2 * Copyright © 2011 Keith Packard <keithp@keithp.com>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; version 2 of the License.
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
20 volatile __xdata struct ao_adc ao_adc_ring[AO_ADC_RING];
21 volatile __data uint8_t ao_adc_head;
23 const uint8_t adc_channels[NUM_ADC] = {
38 static uint8_t ao_adc_channel;
40 #define ADC_CHANNEL_LOW(c) (((c) & 0x1f) << MUX0)
41 #define ADC_CHANNEL_HIGH(c) ((((c) & 0x20) >> 5) << MUX5)
43 #define ADCSRA_INIT ((1 << ADEN) | /* Enable ADC */ \
44 (0 << ADATE) | /* No auto ADC trigger */ \
45 (1 << ADIF) | /* Clear interrupt */ \
46 (0 << ADIE) | /* Enable interrupt */ \
47 (6 << ADPS0)) /* Prescale clock by 64 */
49 #define ADCSRB_INIT ((0 << ADHSM) | /* No high-speed mode */ \
50 (0 << ACME) | /* Some comparitor thing */ \
51 (2 << ADTS0)) /* Free running mode (don't care) */
56 uint8_t channel = adc_channels[ao_adc_channel];
57 ADMUX = ((0 << REFS1) | /* AVcc reference */
58 (1 << REFS0) | /* AVcc reference */
59 (1 << ADLAR) | /* Left-shift results */
60 (ADC_CHANNEL_LOW(channel))); /* Select channel */
62 ADCSRB = (ADCSRB_INIT |
63 ADC_CHANNEL_HIGH(channel)); /* High channel bit */
65 ADCSRA = (ADCSRA_INIT |
67 (1 << ADIE)); /* Start conversion */
74 /* Must read ADCL first or the value there will be lost */
77 ao_adc_ring[ao_adc_head].adc[ao_adc_channel] = value;
78 if (++ao_adc_channel < NUM_ADC)
82 ao_adc_ring[ao_adc_head].tick = ao_time();
83 ao_adc_head = ao_adc_ring_next(ao_adc_head);
84 ao_wakeup((void *) &ao_adc_head);
85 ao_cpu_sleep_disable = 0;
92 ao_cpu_sleep_disable = 1;
98 ao_adc_get(__xdata struct ao_adc *packet)
100 uint8_t i = ao_adc_ring_prev(ao_adc_head);
101 memcpy(packet, (void *) &ao_adc_ring[i], sizeof (struct ao_adc));
105 ao_adc_dump(void) __reentrant
107 static __xdata struct ao_adc packet;
110 printf("tick: %5u", packet.tick);
111 for (i = 0; i < NUM_ADC; i++)
112 printf (" %2d: %5u", i, packet.adc[i]);
116 __code struct ao_cmds ao_adc_cmds[] = {
117 { ao_adc_dump, "a\0Display current ADC values" },
126 ADCSRB = ADCSRB_INIT;
127 ADCSRA = ADCSRA_INIT;
128 ao_cmd_register(&ao_adc_cmds[0]);