2 * Copyright © 2017 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, either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
18 * ATtiny ADC interface
22 ao_adc_read(uint8_t mux)
29 /* Start conversion */
30 ADCSRA = ((1 << ADEN) |
39 /* Await conversion complete */
40 while ((ADCSRA & (1 << ADSC)) != 0)
47 return (((uint16_t) high) << 8) | low;