[tuxdroid-svn] r584 - firmware/tuxcore/trunk

[jaguarondi <c2m...@c2...>]

Author: jaguarondi
Date: 2007-10-08 13:48:05 +0200 (Mon, 08 Oct 2007)
New Revision: 584

Added:
   firmware/tuxcore/trunk/adc.c
   firmware/tuxcore/trunk/adc.h
Log:
* Forgot to include the adc module.


Added: firmware/tuxcore/trunk/adc.c
===================================================================
--- firmware/tuxcore/trunk/adc.c	                        (rev 0)
+++ firmware/tuxcore/trunk/adc.c	2007-10-08 11:48:05 UTC (rev 584)
@@ -0,0 +1,135 @@
+/*
+ * TUXCORE - Firmware for the 'core' CPU of tuxdroid
+ * Copyright (C) 2007 C2ME S.A. <tux...@c2...>
+ *
+ * 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
+ */
+
+/* $Id$ */
+
+/** \file adc.c
+    \brief ADC module
+    \ingroup adc
+*/
+
+#include <avr/interrupt.h>
+#include <avr/io.h>
+
+#include "adc.h"
+
+/** Union between 16 bits variables and the two 8 bits registers they're made
+ * of. */
+typedef union
+{
+    uint16_t w;
+    uint8_t b[2];
+} union16_t;
+
+/** Function pointer to the ADC ISR user function. */
+static void (*ADC_ISR_callback)(void);
+
+/**
+   \brief Set the user function which handles the ADC ISR
+   \param ADC_ISR_user_callback Function pointer to the user callback function.
+   \ingroup adc
+
+   This sets the user function which is called when the conversion completes.
+ */
+void ADC_set_ISR_callback(void (*ADC_ISR_user_callback)(void))
+{
+    ADC_ISR_callback = ADC_ISR_user_callback;
+}
+
+/**
+   \brief Initialize and enable the ADC module.
+   \ingroup adc
+ */
+void ADC_init()
+{
+    /* Enable ADC in single conversion mode. */
+    ADCSRA = _BV(ADEN) |
+     /* Enable ADC interrupt. */
+        _BV(ADIE) |
+     /* Set ADC prescaler to 128.
+     * Clock = F_CPU / 128 = 62.5kHz
+     * Sample rate = clock / 13 cycles = 4.8kHz (around 2ms). */
+        _BV(ADPS2) | _BV(ADPS1) | _BV(ADPS0);
+}
+
+/**
+   \brief Disable the ADC.
+   The ADC should be re-enabled with ADC_init(), which restores the prescaler.
+   \ingroup adc
+ */
+void ADC_disable()
+{
+    ADCSRA = 0;
+}
+
+/**
+   \brief Start a conversion on the selected channel.
+   \param ad_mux (ADMUX) Reference, format and channel selection.
+   \ingroup adc
+   
+   ADC Multiplexer Selection Register - ADMUX
+     Bit 7:6 - REFS1:0: Reference Selection Bits
+       0 0 AREF, Internal Vref turned off
+       0 1 AVCC with external capacitor at AREF pin
+       1 0 Reserved
+       1 1 Internal 1.1V Voltage Reference with external capacitor at AREF pin
+     Bit 5 - ADLAR: ADC Left Adjust Result
+     Bit 4 - Res: Reserved Bit
+     Bits 3:0 - MUX3:0: Analog Channel Selection Bits
+       0000 ADC0
+       0001 ADC1
+       0010 ADC2
+       0011 ADC3
+       0100 ADC4
+       0101 ADC5
+       0110 ADC6
+       0111 ADC7
+       1110 1.1V (VBG)
+       1111 0V (GND)
+*/
+void ADC_start(const uint8_t ad_mux)
+{
+    ADMUX = ad_mux;
+    ADCSRA |= _BV(ADSC);
+}
+
+/**
+   \brief Read the value of the last conversion.
+   \return Conversion result (10 bits).
+   \ingroup adc
+   You should ensure that the conversion is completed before reading the value.
+   */
+uint16_t ADC_read()
+{
+   union16_t adc_value; 
+    /* ADCH should be read after ADCL otherwise ADCL stays wite protected
+     * (c.f. datasheet). */
+    adc_value.b[0] = ADCL;
+    adc_value.b[1] = ADCH;
+    return adc_value.w;
+}
+
+/**
+   \brief ADC conversion interrupt
+   The callback function is called when the interrupt occurs.
+ */
+ISR(SIG_ADC)
+{
+    ADC_ISR_callback();
+}


Property changes on: firmware/tuxcore/trunk/adc.c
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Added: firmware/tuxcore/trunk/adc.h
===================================================================
--- firmware/tuxcore/trunk/adc.h	                        (rev 0)
+++ firmware/tuxcore/trunk/adc.h	2007-10-08 11:48:05 UTC (rev 584)
@@ -0,0 +1,43 @@
+/*
+ * TUXCORE - Firmware for the 'core' CPU of tuxdroid
+ * Copyright (C) 2007 C2ME S.A. <tux...@c2...>
+ *
+ * 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
+ */
+
+/* $Id$ */
+
+/** \file adc.h
+    \brief ADC module interface
+    \ingroup adc
+*/
+
+/** \defgroup adc ADC
+    The ADC module is the driver for the internal ADC of the AVR.
+*/
+
+#ifndef _ADC_H_
+#define _ADC_H_
+
+/*
+ * Interface
+ */
+void ADC_set_ISR_callback(void (*ADC_ISR_user_callback)(void));
+void ADC_init(void);
+void ADC_disable(void);
+void ADC_start(const uint8_t ad_mux);
+uint16_t ADC_read(void);
+
+#endif /* _ADC_H_ */


Property changes on: firmware/tuxcore/trunk/adc.h
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