display_ly091wg14.h

/***************************************************************************
 *   Copyright (C) 2018 by Terraneo Federico                               *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
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 *   As a special exception, if other files instantiate templates or use   *
 *   macros or inline functions from this file, or you compile this file   *
 *   and link it with other works to produce a work based on this file,    *
 *   this file does not by itself cause the resulting work to be covered   *
 *   by the GNU General Public License. However the source code for this   *
 *   file must still be made available in accordance with the GNU General  *
 *   Public License. This exception does not invalidate any other reasons  *
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 *   Public License.                                                       *
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 ***************************************************************************/

#pragma once

#include "display_generic_1bpp.h"
#include <util/software_i2c.h>
#include <algorithm>

namespace mxgui {

/**
 * A small (0.91"), 128x32 pixel monochrome inexpensive and not particularly
 * fast (I2C interface) OLED display that can be easily found on ebay.
 * 
 * This driver uses software I2C
 * 
 * \tparam SDA I2C SDA Gpio connected to the display (requires 4k7 pullup)
 * \tparam SCL I2C SCL Gpio connected to the display (requires 4k7 pullup)
 * \tparam RESET RESET Gpio connected to the display
 */
template<typename SDA, typename SCL, typename RESET>
class DisplayLy091wg14 : public DisplayGeneric1BPP
{
public:
    /*
     * Constructor
     */
    DisplayLy091wg14();
        
    /**
     * Turn the display On after it has been turned Off.
     * Display initial state is On.
     */
    void doTurnOn() override { cmd(0xaf); }

    /**
     * Turn the display Off. It can be later turned back On.
     */
    void doTurnOff() override { cmd(0xae); }
    
    /**
     * Set display brightness. Depending on the underlying driver,
     * may do nothing.
     * \param brt from 0 to 100
     */
    void doSetBrightness(int brt) override
    {
        int brightness=std::max(0,std::min(255,5+brt*2+brt/2)); //5+brt*2.5
        cmd(0x81); cmd(brightness);
    }
    
    /**
     * Make all changes done to the display since the last call to update()
     * visible. Backends that require it may override this.
     */
    void update() override
    {
        //Takes ~21ms
        cmd(0x21); cmd(0); cmd(127);
        cmd(0x22); cmd(0); cmd(3);
        
        i2c::sendStart();
        if(i2c::send(ADDR)==0) { i2c::sendStop(); return; }
        i2c::send(GDATA);
        for(int i=0;i<fbSize;i++) i2c::send(backbuffer[i]);
        i2c::sendStop();
    }
    
private:
    using i2c=miosix::SoftwareI2C<SDA,SCL,0,true>;

    static const unsigned char ADDR    = 0b01111000;
    static const unsigned char COMMAND = 0b10000000;
    static const unsigned char GDATA   = 0b01000000;

    static void cmd(unsigned char c);
};

template<typename SDA, typename SCL, typename RESET>
DisplayLy091wg14<SDA,SCL,RESET>::DisplayLy091wg14() : DisplayGeneric1BPP(128,32)
{
    using namespace miosix;

    RESET::mode(Mode::OUTPUT);
    i2c::init();

    RESET::high();
    Thread::sleep(1);
    RESET::low();
    delayUs(100);
    RESET::high();
    delayUs(100);
    
    cmd(0xae);                         // Display off
    cmd(0xd5); cmd(0x80);              // Oscillator settings 0x8, divide by 1
    cmd(0xa8); cmd(height-1);          // Mux ratio
    cmd(0xd3); cmd(0x00);              // Display offset 0
    cmd(0x40);                         // Display start line 0
    cmd(0x8d); cmd(0x14);              // ?
    cmd(0x20); cmd(0x00);              // Memory addrressing horizontal
    cmd(0xa1);                         // Remap: col127=seg0
    cmd(0xc8);                         // COM scan direction decreasing
    cmd(0xda); cmd(0x02);              // COM sequential, not remapped
    cmd(0x81); cmd(0x80);              // Default brightness
    cmd(0xd9); cmd(0xf1);              // Precharge periods
    cmd(0xdb); cmd(0x40);              // VCOMH
    cmd(0xa6);                         // Normal display mode
    clear(0);
    update();
    cmd(0xaf);                         // Display on
    setTextColor(std::make_pair(Color(0xf),Color(0x0)));
}

template<typename SDA, typename SCL, typename RESET>
void DisplayLy091wg14<SDA,SCL,RESET>::cmd(unsigned char c)
{
    i2c::sendStart();
    if(i2c::send(ADDR)==0) { i2c::sendStop(); return; }
    i2c::send(COMMAND);
    i2c::send(c);
    i2c::sendStop();
}

} //namespace mxgui