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Diffstat (limited to 'platforms/avr/drivers/analog.c')
| -rw-r--r-- | platforms/avr/drivers/analog.c | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/platforms/avr/drivers/analog.c b/platforms/avr/drivers/analog.c new file mode 100644 index 0000000000..8d299ffdb9 --- /dev/null +++ b/platforms/avr/drivers/analog.c @@ -0,0 +1,138 @@ +/* Copyright 2015 Jack Humbert + * + * 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 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, see <http://www.gnu.org/licenses/>. + */ + +#include <avr/io.h> +#include <avr/pgmspace.h> +#include <stdint.h> +#include "analog.h" + +static uint8_t aref = ADC_REF_POWER; + +void analogReference(uint8_t mode) { aref = mode & (_BV(REFS1) | _BV(REFS0)); } + +// Arduino compatible pin input +int16_t analogRead(uint8_t pin) { +#if defined(__AVR_ATmega32U4__) + // clang-format off + static const uint8_t PROGMEM pin_to_mux[] = { + //A0 A1 A2 A3 A4 A5 + //F7 F6 F5 F4 F1 F0 + 0x07, 0x06, 0x05, 0x04, 0x01, 0x00, + //A6 A7 A8 A9 A10 A11 + //D4 D7 B4 B5 B6 D6 + 0x20, 0x22, 0x23, 0x24, 0x25, 0x21 + }; + // clang-format on + if (pin >= 12) return 0; + return adc_read(pgm_read_byte(pin_to_mux + pin)); +#elif defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__) || defined(__AVR_ATmega328P__) || defined(__AVR_ATmega328__) + if (pin >= 8) return 0; + return adc_read(pin); +#else + return 0; +#endif +} + +int16_t analogReadPin(pin_t pin) { return adc_read(pinToMux(pin)); } + +uint8_t pinToMux(pin_t pin) { + switch (pin) { + // clang-format off +#if defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__) + case F0: return 0; // ADC0 + case F1: return _BV(MUX0); // ADC1 + case F2: return _BV(MUX1); // ADC2 + case F3: return _BV(MUX1) | _BV(MUX0); // ADC3 + case F4: return _BV(MUX2); // ADC4 + case F5: return _BV(MUX2) | _BV(MUX0); // ADC5 + case F6: return _BV(MUX2) | _BV(MUX1); // ADC6 + case F7: return _BV(MUX2) | _BV(MUX1) | _BV(MUX0); // ADC7 + default: return _BV(MUX4) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1) | _BV(MUX0); // 0V +#elif defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__) + case F0: return 0; // ADC0 + case F1: return _BV(MUX0); // ADC1 + case F4: return _BV(MUX2); // ADC4 + case F5: return _BV(MUX2) | _BV(MUX0); // ADC5 + case F6: return _BV(MUX2) | _BV(MUX1); // ADC6 + case F7: return _BV(MUX2) | _BV(MUX1) | _BV(MUX0); // ADC7 + case D4: return _BV(MUX5); // ADC8 + case D6: return _BV(MUX5) | _BV(MUX0); // ADC9 + case D7: return _BV(MUX5) | _BV(MUX1); // ADC10 + case B4: return _BV(MUX5) | _BV(MUX1) | _BV(MUX0); // ADC11 + case B5: return _BV(MUX5) | _BV(MUX2); // ADC12 + case B6: return _BV(MUX5) | _BV(MUX2) | _BV(MUX0); // ADC13 + default: return _BV(MUX4) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1) | _BV(MUX0); // 0V +#elif defined(__AVR_ATmega32A__) + case A0: return 0; // ADC0 + case A1: return _BV(MUX0); // ADC1 + case A2: return _BV(MUX1); // ADC2 + case A3: return _BV(MUX1) | _BV(MUX0); // ADC3 + case A4: return _BV(MUX2); // ADC4 + case A5: return _BV(MUX2) | _BV(MUX0); // ADC5 + case A6: return _BV(MUX2) | _BV(MUX1); // ADC6 + case A7: return _BV(MUX2) | _BV(MUX1) | _BV(MUX0); // ADC7 + default: return _BV(MUX4) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1) | _BV(MUX0); // 0V +#elif defined(__AVR_ATmega328P__) || defined(__AVR_ATmega328__) + case C0: return 0; // ADC0 + case C1: return _BV(MUX0); // ADC1 + case C2: return _BV(MUX1); // ADC2 + case C3: return _BV(MUX1) | _BV(MUX0); // ADC3 + case C4: return _BV(MUX2); // ADC4 + case C5: return _BV(MUX2) | _BV(MUX0); // ADC5 + // ADC7:6 not present in DIP package and not shared by GPIO pins + default: return _BV(MUX3) | _BV(MUX2) | _BV(MUX1) | _BV(MUX0); // 0V +#endif + // clang-format on + } + return 0; +} + +int16_t adc_read(uint8_t mux) { + uint16_t low; + + // Enable ADC and configure prescaler + ADCSRA = _BV(ADEN) | ADC_PRESCALER; + +#if defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__) + // High speed mode and ADC8-13 + ADCSRB = _BV(ADHSM) | (mux & _BV(MUX5)); +#elif defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__) + // High speed mode only + ADCSRB = _BV(ADHSM); +#endif + + // Configure mux input +#if defined(MUX4) + ADMUX = aref | (mux & (_BV(MUX4) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1) | _BV(MUX0))); +#else + ADMUX = aref | (mux & (_BV(MUX3) | _BV(MUX2) | _BV(MUX1) | _BV(MUX0))); +#endif + + // Start the conversion + ADCSRA |= _BV(ADSC); + // Wait for result + while (ADCSRA & _BV(ADSC)) + ; + // Must read LSB first + low = ADCL; + // Must read MSB only once! + low |= (ADCH << 8); + + // turn off the ADC + ADCSRA &= ~(1 << ADEN); + + return low; +} |