74LVC138AD.tpl.hpp

Go to the documentation of this file.

// Copyright (c) 2024 anabrid GmbH
// Contact: https://www.anabrid.com/licensing/
// SPDX-License-Identifier: MIT OR GPL-2.0-or-later
 
#pragma once
 
#include "bus/bus.h"
#include "metadata/metadata.h"
 
class MetadataMemory74LVC138AD : public metadata::MetadataMemory<256> {
public:
  static const SPISettings DEFAULT_SPI_SETTINGS;
 
  explicit MetadataMemory74LVC138AD(bus::addr_t address)
      : metadata::MetadataMemory<256>(address, SPISettings(4'000'000, MSBFIRST, SPI_MODE0)) {}
 
  using MetadataMemory<256>::read_from_hardware;
 
  size_t read_from_hardware(size_t byte_offset, size_t length, uint8_t *buffer) const override {
    // Begin SPI communication
    begin_communication();
 
    // Send READ command B00000011
    bus::spi.transfer(0x3);
    // Send byte offset
    bus::spi.transfer(byte_offset);
    // Read data
    bus::spi.transfer(nullptr, buffer, length);
 
    // Release address and stop SPI transaction
    end_communication();
 
    return length;
  }
};
 
const SPISettings MetadataMemory74LVC138AD::DEFAULT_SPI_SETTINGS{4'000'000, MSBFIRST, SPI_MODE0};