164 lines
4.4 KiB
C
164 lines
4.4 KiB
C
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/*
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* c't-Bot
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*
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* This program is free software; you can redistribute it
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* and/or modify it under the terms of the GNU General
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* Public License as published by the Free Software
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* Foundation; either version 2 of the License, or (at your
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* option) any later version.
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* This program is distributed in the hope that it will be
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* useful, but WITHOUT ANY WARRANTY; without even the implied
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* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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* PURPOSE. See the GNU General Public License for more details.
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the Free
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* Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307, USA.
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*
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*/
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/*! @file ir-rc5.c
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* @brief Routinen für die Dekodierung von RC5-Fernbedienungs-Codes
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* @author Benjamin Benz (bbe@heise.de)
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* @date 20.12.05
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*/
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// Infos ueber RC6: http://www.xs4all.nl/~sbp/knowledge/ir/rc6.htm
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// http://www.xs4all.nl/~sbp/knowledge/ir/ir.htm
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// ========================================================================
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// RC5 Infrarot-Empf<70>nger
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// ========================================================================
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#include "ct-Bot.h"
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#ifdef MCU
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#ifdef IR_AVAILABLE
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#include <avr/io.h>
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#include "ir-rc5.h"
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#include "timer.h"
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// -----------------------------------------------------------------------------
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// Timing
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// -----------------------------------------------------------------------------
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#define IR_SAMPLES_PER_BIT 10 /*!< 10 Samples per Bit */
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#define IR_SAMPLES_PER_BIT_EARLY 8 /*!< Flanke fr<66>hestens nach 8 Samples */
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#define IR_SAMPLES_PER_BIT_LATE 12 /*!< Flanke sp<73>testens nach 12 Samples */
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#define IR_SAMPLES_PER_BIT_MIN 3 /*!< Flanke vor 3 Samples -> paket verwerfen */
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#define IR_PAUSE_SAMPLES 250 /*!< Startbit ist erst nach 250 Samples ohne */
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// Pegel<65>nderung g<>ltig -- eigentlich m<>sste
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// man rund 500 Samples abwarten (50 x
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// Bitzeit), doch weil der Samplez<65>hler ein
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// Byte ist, beschr<68>nken wir uns hier auf ein
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// Minimum von 250 Samples
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#define IR_PORT PORTB /*!< Port B */
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#define IR_DDR DDRB /*!< DDR of Port B */
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#define IR_PINR PINB /*!< Port B input */
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#define IR_PIN 1 /*!< Pin 1 */
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static byte ir_lastsample = 0; /*!< zuletzt gelesenes Sample */
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static byte ir_bittimer = 0; /*!< zählt die Aufrufe von ir_isr() */
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static uint16 ir_data_tmp = 0; /*!< RC5-Bitstream */
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static byte ir_bitcount = 0; /*!< anzahl gelesener bits */
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volatile uint16 ir_data = 0; /*!< letztes komplett gelesenes RC5-paket */
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/*!
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* Interrupt Serviceroutine
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* wird ca alle 177.8us aufgerufen
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*/
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void ir_isr(void) {
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// sample lesen
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byte sample = 1;
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if ((IR_PINR & (1<<IR_PIN)) != 0) {
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sample = 0;
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}
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// bittimer erhoehen (bleibt bei 255 stehen)
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if (ir_bittimer<255) {
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ir_bittimer++;
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}
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// flankenerkennung
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if ( ir_lastsample != sample) {
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if (ir_bittimer<=IR_SAMPLES_PER_BIT_MIN) {
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// flanke kommt zu frueh: paket verwerfen
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ir_bitcount=0;
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} else {
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// Startbit
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if (ir_bitcount==0) {
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if ( (sample==1) && (ir_bittimer>IR_PAUSE_SAMPLES) ) {
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// Startbit speichern
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ir_data_tmp = 1;
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ir_bitcount++;
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} else {
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// error
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ir_data_tmp = 0;
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}
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// bittimer-reset
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ir_bittimer = 0;
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// Bits 2..14: nur Flanken innerhalb des Bits beruecksichtigen
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} else {
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if (ir_bittimer >= IR_SAMPLES_PER_BIT_EARLY) {
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if(ir_bittimer<=IR_SAMPLES_PER_BIT_LATE){
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// Bit speichern
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ir_data_tmp = (ir_data_tmp<<1) | sample;
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ir_bitcount++;
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} else {
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// zu sp<73>t: paket verwerfen
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ir_bitcount = 0;
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}
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// bittimer-reset
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ir_bittimer = 0;
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}
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}
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}
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} else {
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// keine flanke innerhalb bitzeit?
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if (ir_bittimer > IR_SAMPLES_PER_BIT_LATE) {
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// 14 bits gelesen?
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if (ir_bitcount==14) {
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ir_data = ir_data_tmp;
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}
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// paket verwerfen
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ir_bitcount = 0;
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}
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}
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// sample im samplepuffer ablegen
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ir_lastsample = sample;
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}
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/*!
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* IR-Daten lesen
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* @return wert von ir_data, löscht anschliessend ir_data
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*/
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uint16 ir_read(void) {
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uint16 retvalue = ir_data;
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ir_data = 0;
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return retvalue;
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}
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/*!
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* Init IR-System
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*/
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void ir_init(void) {
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IR_DDR &= ~IR_PIN; // Pin auf Input
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IR_PORT |= IR_PIN; // Pullup an
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timer_2_init(); // Für IR-Krams
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}
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#endif
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#endif
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