mirror of
https://github.com/qmk/qmk_firmware.git
synced 2024-11-23 20:03:01 +00:00
a8320f20f7
* Improve support and docs for ADC driver * Comment ADC channels * Move to Makers and Modders section, and fix usage instructions * Flesh out intro * Superscript 328P note * Fix pin_to_mux LUT * Support USB64/1287 as well * analogReadPin() defaults to 0V mux on invalid pin * Update pinToMux() function documentation * Dot * Accept (some of) the `qmk cformat` changes * Do clang-format properly * More wording tweaks * Link to encoder docs
133 lines
5.1 KiB
C
133 lines
5.1 KiB
C
/* 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__)
|
|
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__)
|
|
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
|
|
}
|
|
}
|
|
|
|
int16_t adc_read(uint8_t mux) {
|
|
uint8_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!
|
|
return (ADCH << 8) | low;
|
|
}
|