hts221.hpp

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/* SPDX-License-Identifier: Apache-2.0 */
/* Copyright 2018-2019 Peter A. Bigot */
 
#ifndef NRFCXX_SENSOR_HTS221_HPP
#define NRFCXX_SENSOR_HTS221_HPP
#pragma once
 
#include <climits>
 
#include <nrfcxx/gpio.hpp>
#include <nrfcxx/lpm.hpp>
 
namespace nrfcxx {
namespace sensor {
 
class hts221 : public lpm::lpsm_capable
{
  using super = lpm::lpsm_capable;
public:
  struct iface_config_type
  {
    periph::TWI& twi;
 
    int8_t drdy_psel;
 
    uint8_t address;
 
    iface_config_type (const iface_config_type&) = delete;
    iface_config_type& operator= (const iface_config_type&) = delete;
    iface_config_type (iface_config_type&&) = delete;
    iface_config_type& operator= (iface_config_type&&) = delete;
  };
 
  const iface_config_type& iface_config () const
  {
    return iface_config_;
  }
 
  struct calibration_type
  {
    int16_t cal_cCel[2];
 
    uint16_t cal_pptt[2];
 
    int16_t td_cCel;
 
    int16_t hd_pptt;
 
    int16_t t0_out;
 
    int16_t h0_out;
 
    int16_t td_out;
 
    int16_t hd_out;
 
    int16_t conv_cCel (int16_t t_out) const
    {
      return cal_cCel[0] + td_cCel * (t_out - t0_out) / td_out;
    }
 
    uint16_t conv_pptt (int16_t h_out) const
    {
      return cal_pptt[0] + hd_pptt * (h_out - h0_out) / hd_out;
    }
  };
 
  const calibration_type& calibration () const
  {
    return calibration_;
  }
 
  enum STATUS_REG_e : uint8_t
  {
    SR_T_DA = 0x01,
 
    SR_H_DA = 0x02,
 
    SR_READY = (SR_T_DA | SR_H_DA),
  };
 
  int status () const;
 
  static constexpr uint16_t INVALID_OBSERVATION = 30000;
 
  struct observations_type
  {
    int16_t temperature_cCel{INVALID_OBSERVATION};
 
    uint16_t humidity_pptt{INVALID_OBSERVATION};
  };
 
  const observations_type& observations () const
  {
    return observations_;
  }
 
  enum ODR_e : uint8_t
  {
    ODR_OneShot = 0x00,
 
    ODR_1_Hz = 0x01,
 
    ODR_7_Hz = 0x02,
 
    ODR_12p5_Hz = 0x03,
  };
 
  static constexpr auto ODR_DEFAULT = ODR_1_Hz;
 
  uint8_t odr () const
  {
    return odr_;
  }
 
  int odr (uint8_t dr);
 
  hts221 (notifier_type notify,
          iface_config_type& ifc);
 
  bool drdy_asserted () const
  {
    return nrf5::GPIO->IN & (1U << iface_config_.drdy_psel);
  }
 
  int lpsm_sample () override;
 
  uint16_t lost_drdy () const
  {
    return lost_drdy_;
  }
 
private:
  int lpsm_process_ (int& delay,
                     process_flags_type& pf) override;
 
  void drdy_callback_ (const periph::GPIOTE::sense_status_type*);
 
  iface_config_type& iface_config_;
  calibration_type calibration_{};
  observations_type observations_{};
  periph::GPIOTE::sense_listener drdy_listener_;
  uint8_t odr_ = ODR_DEFAULT;
  uint16_t lost_drdy_ = 0;
};
 
} // ns sensor
} // ns nrfcxx
 
#endif /* NRFCXX_SENSOR_HTS221_HPP */