ad7689.h

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#ifndef AD7689_H
#define AD7689_H

#if defined(ARDUINO) && ARDUINO >= 100
#include <Arduino.h>
#else
#include <WProgram.h>
#endif

#include "yspi.h"
#include "yADC.h"

// input configuration: bipolar/unipolar, single ended or differential
#define INCC_BIPOLAR_DIFF     (0b000) // 00X
#define INCC_BIPOLAR_COM      (0b010)
#define INCC_TEMP             (0b011)
#define INCC_UNIPOLAR_DIFF    (0b100)// 10X
#define INCC_UNIPOLAR_REF_COM (0b110)
#define INCC_UNIPOLAR_REF_GND (0b111)

// reference voltage (note: decoupling caps required on REF/REFIN when using INT_REF!)
#define INT_REF_25            (0b000)
#define INT_REF_4096          (0b001)
#define EXT_REF_TEMP_ON       (0b010)
#define EXT_REF_TEMP_BUF      (0b011)
#define EXT_REF_TEMP_OFF      (0b110)
#define EXT_REF_TEMP_OFF_BUF  (0b111)

// sequencer configuration (default: no sequencer)
#define SEQ_OFF               (0b00)
#define SEQ_UPDATE            (0b01)
#define SEQ_SCAN_INPUT_TEMP   (0b10)
#define SEQ_SCAN_INPUT        (0b11)

#define MAX_FREQ              (38000000) // 26 ns period @ VDD 5V and VIO 3.3 - 5V

#define UNIPOLAR_MODE         (0)
#define BIPOLAR_MODE          (1)
#define DIFFERENTIAL_MODE     (2)

#define REF_INTERNAL          (0)
#define REF_EXTERNAL          (1)
#define REF_GND               (2)
#define REF_COM               (3)

// bit shifts needed for config register values, from datasheet p. 27 table 11:
#define CFG                   (13)
#define INCC                  (10)
#define INx                   (7)
#define BW                    (6)
#define REF                   (3)
#define SEQ                   (1)
#define RB                    (0)

#define TEMP_REF              (4.096)  // reference voltage to be used for temperature measurement, either 2.5V or 4.096V
#define BASE_TEMP             (25)
#define TEMP_BASE_VOLTAGE     (0.283)
#define TEMP_RICO             (0.001)
#define INTERNAL_25           (2.5)
#define INTERNAL_4096         (4.096)
#define TOTAL_CHANNELS        (8)
#define TOTAL_STEPS           (65536)
#define TCONV                 (4)
#define TACQ                  (2)
#define STARTUP_DELAY         (100)

struct AD7689_conf {
  bool    CFG_conf;       
  uint8_t INCC_conf;      
  uint8_t INx_conf;       
  uint8_t BW_conf;        
  uint8_t REF_conf;       
  uint8_t SEQ_conf;       
  float   REF_voltage;    
  bool    RB_conf;        
};

class AD7689 : public YADC {
  protected:
    AD7689_conf conf;                       
    const float posref;                           
    const float negref;                           
    const uint8_t refsrc;                         
    const uint8_t inputConfig;                    
    const uint8_t refConfig;                      
    uint32_t timeStamps[TOTAL_CHANNELS];    
    uint16_t samples[TOTAL_CHANNELS];       
    uint16_t framePeriod;                   
    uint16_t curTemp;                       
    uint16_t tempTime;                      
    uint32_t lastSeqEndTime;                
    uint8_t  inputCount;                    
    bool sequencerActive;                   
    bool filterConfig;                      
    uint16_t    shiftTransaction(uint16_t command, bool readback, uint16_t* rb_cmd_ptr) const;
    uint16_t    toCommand(AD7689_conf cfg) const;
    AD7689_conf getADCConfig(bool default_config = false);
    float       readTemperature(void);
    void        configureSequencer();
    void        readChannels(uint8_t channels, uint8_t mode, uint16_t* data, uint16_t* temp);
    float       calculateVoltage(uint16_t sample) const;
    float      calculateTemp(uint16_t temp) const;
    uint32_t   initSampleTiming(void);
    void       cycleTimingBenchmark(void);
    
    // initialisation funcitons
    uint8_t getInputConfig(uint8_t polarity, bool differential) const;
    float   getNegRef(float posR, uint8_t polarity) const;
    uint8_t getRefSrc(uint8_t refS, float posR) const;
    float   getPosRef(uint8_t refS, float posR) const;
    
  public:
    AD7689(const YSPI *const y, uint8_t numberChannels = TOTAL_CHANNELS);
    void enableFiltering(bool onOff);
    float acquireChannel(uint8_t channel, uint32_t* timeStamp);
    float acquireChannel(uint8_t channel);
    float acquireTemperature();
    bool selftest(void);
};
#endif