EEPROM_93C46.hh

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#ifndef EEPROM_93C46_HH
#define EEPROM_93C46_HH
 
#include "EmuTime.hh"
#include "SRAM.hh"
 
#include <climits>
#include <string>
 
namespace openmsx {
 
class DeviceConfig;
class XMLElement;
 
class EEPROM_93C46
{
public:
        static constexpr uint8_t ADDRESS_BITS = 7;
        static constexpr uint32_t NUM_ADDRESSES = 1 << ADDRESS_BITS;
        static constexpr uint32_t ADDRESS_MASK = NUM_ADDRESSES - 1;
        static constexpr uint8_t DATA_BITS = 8; // only 8-bit mode implemented
 
public:
        explicit EEPROM_93C46(const XMLElement& xml); // unittest
        EEPROM_93C46(const std::string& name, const DeviceConfig& config);
 
        void reset();
 
        [[nodiscard]] bool read_DO(EmuTime::param time) const;
        void write_CS (bool value, EmuTime::param time);
        void write_CLK(bool value, EmuTime::param time);
        void write_DI (bool value, EmuTime::param time);
 
        template<typename Archive>
        void serialize(Archive& ar, unsigned version);
 
        // for unittest
        [[nodiscard]] const uint8_t* backdoor() const {
                return &sram[0];
        }
 
private:
        [[nodiscard]] uint8_t read(unsigned addr) const;
        void write(unsigned addr, uint8_t value, EmuTime::param time);
        void writeAll(uint8_t value, EmuTime::param time);
        void erase(unsigned addr, EmuTime::param time);
        void eraseAll(EmuTime::param time);
 
        [[nodiscard]] bool ready(EmuTime::param time) const;
        void clockEvent(EmuTime::param time);
        void execute_command(EmuTime::param time);
 
public: // for serialize
        enum class State {
                IN_RESET,
                WAIT_FOR_START_BIT,
                WAIT_FOR_COMMAND,
                READING_DATA,
                WAIT_FOR_WRITE,
                WAIT_FOR_WRITE_ALL,
        };
 
private:
        SRAM sram;
        EmuTime completionTime = EmuTime::zero();
        EmuTime csTime = EmuTime::zero();
        State state = State::IN_RESET;
        uint16_t shiftRegister = 0;
        uint8_t bits = 0;
        uint8_t address = 0;
        bool pinCS  = false;
        bool pinCLK = false;
        bool pinDI = false;
        bool writeProtected = true;
 
        static constexpr int SHIFT_REG_BITS = sizeof(shiftRegister) * CHAR_BIT;
};
 
} // namespace openmsx
 
#endif