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Diffstat (limited to 'source/ct-Bot/mcu/ir-rc5.c')
| -rw-r--r-- | source/ct-Bot/mcu/ir-rc5.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/source/ct-Bot/mcu/ir-rc5.c b/source/ct-Bot/mcu/ir-rc5.c new file mode 100644 index 0000000..8bb17b0 --- /dev/null +++ b/source/ct-Bot/mcu/ir-rc5.c @@ -0,0 +1,163 @@ +/*
+ * c't-Bot
+ *
+ * This program 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 2 of the License, or (at your
+ * option) any later version.
+ * This program 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 this program; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307, USA.
+ *
+ */
+
+/*! @file ir-rc5.c
+ * @brief Routinen für die Dekodierung von RC5-Fernbedienungs-Codes
+ * @author Benjamin Benz (bbe@heise.de)
+ * @date 20.12.05
+*/
+
+// Infos ueber RC6: http://www.xs4all.nl/~sbp/knowledge/ir/rc6.htm
+// http://www.xs4all.nl/~sbp/knowledge/ir/ir.htm
+
+// ========================================================================
+// RC5 Infrarot-Empf�nger
+// ========================================================================
+#include "ct-Bot.h"
+#ifdef MCU
+#ifdef IR_AVAILABLE
+
+#include <avr/io.h>
+#include "ir-rc5.h"
+#include "timer.h"
+
+
+// -----------------------------------------------------------------------------
+// Timing
+// -----------------------------------------------------------------------------
+#define IR_SAMPLES_PER_BIT 10 /*!< 10 Samples per Bit */
+#define IR_SAMPLES_PER_BIT_EARLY 8 /*!< Flanke fr�hestens nach 8 Samples */
+#define IR_SAMPLES_PER_BIT_LATE 12 /*!< Flanke sp�testens nach 12 Samples */
+#define IR_SAMPLES_PER_BIT_MIN 3 /*!< Flanke vor 3 Samples -> paket verwerfen */
+#define IR_PAUSE_SAMPLES 250 /*!< Startbit ist erst nach 250 Samples ohne */
+ // Pegel�nderung g�ltig -- eigentlich m�sste
+ // man rund 500 Samples abwarten (50 x
+ // Bitzeit), doch weil der Samplez�hler ein
+ // Byte ist, beschr�nken wir uns hier auf ein
+ // Minimum von 250 Samples
+
+#define IR_PORT PORTB /*!< Port B */
+#define IR_DDR DDRB /*!< DDR of Port B */
+#define IR_PINR PINB /*!< Port B input */
+#define IR_PIN 1 /*!< Pin 1 */
+
+
+
+static byte ir_lastsample = 0; /*!< zuletzt gelesenes Sample */
+static byte ir_bittimer = 0; /*!< zählt die Aufrufe von ir_isr() */
+
+static uint16 ir_data_tmp = 0; /*!< RC5-Bitstream */
+static byte ir_bitcount = 0; /*!< anzahl gelesener bits */
+
+volatile uint16 ir_data = 0; /*!< letztes komplett gelesenes RC5-paket */
+
+/*!
+ * Interrupt Serviceroutine
+ * wird ca alle 177.8us aufgerufen
+ */
+void ir_isr(void) {
+ // sample lesen
+ byte sample = 1;
+
+ if ((IR_PINR & (1<<IR_PIN)) != 0) {
+ sample = 0;
+ }
+
+ // bittimer erhoehen (bleibt bei 255 stehen)
+ if (ir_bittimer<255) {
+ ir_bittimer++;
+ }
+
+ // flankenerkennung
+ if ( ir_lastsample != sample) {
+ if (ir_bittimer<=IR_SAMPLES_PER_BIT_MIN) {
+ // flanke kommt zu frueh: paket verwerfen
+ ir_bitcount=0;
+ } else {
+ // Startbit
+ if (ir_bitcount==0) {
+ if ( (sample==1) && (ir_bittimer>IR_PAUSE_SAMPLES) ) {
+ // Startbit speichern
+ ir_data_tmp = 1;
+ ir_bitcount++;
+ } else {
+ // error
+ ir_data_tmp = 0;
+ }
+
+ // bittimer-reset
+ ir_bittimer = 0;
+
+ // Bits 2..14: nur Flanken innerhalb des Bits beruecksichtigen
+ } else {
+ if (ir_bittimer >= IR_SAMPLES_PER_BIT_EARLY) {
+ if(ir_bittimer<=IR_SAMPLES_PER_BIT_LATE){
+ // Bit speichern
+ ir_data_tmp = (ir_data_tmp<<1) | sample;
+ ir_bitcount++;
+ } else {
+ // zu sp�t: paket verwerfen
+ ir_bitcount = 0;
+ }
+
+ // bittimer-reset
+ ir_bittimer = 0;
+ }
+ }
+ }
+
+ } else {
+ // keine flanke innerhalb bitzeit?
+ if (ir_bittimer > IR_SAMPLES_PER_BIT_LATE) {
+ // 14 bits gelesen?
+ if (ir_bitcount==14) {
+ ir_data = ir_data_tmp;
+ }
+ // paket verwerfen
+ ir_bitcount = 0;
+ }
+ }
+
+ // sample im samplepuffer ablegen
+ ir_lastsample = sample;
+
+
+}
+
+
+/*!
+ * IR-Daten lesen
+ * @return wert von ir_data, löscht anschliessend ir_data
+ */
+uint16 ir_read(void) {
+ uint16 retvalue = ir_data;
+ ir_data = 0;
+ return retvalue;
+}
+
+/*!
+ * Init IR-System
+ */
+void ir_init(void) {
+ IR_DDR &= ~IR_PIN; // Pin auf Input
+ IR_PORT |= IR_PIN; // Pullup an
+ timer_2_init(); // Für IR-Krams
+}
+#endif
+#endif
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