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/*
* Copyright © 2011 Keith Packard <keithp@keithp.com>
*
* 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; version 2 of the License.
*
* 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.
*/
#include "ao.h"
volatile __xdata struct ao_adc ao_adc_ring[AO_ADC_RING];
volatile __data uint8_t ao_adc_head;
const uint8_t adc_channels[NUM_ADC] = {
0x00,
0x01,
0x04,
0x05,
0x06,
0x07,
0x20,
0x21,
0x22,
0x23,
0x24,
0x25,
};
static uint8_t ao_adc_channel;
#define ADC_CHANNEL_LOW(c) (((c) & 0x1f) << MUX0)
#define ADC_CHANNEL_HIGH(c) ((((c) & 0x20) >> 5) << MUX5)
#define ADCSRA_INIT ((1 << ADEN) | /* Enable ADC */ \
(0 << ADATE) | /* No auto ADC trigger */ \
(1 << ADIF) | /* Clear interrupt */ \
(0 << ADIE) | /* Enable interrupt */ \
(6 << ADPS0)) /* Prescale clock by 64 */
#define ADCSRB_INIT ((0 << ADHSM) | /* No high-speed mode */ \
(0 << ACME) | /* Some comparitor thing */ \
(2 << ADTS0)) /* Free running mode (don't care) */
static void
ao_adc_start(void)
{
uint8_t channel = adc_channels[ao_adc_channel];
ADMUX = ((0 << REFS1) | /* AVcc reference */
(1 << REFS0) | /* AVcc reference */
(1 << ADLAR) | /* Left-shift results */
(ADC_CHANNEL_LOW(channel))); /* Select channel */
ADCSRB = (ADCSRB_INIT |
ADC_CHANNEL_HIGH(channel)); /* High channel bit */
ADCSRA = (ADCSRA_INIT |
(1 << ADSC) |
(1 << ADIE)); /* Start conversion */
}
ISR(ADC_vect)
{
uint16_t value;
/* Must read ADCL first or the value there will be lost */
value = ADCL;
value |= (ADCH << 8);
ao_adc_ring[ao_adc_head].adc[ao_adc_channel] = value;
if (++ao_adc_channel < NUM_ADC)
ao_adc_start();
else {
ADCSRA = ADCSRA_INIT;
ao_adc_ring[ao_adc_head].tick = ao_time();
ao_adc_head = ao_adc_ring_next(ao_adc_head);
ao_wakeup((void *) &ao_adc_head);
ao_cpu_sleep_disable = 0;
}
}
void
ao_adc_poll(void)
{
ao_cpu_sleep_disable = 1;
ao_adc_channel = 0;
ao_adc_start();
}
void
ao_adc_get(__xdata struct ao_adc *packet)
{
uint8_t i = ao_adc_ring_prev(ao_adc_head);
memcpy(packet, (void *) &ao_adc_ring[i], sizeof (struct ao_adc));
}
static void
ao_adc_dump(void) __reentrant
{
static __xdata struct ao_adc packet;
uint8_t i;
ao_adc_get(&packet);
printf("tick: %5u", packet.tick);
for (i = 0; i < NUM_ADC; i++)
printf (" %2d: %5u", i, packet.adc[i]);
printf ("\n");
}
__code struct ao_cmds ao_adc_cmds[] = {
{ ao_adc_dump, "a\0Display current ADC values" },
{ 0, NULL },
};
void
ao_adc_init(void)
{
DIDR0 = 0xf3;
DIDR2 = 0x3f;
ADCSRB = ADCSRB_INIT;
ADCSRA = ADCSRA_INIT;
ao_cmd_register(&ao_adc_cmds[0]);
}
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