ST7920.hpp

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/*
 * This file is part of the DUDS project. It is subject to the BSD-style
 * license terms in the LICENSE file found in the top-level directory of this
 * distribution and at https://github.com/jjackowski/duds/blob/master/LICENSE.
 * No part of DUDS, including this file, may be copied, modified, propagated,
 * or distributed except according to the terms contained in the LICENSE file.
 *
 * Copyright (C) 2018  Jeff Jackowski
 */
#include <duds/hardware/interface/DigitalPinSet.hpp>
#include <duds/hardware/interface/ChipSelect.hpp>
#include <duds/hardware/display/BppGraphicDisplay.hpp>
#include <chrono>

namespace duds { namespace hardware { namespace devices { namespace displays {

class ST7920 : public duds::hardware::display::BppGraphicDisplay {
    duds::hardware::interface::DigitalPinSet outputs;
    duds::hardware::interface::ChipSelect enable;
    std::vector<duds::hardware::interface::DigitalPinConfig> outcfg;
    std::chrono::high_resolution_clock::time_point soonestSend;
    std::chrono::nanoseconds nibblePeriod;
    enum {
        dataMask   = 0xFF,
        textFlag   = 0x100,
        writeFlag  = 0x200,  // not presently supported; wire to ground
        nibbleFlag = 0x400
    };
    void wait() const;
    struct Access {
        duds::hardware::interface::DigitalPinSetAccess output;
        duds::hardware::interface::ChipAccess enable;
    };
    void preparePins(Access &acc);
    void sendByte(Access &acc, int val);
    void writeBlock(
        ST7920::Access &acc,
        const std::uint16_t *start,
        const std::uint16_t *end,
        int pos
    );
    virtual void outputFrame(const duds::ui::graphics::BppImage *img);
public:
    ST7920();
    ST7920(
        duds::hardware::interface::DigitalPinSet &&outPins,
        duds::hardware::interface::ChipSelect &&enablePin,
        unsigned int w,
        unsigned int h,
        std::chrono::nanoseconds delay = std::chrono::nanoseconds(8000)
    );
    virtual ~ST7920();
    void configure(
        duds::hardware::interface::DigitalPinSet &&outPins,
        duds::hardware::interface::ChipSelect &&enablePin,
        unsigned int w,
        unsigned int h,
        std::chrono::nanoseconds delay = std::chrono::nanoseconds(8000)
    );
    void initialize();
    void off();
    void on();
};

} } } }