From 19b7242bcbc2902d5457c386f933c78fa39b6553 Mon Sep 17 00:00:00 2001
From: asterix <asterix@38d2e660-2303-0410-9eaa-f027e97ec537>
Date: Wed, 16 Jan 2008 16:16:45 +0000
Subject: [PATCH] Add ADC module for avr.

git-svn-id: https://src.develer.com/svnoss/bertos/trunk@1050 38d2e660-2303-0410-9eaa-f027e97ec537
---
 cpu/avr/drv/adc_avr.c | 153 ++++++++++++++++++++++++++++++++++++++++++
 cpu/avr/drv/adc_avr.h |  21 ++++++
 2 files changed, 174 insertions(+)
 create mode 100644 cpu/avr/drv/adc_avr.c
 create mode 100644 cpu/avr/drv/adc_avr.h

diff --git a/cpu/avr/drv/adc_avr.c b/cpu/avr/drv/adc_avr.c
new file mode 100644
index 00000000..e57b04bf
--- /dev/null
+++ b/cpu/avr/drv/adc_avr.c
@@ -0,0 +1,153 @@
+/*!
+ * \file
+ * <!--
+ * Copyright 2007 Develer S.r.l. (http://www.develer.com/)
+ * -->
+ *
+ * \version $Id$
+ *
+ * \brief ADC hardware-specific definition
+ *
+ * \version $Id$
+ * \author Francesco Sacchi <batt@develer.com>
+ */
+
+#include "adc_avr.h"
+
+#include <drv/adc.h>
+#include <appconfig.h>
+
+#include <cfg/macros.h>
+#include <cfg/compiler.h>
+
+#include <avr/io.h>
+#include <avr/interrupt.h>
+
+#define ADC_AVR_AREF   0
+#define ADC_AVR_AVCC   1
+#define ADC_AVR_INT256 2
+
+#if CONFIG_KERNEL
+	#include <cfg/module.h>
+	#include <config_kern.h>
+	#include <kern/proc.h>
+	#include <kern/signal.h>
+
+
+	#if !CONFIG_KERN_SIGNALS
+		#error Signals must be active to use ADC with kernel
+	#endif
+
+	/* Signal adc convertion end */
+	#define SIG_ADC_COMPLETE SIG_SINGLE
+
+	/* ADC waiting process */
+	static struct Process *adc_process;
+
+	/**
+	 * ADC ISR.
+	 * Simply signal the adc process that convertion is complete.
+	 */
+	ISR(ADC_vect)
+	{
+		sig_signal(adc_process, SIG_ADC_COMPLETE);
+	}
+#endif /* CONFIG_KERNEL */
+
+/**
+ * Select mux channel \a ch.
+ * \todo only first 8 channels are selectable!
+ */
+INLINE void adc_hw_select_ch(uint8_t ch)
+{
+	/* Set to 0 all mux registers */
+	ADMUX &= ~(BV(MUX3) | BV(MUX3) | BV(MUX2) | BV(MUX1) | BV(MUX0));
+
+	/* Select channel, only first 8 channel modes are supported for now */
+	ADMUX |= (ch & 0x07);
+}
+
+
+/**
+ * Start an ADC convertion.
+ * If a kernel is present, preempt until convertion is complete, otherwise
+ * a busy wait on ADCS bit is done.
+ */
+INLINE uint16_t adc_hw_read(void)
+{
+	// Ensure another convertion is not running.
+	ASSERT(!(ADCSRA & BV(ADSC)));
+
+	// Start convertion
+	ADCSRA |= BV(ADSC);
+
+	#if CONFIG_KERNEL
+		// Ensure IRQs enabled.
+		ASSERT(IRQ_ENABLED());
+		adc_process = proc_current();
+		sig_wait(SIG_ADC_COMPLETE);
+	#else
+		//Wait in polling until is done
+		while (ADCSRA & BV(ADSC)) ;
+	#endif
+
+	return(ADC);
+}
+
+/**
+ * Init ADC hardware.
+ */
+INLINE void adc_hw_init(void)
+{
+	/*
+	 * Select channel 0 as default,
+	 * result right adjusted.
+	 */
+	ADMUX = 0;
+
+	#if CONFIG_ADC_AVR_REF == ADC_AVR_AREF
+		/* External voltage at AREF as analog ref source */
+		/* None */
+	#elif CONFIG_ADC_AVR_REF == ADC_AVR_AVCC
+		/* AVCC as analog ref source */
+		ADMUX |= BV(REFS0);
+	#elif CONFIG_ADC_AVR_REF == ADC_AVR_INT256
+		/* Internal 2.56V as ref source */
+		ADMUX |= BV(REFS1) | BV(REFS0);
+	#else
+		#error Unsupported ADC ref value.
+	#endif
+
+	/* Disable Auto trigger source: ADC in Free running mode. */
+	ADCSRB = 0;
+	
+	/* Enable ADC, disable autotrigger mode. */
+	ADCSRA = BV(ADEN);
+
+	#if CONFIG_KERNEL
+		MOD_CHECK(proc);
+		ADCSRA |= BV(ADIE);
+	#endif
+
+	/* Set convertion frequency */
+	#if CONFIG_ADC_AVR_DIVISOR == 2
+		ADCSRA |= BV(ADPS0);
+	#elif CONFIG_ADC_AVR_DIVISOR == 4
+		ADCSRA |= BV(ADPS1);
+	#elif CONFIG_ADC_AVR_DIVISOR == 8
+		ADCSRA |= BV(ADPS1) | BV(ADPS0);
+	#elif CONFIG_ADC_AVR_DIVISOR == 16
+		ADCSRA |= BV(ADPS2);
+	#elif CONFIG_ADC_AVR_DIVISOR == 32
+		ADCSRA |= BV(ADPS2) | BV(ADPS0);
+	#elif CONFIG_ADC_AVR_DIVISOR == 64
+		ADCSRA |= BV(ADPS2) | BV(ADPS1);
+	#elif CONFIG_ADC_AVR_DIVISOR == 128
+		ADCSRA |= BV(ADPS2) | BV(ADPS1) | BV(ADPS0);
+	#else
+		#error Unsupported ADC prescaler value.
+	#endif
+
+	/* Start a convertion to init ADC hw */
+	adc_hw_read();
+}
diff --git a/cpu/avr/drv/adc_avr.h b/cpu/avr/drv/adc_avr.h
new file mode 100644
index 00000000..ddd2ce72
--- /dev/null
+++ b/cpu/avr/drv/adc_avr.h
@@ -0,0 +1,21 @@
+/*!
+ * \file
+ * <!--
+ * Copyright 2007 Develer S.r.l. (http://www.develer.com/)
+ * -->
+ *
+ * \version $Id$
+ *
+ * \brief ADC hardware-specific definition
+ *
+ * \version $Id$
+ * \author Francesco Sacchi <batt@develer.com>
+ */
+
+#ifndef DRV_ADC_AVR_H
+#define DRV_ADC_AVR_H
+
+#define ADC_MUX_MAXCH 7
+#define ADC_BITS      10
+
+#endif /* DRV_ADC_AVR_H */
-- 
2.34.1