grbl/adc.h

/*
  adc.h - Low level header for exposing ADC (Analog Digital Converter)
  functionalities
  Part of Grbl

  Copyright (c) 2019 Luigi Santivetti

  Grbl 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 3 of the License, or
  (at your option) any later version.

  Grbl 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 Grbl.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef adc_h
#define adc_h

#define ADC_CHANNEL_00_ENABLED ((DEFAULT_ADC_CHANNELS_MASK & bit(0)) >> 0)
#define ADC_CHANNEL_01_ENABLED ((DEFAULT_ADC_CHANNELS_MASK & bit(1)) >> 1)
#define ADC_CHANNEL_02_ENABLED ((DEFAULT_ADC_CHANNELS_MASK & bit(2)) >> 2)
#define ADC_CHANNEL_03_ENABLED ((DEFAULT_ADC_CHANNELS_MASK & bit(3)) >> 3)
#define ADC_CHANNEL_04_ENABLED ((DEFAULT_ADC_CHANNELS_MASK & bit(4)) >> 4)
#define ADC_CHANNEL_05_ENABLED ((DEFAULT_ADC_CHANNELS_MASK & bit(5)) >> 5)
#define ADC_CHANNEL_06_ENABLED ((DEFAULT_ADC_CHANNELS_MASK & bit(6)) >> 6)
#define ADC_CHANNEL_07_ENABLED ((DEFAULT_ADC_CHANNELS_MASK & bit(7)) >> 7)
#define ADC_CHANNEL_08_ENABLED ((DEFAULT_ADC_CHANNELS_MASK & bit(8)) >> 8)
#define ADC_CHANNEL_09_ENABLED ((DEFAULT_ADC_CHANNELS_MASK & bit(9)) >> 9)
#define ADC_CHANNEL_10_ENABLED ((DEFAULT_ADC_CHANNELS_MASK & bit(10)) >> 10)

#if DEFAULT_ADC_READINGS > 1
// ADC ISR callbacks
  #define ADC_ISR_PFN_SUM_ID 0
  #define ADC_ISR_PFN_AVR_ID 1
  #if DEFAULT_ADC_MODE == MODE0
    #define ADC_ISR_PFN_RST_ID 2
    #define ADC_ISR_APFN_COUNT 3
  #else
    #define ADC_ISR_APFN_COUNT 2
  #endif
#endif

// Number of enabled channels
#define ADC_CHANNELS_ENABLED_COUNT                                            \
  (ADC_CHANNEL_00_ENABLED + ADC_CHANNEL_01_ENABLED + ADC_CHANNEL_02_ENABLED + \
   ADC_CHANNEL_03_ENABLED + ADC_CHANNEL_04_ENABLED + ADC_CHANNEL_05_ENABLED + \
   ADC_CHANNEL_06_ENABLED + ADC_CHANNEL_07_ENABLED + ADC_CHANNEL_08_ENABLED + \
   ADC_CHANNEL_09_ENABLED + ADC_CHANNEL_10_ENABLED)

// Holding ADC readings
#if DEFAULT_ADC_RESOLUTION == 8
  typedef uint8_t adc_value;
#else
  typedef uint16_t adc_value;
#endif

typedef struct _adc_data adc_data;

#ifdef ADC_CONFIG_SYSTEM_ALARM
  #define ADC_INVALID_RANGE_CHANNEL(NUMBER)                                       \
    ((!defined(DEFAULT_ADC_RANGE_CHANNEL_ ## NUMBER ## _MIN) ||                   \
      !defined(DEFAULT_ADC_RANGE_CHANNEL_ ## NUMBER ## _MAX)) ||                  \
     ((DEFAULT_ADC_RANGE_CHANNEL_ ## NUMBER ## _MIN >> DEFAULT_ADC_RESOLUTION) || \
      (DEFAULT_ADC_RANGE_CHANNEL_ ## NUMBER ## _MAX >> DEFAULT_ADC_RESOLUTION)))

  #if ADC_CHANNEL_00_ENABLED && ADC_INVALID_RANGE_CHANNEL(0)
    #error "Invalid ADC00 range"
  #endif
  #if ADC_CHANNEL_01_ENABLED && ADC_INVALID_RANGE_CHANNEL(1)
    #error "Invalid ADC01 range"
  #endif
  #if ADC_CHANNEL_02_ENABLED && ADC_INVALID_RANGE_CHANNEL(2)
    #error "Invalid ADC02 range"
  #endif
  #if ADC_CHANNEL_03_ENABLED && ADC_INVALID_RANGE_CHANNEL(3)
    #error "Invalid ADC03 range"
  #endif
  #if ADC_CHANNEL_04_ENABLED && ADC_INVALID_RANGE_CHANNEL(4)
    #error "Invalid ADC04 range"
  #endif
  #if ADC_CHANNEL_05_ENABLED && ADC_INVALID_RANGE_CHANNEL(5)
    #error "Invalid ADC05 range"
  #endif
  #if ADC_CHANNEL_06_ENABLED && ADC_INVALID_RANGE_CHANNEL(6)
    #error "Invalid ADC06 range"
  #endif
  #if ADC_CHANNEL_07_ENABLED && ADC_INVALID_RANGE_CHANNEL(7)
    #error "Invalid ADC07 range"
  #endif
  #if ADC_CHANNEL_08_ENABLED && ADC_INVALID_RANGE_CHANNEL(8)
    #error "Invalid ADC08 range"
  #endif
  #if ADC_CHANNEL_09_ENABLED && ADC_INVALID_RANGE_CHANNEL(9)
    #error "Invalid ADC09 range"
  #endif
  #if ADC_CHANNEL_10_ENABLED && ADC_INVALID_RANGE_CHANNEL(10)
    #error "Invalid ADC10 range"
  #endif
#endif

typedef enum {
  #if ADC_CHANNEL_00_ENABLED
    ADC0,
  #endif
  #if ADC_CHANNEL_01_ENABLED
    ADC1,
  #endif
  #if ADC_CHANNEL_02_ENABLED
    ADC2,
  #endif
  #if ADC_CHANNEL_03_ENABLED
    ADC3,
  #endif
  #if ADC_CHANNEL_04_ENABLED
    ADC4,
  #endif
  #if ADC_CHANNEL_05_ENABLED
    ADC5,
  #endif
  #if ADC_CHANNEL_06_ENABLED
    ADC6,
  #endif
  #if ADC_CHANNEL_07_ENABLED
    ADC7,
  #endif
  #if ADC_CHANNEL_08_ENABLED
    ADC8, // Internal temperature
  #endif
  #if ADC_CHANNEL_09_ENABLED
    ADC9, // Minimum voltage
  #endif
  #if ADC_CHANNEL_10_ENABLED
    ADC10, // Bendgap voltage
  #endif
} adc_channel;

struct _adc_data {
  #if DEFAULT_ADC_READINGS > 1
    // Array of function pointers called back from the ADC ISR and void if-else
    void (* isr[ADC_ISR_APFN_COUNT])(adc_data *adc);

    // Store partial updates per channel
    uint16_t sum;

    // Index tracking the current number of reading
    uint8_t i_r;
  #endif

  // Index for the current channel to be stored in the buffer
  volatile adc_channel i_c;

  // Bitmask for the current status. The first 11 bit are reserved, where the
  // i-bit set to 1 flags the i-th channel is drained and the buffer holds
  // reliable data. The last 3 bits are for regular ADC ops signalling.
  volatile uint16_t s;

  // Buffer holding readings per channel
  struct {
    volatile adc_value avr;
    #ifdef ADC_CONFIG_SYSTEM_ALARM
      adc_value min;
      adc_value max;
    #endif
  } __attribute__ ((packed)) b[ADC_CHANNELS_ENABLED_COUNT];
} __attribute__ ((packed));

// Setup the ADC with DEFAULTS, enable it and kick a conversion
void adc_init(adc_data *adc);

// Teardown ADC, need to reinit afterwards
void adc_deinit(adc_data *adc);

// Read unsigned ADC buffer value for channel
adc_value adc_read_unsigned(const adc_data *adc, const adc_channel c);

#endif