ir-tx.c

/*  Copyright 2008 Stephen English, Jeffrey Gough, Alexis Johnson, 
        Robert Spanton and Joanna A. Sun.

    This file is part of the Formica robot firmware.

    The Formica robot firmware is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    The Formica robot firmware is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with the Formica robot firmware.  
    If not, see <http://www.gnu.org/licenses/>.  */
#include "ir-tx.h"
#include "device.h"
#include <signal.h>
#include "freq.h"
#include "ir-tx-data.h"
#include "ir.h"
#include "ir-rx.h"
#include "adc10.h"
#include "types.h"
#include "ir-bias.h"
#include "behav/parking.h"

/* Puts the timer into stop mode */
#define timer_b_dis() do { TBCTL &= ~MC_3; } while (0)
/* Puts the timer into up mode */
#define timer_b_en() do { TBCTL |= MC_UPTO_CCR0; } while (0)

static bool ir_tx_enabled = TRUE;

void ir_transmit_init( void )
{
	/* Configure timer B to perform the transmission */
	TBCTL = TBCLGRP_0 	/* Each TBCLx latch loads independently */
		| CNTL_0	/* 16-bit mode */
		| TBSSEL_SMCLK	/* Source Timer B from SMCLK */
		| ID_DIV1 	/* Divide by 1 */
		| MC_STOP;	/* Stopped for now */
		/* Interrupt disabled */

	/* CCR0 generates the IR TX signal */
	TBCCTL0 = CM_DISABLE 	/* No capture */
		| CCIS_2	/* GND */
		| SCS		/* Synchronize with the timer clock*/
		| CLLD_0	/* Load TBCL0 when TBCCR0 is written */
				/* (We only do this for the first write) */
		/* Compare mode */
		| OUTMOD_TOGGLE	/* Toggle the output when the compare matches */
		| CCIE;		/* Enable interrupt */

	/* TX is on pin P4.0 (TB0) */
	/* Connect TB0 to it */
	/* See page 71 of the MSP430F2234 datasheet: */
	P4DIR |= 1;
	P4SEL |= 1;
	
	TBCCR0 = 8000;
	/* Now only load TBCCR0 when TBR counts to 0 */
	TBCCTL0 |= CLLD_1;

	timer_b_en();
}

interrupt (TIMERB0_VECTOR) timer_b_isr(void)
{
	/* Which period we're in */
	static uint8_t period = 0;
	uint8_t sym;

	if( !ir_tx_enabled ) 
	{
	  //	adc10_grab();
		TBCCR0 = 32000;
		return;
	}

	/* Only change output period during the low section */
	if( P4IN & 1 )
		return;
	else
		/* LEDs currently off */
		adc10_grab();

	period++;
	/* Transmit 3 periods of each frequency */
	if( period != 4 )
		return;
	period = 0;

	sym = ir_tx_next_symbol();
	if( sym == INV_SYM )
	{
		/* No data: disable transmission */
		ir_tx_enabled = FALSE;
		/* Disable the compare unit's control of the IR */
		P4OUT &= ~1;
		P4SEL &= ~1;

		ir_receive_en();
	}
	else
		TBCCR0 = period_lut[ sym ];

	/* Flag is automatically cleared */
}

interrupt (TIMERB1_VECTOR) timer_b_isr2(void)
{
	/* This interrupt should never happen */
}

void ir_transmit_enable( void )
{
	ir_tx_enabled = TRUE;
	
	/* Enable compare unit control of IR unless parking*/
	if (now_parking)
	  P4SEL &= ~1;
	else
	  P4SEL |= 1;

	timer_b_en();

	ir_receive_dis();
}

bool ir_transmit_is_enabled( void )
{
	return ir_tx_enabled;
}