MSP430 IR Serial Demo

IR_Rcvr.c

// Simple IR Receiver
// Kenneth Finnegan, 2011
// kennethfinnegan.blogspot.com
//
// Pinout:
// P1.[0..7] - Common anode 7 segment display w/ decimal
// P2.5 - 38kHz IR receiver

#include <msp430g2252.h>

#define EN_DECIMAL_PT	0x7F
#define DIS_DECIMAL_PT	0xFF
#define BEAT_FREQ		512
#define BUTDEB_LEN		(BEAT_FREQ / 4)
#define MAX_STATE		9
#define STATE_LEN		4
#define ERROR_STATE		0x0A

// xmit - flag to start 38kHz IR LED modulation
// xmitstate - state machine for serial protocol
// currstate - currently selected digit [0-9]
// decimalmask - mask to set or clear decimal point
// butdeb - Button debounce counters
volatile unsigned int currstate=ERROR_STATE, rcvrstate = 0, newstate = 0,
		decimalmask = DIS_DECIMAL_PT, stateage = 0;

// Seven segment bit fields.  Active low. {[0-9] E(rror)}
unsigned const char digits[] = {	0x82, 0xBB, 0xA4, 0xA1, 0x99, 
								0xC1, 0xC0, 0xAB, 0x80, 0x89, 0xC4 };

void main(void) {
	WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
	BCSCTL1 = CALBC1_1MHZ;
    DCOCTL = CALDCO_1MHZ;
	
	P1DIR = 0xFF; // Set P1 to output direction
	P1OUT = 0xFF; // Set the LEDs off
	P2DIR = 0xDF; // Set P2.5 to input for buttons
	P2OUT = 0x00;
	P2IES = 0x20; // Negative edge trigger
	P2IFG = 0x00;
	P2IE  = 0x20; // Enable button interrupts
	
	TACTL = TASSEL_1 | MC_1; // Set the timer A to ACLK, Up mode
	TACCR0 = (0x8000 / BEAT_FREQ) - 1; // Reset timer at BEAT frequency
	TACCTL0 = CCIE; // Clear the timer and enable timer interrupt
	
	__enable_interrupt();
	
	_BIS_SR(LPM1_bits + GIE);
}

// Timer A0 interrupt service routine
// Heartbeat interrupt
#pragma vector=TIMER0_A0_VECTOR
__interrupt void Timer0_A0 (void)
{
	stateage++;
	// If we haven't seen an update in two cycles, something's wrong
	if (stateage > 2 * BEAT_FREQ) {
		currstate = ERROR_STATE;
	}
	decimalmask = DIS_DECIMAL_PT;
	if (rcvrstate > 1) decimalmask = EN_DECIMAL_PT;
	P1OUT = digits[currstate] & decimalmask;
}

// Timer A1 interrupt service routine
// Sampling pulse for IR data 
#pragma vector=TIMER0_A1_VECTOR
__interrupt void Timer_A1 (void)
{
	P2OUT ^= 0x01; // Debug tick
	if (rcvrstate == 1) { // Test for START bit
		if (P2IN & 0x20) { // No start bit
			rcvrstate = 0;
			P2IE |= 0x20;
			TACCTL1 = 0;
		}
	} else if (rcvrstate == STATE_LEN + 2) { // Test for STOP bit
		if (P2IN & 0x20) { // No stop bit
			rcvrstate = 0;
			P2IE |= 0x20;
			TACCTL1 = 0;
		}
	} else if (rcvrstate == STATE_LEN + 3) { // Finish receive
		rcvrstate = 0;
		P2IE |= 0x20;
		TACCTL1 = 0;
		currstate = newstate;
		stateage = 0;
	} else { // State bit
		newstate = (newstate << 1) | ((P2IN >> 5) & 0x01);
	}
	rcvrstate++;
	TAIV &= ~(0x02); // CLEAR INTERRUPT
}

#pragma vector=PORT2_VECTOR
__interrupt void Port2 (void) {
	// Start bit edge
	if (P2IFG & 0x20) {
		rcvrstate = 1; // Begin receive
		newstate = 0;
		// Set Timer0A1 to half a beat later
		TACCR1 = (TAR + (0x8000 / 2 / BEAT_FREQ)) % (TACCR0 + 1);
		TACCTL1 = CCIE;
		// Turn off edge interrupt
		P2IE &= ~0x20;
	}
	P2IFG = 0x00;
}

IR_Xmit.c

// Simple IR Transmitter
// Kenneth Finnegan, 2011
// kennethfinnegan.blogspot.com
//
// Pinout:
// P1.[0..7] - Common anode 7 segment display w/ decimal
// P2.0 - Increment state button
// P2.1 - Decrement state button
// P2.5 - IR LED OUTPUT

#include <msp430g2252.h>

#define EN_DECIMAL_PT	0x7F
#define DIS_DECIMAL_PT	0xFF
#define BEAT_FREQ		512
#define BUTDEB_LEN		(BEAT_FREQ / 4)
#define MAX_STATE		9
#define STATE_LEN		4

// xmit - flag to start 38kHz IR LED modulation
// xmitstate - state machine for serial protocol
// currstate - currently selected digit [0-9]
// decimalmask - mask to set or clear decimal point
// butdeb - Button debounce counters
volatile int xmit=0, xmitstate=0, currstate=0, savestate=0,
			decimalmask = DIS_DECIMAL_PT, butdeb[2] = {0,0};

// Seven segment bit fields.  Active low. {[0-9] E(rror)}
unsigned const char digits[] = {	0x82, 0xBB, 0xA4, 0xA1, 0x99, 
								0xC1, 0xC0, 0xAB, 0x80, 0x89, 0xC4 };

void main(void) {
	WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
	BCSCTL1 = CALBC1_1MHZ;
    DCOCTL = CALDCO_1MHZ;
	
	P1DIR = 0xFF; // Set P1 to output direction
	P1OUT = 0xFF; // Set the LEDs off
	P2DIR = 0xFC; // Set P2.0/1 to input for buttons
	P2OUT = 0x20; // Set IR LED off
	P2REN = 0x03; // Enable pulldown resistors
	P2IES = 0x03; // Positive edge trigger
	P2IFG = 0x00; // Clear pin change interrupt flags
	P2IE  = 0x03; // Enable button interrupts
	
	TACTL = TASSEL_1 | MC_1; // Set the timer A to ACLK, Up mode
	TACCR0 = (0x8000 / BEAT_FREQ) - 1; // Reset timer at BEAT frequency
	TACCTL0 = CCIE; // Clear the timer and enable timer interrupt
	
	__enable_interrupt();
	
	while(1) {
		while(xmit) {
			// Delay some cycles to keep frequency at 38kHz
			// This is much less than expected due to the
			// lost time to the while loop's condition test
			// and the bitwise math on P2OUT
			// This value was found with an oscilloscope.
			__delay_cycles(2);
			P2OUT ^= BIT5;
		}
		// Turn off IR LED
		P2OUT &= ~BIT5;
	}
}

// Timer A0 interrupt service routine
#pragma vector=TIMER0_A0_VECTOR
__interrupt void Timer0_A0 (void)
{
	xmitstate = (xmitstate + 1) % BEAT_FREQ;
	
	// Set transmit flag for START BIT3 BIT2 BIT1 BIT0 STOP
	if (xmitstate == 0 || xmitstate == (STATE_LEN + 1)) { // START & STOP bits
		xmit = 1;
		decimalmask = EN_DECIMAL_PT;
		savestate = currstate; // Prevent state from changing during xmit
	} else if (xmitstate < (STATE_LEN + 1)) { // 4 bits of state MSBF
		xmit = !((savestate >> (STATE_LEN - xmitstate)) & 0x1);
	} else {
		xmit = 0;
		decimalmask = DIS_DECIMAL_PT;
	}
	// Update display
	P1OUT = digits[currstate] & decimalmask;
	// Decrement debounce counters, but only to zero
	butdeb[0]?butdeb[0]--:1;
	butdeb[1]?butdeb[1]--:1;
}

#pragma vector=PORT2_VECTOR
__interrupt void Port2 (void) {
	// Increment state
	if ((P2IFG & 0x02) && !butdeb[1]) {
		butdeb[1] = BUTDEB_LEN;
		currstate = (currstate+1) % (MAX_STATE + 1);
	}
	// Decrement state
	if ((P2IFG & 0x01) && !butdeb[0]) {
		butdeb[0] = BUTDEB_LEN;
		currstate = currstate ? (currstate - 1) : MAX_STATE;
	}
	P2IFG = 0x00;
}

hi,
i have a problem in your code:
TAIV &= ~(0x02); - Error[Pe137]: expression must be a modifiable lvalue.
can you help me?
i'm using IAR.
Thank you.

Can i get circuit diagram for this
because i am not getting output

Can i get circuit diagram for this because i am not getting output

can u get diagram???