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authorfauxpark <fauxpark@gmail.com>2019-12-08 12:11:29 +1100
committerFlorian Didron <fdidron@users.noreply.github.com>2020-01-09 08:57:11 +0900
commitffc0605370c5b30551f379494202e52b7cb7ee96 (patch)
tree172feb4de5f41f0d0ceece71a926a6f5865b6c2d
parent5a5c90f8519a42bde253d1be5494b1704c2491c2 (diff)
Improve support and docs for ADC driver (#7191)
* 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
-rw-r--r--drivers/avr/analog.c110
-rw-r--r--drivers/avr/analog.h37
2 files changed, 108 insertions, 39 deletions
diff --git a/drivers/avr/analog.c b/drivers/avr/analog.c
index 1a8da4261d..abe478b712 100644
--- a/drivers/avr/analog.c
+++ b/drivers/avr/analog.c
@@ -14,24 +14,31 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-// Simple analog to digitial conversion
-
#include <avr/io.h>
#include <avr/pgmspace.h>
#include <stdint.h>
#include "analog.h"
-static uint8_t aref = (1 << REFS0); // default to AREF = Vcc
+static uint8_t aref = ADC_REF_POWER;
-void analogReference(uint8_t mode) { aref = mode & 0xC0; }
+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__)
- static const uint8_t PROGMEM pin_to_mux[] = {0x00, 0x01, 0x04, 0x05, 0x06, 0x07, 0x25, 0x24, 0x23, 0x22, 0x21, 0x20};
+ // 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_AT90USB1286__)
+#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
@@ -39,20 +46,87 @@ int16_t analogRead(uint8_t pin) {
#endif
}
-// Mux input
+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) {
-#if defined(__AVR_AT90USB162__)
- 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!
+ // 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;
}
diff --git a/drivers/avr/analog.h b/drivers/avr/analog.h
index 1b773d82ce..058882450d 100644
--- a/drivers/avr/analog.h
+++ b/drivers/avr/analog.h
@@ -14,45 +14,40 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-#ifndef _analog_h_included__
-#define _analog_h_included__
+#pragma once
#include <stdint.h>
+#include "quantum.h"
#ifdef __cplusplus
extern "C" {
#endif
void analogReference(uint8_t mode);
int16_t analogRead(uint8_t pin);
+
+int16_t analogReadPin(pin_t pin);
+uint8_t pinToMux(pin_t pin);
+
int16_t adc_read(uint8_t mux);
#ifdef __cplusplus
}
#endif
-#define ADC_REF_POWER (1 << REFS0)
-#define ADC_REF_INTERNAL ((1 << REFS1) | (1 << REFS0))
-#define ADC_REF_EXTERNAL (0)
+#define ADC_REF_EXTERNAL 0 // AREF, Internal Vref turned off
+#define ADC_REF_POWER _BV(REFS0) // AVCC with external capacitor on AREF pin
+#define ADC_REF_INTERNAL (_BV(REFS1) | _BV(REFS0)) // Internal 2.56V Voltage Reference with external capacitor on AREF pin (1.1V for 328P)
// These prescaler values are for high speed mode, ADHSM = 1
-#if F_CPU == 16000000L
-# define ADC_PRESCALER ((1 << ADPS2) | (1 << ADPS1))
+#if F_CPU == 16000000L || F_CPU == 12000000L
+# define ADC_PRESCALER (_BV(ADPS2) | _BV(ADPS1)) // /64
#elif F_CPU == 8000000L
-# define ADC_PRESCALER ((1 << ADPS2) | (1 << ADPS0))
+# define ADC_PRESCALER (_BV(ADPS2) | _BV(ADPS0)) // /32
#elif F_CPU == 4000000L
-# define ADC_PRESCALER ((1 << ADPS2))
+# define ADC_PRESCALER (_BV(ADPS2)) // /16
#elif F_CPU == 2000000L
-# define ADC_PRESCALER ((1 << ADPS1) | (1 << ADPS0))
+# define ADC_PRESCALER (_BV(ADPS1) | _BV(ADPS0)) // /8
#elif F_CPU == 1000000L
-# define ADC_PRESCALER ((1 << ADPS1))
+# define ADC_PRESCALER _BV(ADPS1) // /4
#else
-# define ADC_PRESCALER ((1 << ADPS0))
-#endif
-
-// some avr-libc versions do not properly define ADHSM
-#if defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB1286__)
-# if !defined(ADHSM)
-# define ADHSM (7)
-# endif
-#endif
-
+# define ADC_PRESCALER _BV(ADPS0) // /2
#endif