ------------------

	// Initilize IR state
	IR_timer = 0;
	IR_bit_count = 0;
	IR_code = 0;
	IR_state = IR_STATE_OFF;

	// Create and setup IR timer
	Timer_t IR_timer = { 1, 0, 0, 0, IR_Timer_callback };
	SysTick_run(&IR_timer);

	// Despatch timer callbacks if available; or just wait
	while(1) {
		if (Callback_counter > 0) {
			(Timer_callbacks[--Callback_counter])(0);
		}
	}

}

void GPIO1_Handler(void) {

	// GPIO1_IMASKSTAT can be used to identify which pin is causing the interrupt

	// Clear GPIO Edge Trigger Intrrupt Signal
	GPIO1_ICLR = (1 << GPIO1_5);

	if (GPIO1DATA & (1 << GPIO1_5)) {

		// Rising edge trigger

		if (IR_state == IR_STATE_OFF) {

			// Check for the first 9ms pulse train during OFF state (Watch the difference beween bitwise & and logical &&)
			if ((IR_timer >= 35) && (IR_timer <= 38)) {

				// Enter ON state
				IR_state = IR_STATE_ON;

			}
		}

	} else {

		// Falling edge trigger

		if (IR_state == IR_STATE_ON) {

			// 2.25ms pulse width = IR Bit 1
			if ((IR_timer >= 8) && (IR_timer <= 10)) {
				IR_code++;
				IR_bit_count++;

				if (IR_bit_count < 32)
					IR_code = (IR_code << 1);
			}

			// 1.12ms pulse width = IR Bit 0
			if ((IR_timer >= 3) && (IR_timer <= 6)) {
				IR_bit_count++;

				if (IR_bit_count < 32)
					IR_code = (IR_code << 1);
			}

			// 32 IR bits = Complete IR command
			if (IR_bit_count == 32) {

				// Payload
				UART_write(&IR_code, 4);


				if (IR_code == 0x00FDB04F) {
					GPIO1DATA ^= (1 << PIO1_9);
				}


				// Exit to OFF state
				IR_state = IR_STATE_OFF;
				IR_code = 0;
				IR_bit_count = 0;

			}
		}

		// Reset timer on all falling edge triggers
		IR_timer = 0;
	}
}

/* IR Buttons/Commands

ON/OFF		0x00FD00FF
PLAY/PAUSE	0x00FDA05F
>>			0x00FD609F
<< 			0x00FD20DF
Vol+		0x00FD807F
VOL-		0x00FD906F
UP			0x00FD50AF
DOWN		0x00FD10EF
EQ			0x00FDB04F
0			0x00FD30CF
1			0x00FD08F7
2			0x00FD8877
3			0x00FD48B7

*/