functions.h

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// Copyright (c) 2024 anabrid GmbH
// Contact: https://www.anabrid.com/licensing/
// SPDX-License-Identifier: MIT OR GPL-2.0-or-later
 
#pragma once
 
#include <array>
#include <cstdint>
 
#include "teensy/bus.h"
 
namespace functions {
 
class Function {
public:
  const bus::addr_t address;
 
  // explicit keyword shall most certainly avoid accidental downcasting
  explicit Function(bus::addr_t address);
};
 
class TriggerFunction : public Function {
public:
  void trigger() const;
 
  using Function::Function;
};
 
class DataFunction : public Function {
protected:
  static SPIClass &get_raw_spi();
 
public:
  const SPISettings &spi_settings;
 
  /*
   * Constructor for a new DataFunction.
   * CARE: In my goal to optimize resource usage,
   *       I did not want each instance of DataFunction to hold onto its own SPISettings object,
   *       as e.g. all N ~= 100 coefficients use the same.
   *       Instead, a reference to e.g. a static member variable of the subclass should be passed.
   *       If the constructor is called like DataFunction(address, SPISettings(...)),
   *       the reference to the cleaned-up SPISettings object will be invalid and things will break.
   */
  DataFunction(bus::addr_t address, const SPISettings &spiSettings);
 
  void begin_communication() const;
  void end_communication() const;
 
protected:
  void transfer(const void *mosi_buf, void *miso_buf, size_t count) const;
  uint8_t transfer8(uint8_t data_in) const;
  uint16_t transfer16(uint16_t data_in) const;
  uint32_t transfer32(uint32_t data_in) const;
};
 
class SyncFunction : public DataFunction {
public:
  using DataFunction::DataFunction;
  using DataFunction::transfer16;
};
 
} // namespace functions