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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2007 by Dave Chapman
*
* 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "config.h"
#include "cpu.h"
#include "system.h"
#include "kernel.h"
#include "thread.h"
#include "string.h"
#include "adc.h"
static unsigned short adcdata[8];
#ifndef BOOTLOADER
/* Tick task */
static void adc_tick(void)
{
int i;
PCLK_ADC |= PCK_EN; /* Enable ADC clock */
/* Start converting the first 4 channels */
for (i = 0; i < 4; i++)
ADCCON = i;
}
/* IRQ handler */
void ADC(void)
{
int num;
uint32_t adc_status;
do
{
adc_status = ADCSTATUS;
num = (adc_status>>24) & 7;
if (num) adcdata[(adc_status >> 16) & 0x7] = adc_status & 0x3ff;
} while (num);
PCLK_ADC &= ~PCK_EN; /* Disable ADC clock */
}
#endif /* BOOTLOADER */
unsigned short adc_read(int channel)
{
#ifdef BOOTLOADER
/* IRQs aren't enabled in the bootloader - just do the read directly */
int i;
uint32_t adc_status;
PCLK_ADC |= PCK_EN; /* Enable ADC clock */
/* Start converting the first 4 channels */
for (i = 0; i < 4; i++)
ADCCON = i;
/* Now read the values back */
for (i=0; i < 4; i++)
{
/* Wait for data to become stable */
while ((ADCDATA & 0x1) == 0);
adc_status = ADCSTATUS;
adcdata[(adc_status >> 16) & 0x7] = adc_status & 0x3ff;
}
PCLK_ADC &= ~PCK_EN; /* Disable ADC clock */
#endif
return adcdata[channel];
}
void adc_init(void)
{
/* consider configuring PCK_ADC source here */
ADCCON = (1<<4); /* Enter standby mode */
ADCCFG |= 0x00000003; /* Single-mode, auto power-down */
#ifndef BOOTLOADER
ADCCFG |= (1<<3); /* Request IRQ on ADC completion */
IEN |= ADC_IRQ_MASK; /* Unmask ADC IRQs */
tick_add_task(adc_tick);
sleep(2); /* Ensure valid readings when adc_init returns */
#endif
}
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