diff options
Diffstat (limited to 'drivers/avr/analog.c')
| -rw-r--r-- | drivers/avr/analog.c | 53 |
1 files changed, 21 insertions, 32 deletions
diff --git a/drivers/avr/analog.c b/drivers/avr/analog.c index 1ec38df75d..1a8da4261d 100644 --- a/drivers/avr/analog.c +++ b/drivers/avr/analog.c @@ -21,49 +21,38 @@ #include <stdint.h> #include "analog.h" +static uint8_t aref = (1 << REFS0); // default to AREF = Vcc -static uint8_t aref = (1<<REFS0); // default to AREF = Vcc - - -void analogReference(uint8_t mode) -{ - aref = mode & 0xC0; -} - +void analogReference(uint8_t mode) { aref = mode & 0xC0; } // Arduino compatible pin input -int16_t analogRead(uint8_t pin) -{ +int16_t analogRead(uint8_t pin) { #if defined(__AVR_ATmega32U4__) - static const uint8_t PROGMEM pin_to_mux[] = { - 0x00, 0x01, 0x04, 0x05, 0x06, 0x07, - 0x25, 0x24, 0x23, 0x22, 0x21, 0x20}; - if (pin >= 12) return 0; - return adc_read(pgm_read_byte(pin_to_mux + pin)); + static const uint8_t PROGMEM pin_to_mux[] = {0x00, 0x01, 0x04, 0x05, 0x06, 0x07, 0x25, 0x24, 0x23, 0x22, 0x21, 0x20}; + if (pin >= 12) return 0; + return adc_read(pgm_read_byte(pin_to_mux + pin)); #elif defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB1286__) - if (pin >= 8) return 0; - return adc_read(pin); + if (pin >= 8) return 0; + return adc_read(pin); #else - return 0; + return 0; #endif } // Mux input -int16_t adc_read(uint8_t mux) -{ +int16_t adc_read(uint8_t mux) { #if defined(__AVR_AT90USB162__) - return 0; + return 0; #else - uint8_t low; - - ADCSRA = (1<<ADEN) | ADC_PRESCALER; // enable ADC - ADCSRB = (1<<ADHSM) | (mux & 0x20); // high speed mode - ADMUX = aref | (mux & 0x1F); // configure mux input - ADCSRA = (1<<ADEN) | ADC_PRESCALER | (1<<ADSC); // start the conversion - while (ADCSRA & (1<<ADSC)) ; // wait for result - low = ADCL; // must read LSB first - return (ADCH << 8) | low; // must read MSB only once! + uint8_t low; + + ADCSRA = (1 << ADEN) | ADC_PRESCALER; // enable ADC + ADCSRB = (1 << ADHSM) | (mux & 0x20); // high speed mode + ADMUX = aref | (mux & 0x1F); // configure mux input + ADCSRA = (1 << ADEN) | ADC_PRESCALER | (1 << ADSC); // start the conversion + while (ADCSRA & (1 << ADSC)) + ; // wait for result + low = ADCL; // must read LSB first + return (ADCH << 8) | low; // must read MSB only once! #endif } - - |