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;
24 const uint8_t adc_channels[NUM_ADC] = {
39 static uint8_t ao_adc_channel;
42 static uint16_t ao_adc_int_count;
43 static uint16_t ao_adc_int_error;
45 #define ADC_CHANNEL_LOW(c) (((c) & 0x1f) << MUX0)
46 #define ADC_CHANNEL_HIGH(c) ((((c) & 0x20) >> 5) << MUX5)
48 #define ADCSRA_INIT ((1 << ADEN) | /* Enable ADC */ \
49 (0 << ADATE) | /* No auto ADC trigger */ \
50 (1 << ADIF) | /* Clear interrupt */ \
51 (0 << ADIE) | /* Enable interrupt */ \
52 (6 << ADPS0)) /* Prescale clock by 64 */
54 #define ADCSRB_INIT ((0 << ADHSM) | /* No high-speed mode */ \
55 (0 << ACME) | /* Some comparitor thing */ \
56 (2 << ADTS0)) /* Free running mode (don't care) */
61 uint8_t channel = adc_channels[ao_adc_channel];
62 ADMUX = ((0 << REFS1) | /* AVcc reference */
63 (1 << REFS0) | /* AVcc reference */
64 (1 << ADLAR) | /* Left-shift results */
65 (ADC_CHANNEL_LOW(channel))); /* Select channel */
67 ADCSRB = (ADCSRB_INIT |
68 ADC_CHANNEL_HIGH(channel)); /* High channel bit */
70 ADCSRA = (ADCSRA_INIT |
72 (1 << ADIE)); /* Start conversion */
80 channel = (ADMUX & 0x1f) | (ADCSRB & 0x20);
81 if (adc_channels[ao_adc_channel] != channel)
85 ao_adc_ring[ao_adc_head].adc[ao_adc_channel] = value;
86 if (++ao_adc_channel < NUM_ADC)
90 ao_adc_ring[ao_adc_head].tick = ao_time();
91 ao_adc_head = ao_adc_ring_next(ao_adc_head);
92 ao_wakeup((void *) &ao_adc_head);
93 ao_cpu_sleep_disable = 0;
100 ao_cpu_sleep_disable = 1;
106 ao_adc_get(__xdata struct ao_adc *packet)
108 uint8_t i = ao_adc_ring_prev(ao_adc_head);
109 memcpy(packet, (void *) &ao_adc_ring[i], sizeof (struct ao_adc));
113 ao_adc_dump(void) __reentrant
115 static __xdata struct ao_adc packet;
117 printf ("interrupts: %u\n", ao_adc_int_count);
118 printf ("errors: %u\n", ao_adc_int_error);
120 printf ("ADMUX %02x ADCSRA %02x ADCSRB %02x\n",
121 ADMUX, ADCSRA, ADCSRB);
122 printf("tick: %5u", packet.tick);
123 for (i = 0; i < NUM_ADC; i++)
124 printf (" %5u", packet.adc[i]);
128 __code struct ao_cmds ao_adc_cmds[] = {
129 { ao_adc_dump, "a\0Display current ADC values" },
138 ADCSRB = ADCSRB_INIT;
139 ADCSRA = ADCSRA_INIT;
140 ao_cmd_register(&ao_adc_cmds[0]);