File content as of revision 2:0e21d2f2155a:

/*
$Id:$

ST7565 LCD library!

Copyright (C) 2010 Limor Fried, Adafruit Industries

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library 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
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

// some of this code was written by <cstone@pobox.com> originally; it is in the public domain.


******the library is modified for mbed**********
    http://www.adafruit.com/products/250
    
    *!function drawbitmap(); is left undone!*
    
                    2014/03/18     by imachooon
                    mailto: imachooon@gmail.com
************************************************
*/

#include "st7565LCD.h"
#include "st7565LCDfont.h"

#define ST7567 //

#ifdef ST7567
#define ST7565_STARTBYTES 0 
const uint8_t pagemap[] = { 7, 6, 5, 4, 3, 2, 1, 0 };
#else
#define ST7565_STARTBYTES 1
const uint8_t pagemap[] = { 3, 2, 1, 0, 7, 6, 5, 4 };
#endif

uint8_t is_reversed = 0;

// a handy reference to where the pages are on the screen

// a 5x7 font table
extern const uint8_t font[];

// the memory buffer for the LCD
uint8_t st7565_buffer[1024] = {
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,

    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x3, 0x7, 0xF, 0x1F, 0x1F, 0x3F, 0x3F, 0x3F, 0x3F, 0x7, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x7F, 0x3F, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x1F, 0x3F, 0x70, 0x70, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x6, 0x6, 0x0, 0x0, 0x0, 0x3, 0x3,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,

    0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0x1F, 0xF, 0x7, 0x7,
    0x7, 0x3F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x3E, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xF, 0x3F,
    0x70, 0x60, 0x60, 0x60, 0x60, 0x30, 0x7F, 0x3F, 0x0, 0x0, 0x1F, 0x3F, 0x70, 0x60, 0x60, 0x60,
    0x60, 0x39, 0xFF, 0xFF, 0x0, 0x6, 0x1F, 0x39, 0x60, 0x60, 0x60, 0x60, 0x30, 0x3F, 0x7F, 0x0,
    0x0, 0x60, 0xFF, 0xFF, 0x60, 0x60, 0x0, 0x7F, 0x7F, 0x70, 0x60, 0x60, 0x40, 0x0, 0x7F, 0x7F,
    0x0, 0x0, 0x0, 0x0, 0x7F, 0x7F, 0x0, 0x0, 0x0, 0x7F, 0x7F, 0x0, 0x0, 0x60, 0xFF, 0xFF,
    0x60, 0x60, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,

    0x80, 0xF8, 0xFC, 0xFE, 0xFE, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xEF, 0xE7, 0xE7, 0xE3,
    0xF3, 0xF9, 0xFF, 0xFF, 0xFF, 0xF7, 0x7, 0x1F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x7F, 0xFF,
    0x7F, 0x7F, 0x7F, 0x7F, 0x7F, 0x7F, 0x3F, 0x3F, 0x1F, 0xF, 0x7, 0x3, 0x0, 0x0, 0x0, 0xC0,
    0xE0, 0x60, 0x20, 0x20, 0x60, 0xE0, 0xE0, 0xE0, 0x0, 0x0, 0x80, 0xC0, 0xE0, 0x60, 0x20, 0x60,
    0x60, 0xE0, 0xE0, 0xE0, 0x0, 0x0, 0x80, 0xC0, 0x60, 0x60, 0x20, 0x60, 0x60, 0xE0, 0xE0, 0x0,
    0x0, 0x0, 0xE0, 0xE0, 0x0, 0x0, 0x0, 0xE0, 0xE0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x80, 0xE0,
    0x60, 0x60, 0x60, 0x60, 0xE0, 0x80, 0x0, 0x0, 0x0, 0xE0, 0xE0, 0x0, 0x0, 0x0, 0xE0, 0xE0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,

    0x0, 0x0, 0x0, 0x3, 0x7, 0x1F, 0x9F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFD, 0xF1, 0xE3,
    0xE3, 0xCF, 0xFF, 0xFF, 0xFF, 0xFF, 0xF0, 0xFC, 0x7F, 0x3F, 0x3F, 0x3F, 0x3F, 0x7F, 0xFF, 0xFF,
    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xFC, 0xF0, 0xE0, 0x80, 0x0, 0x0, 0x0, 0xC,
    0x1C, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x7F, 0x7F, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x7, 0x7, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1C, 0xC, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,

    0x0, 0x7, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xFE, 0xFE, 0xFE, 0xFC, 0xF8,
    0xF8, 0xF0, 0xFE, 0xFF, 0xFF, 0xFF, 0x7F, 0x3F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x1F,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xFF,
    0xFF, 0x0, 0x0, 0x0, 0xFF, 0xFF, 0xE0, 0xC0, 0xC0, 0xC0, 0xFF, 0x7F, 0x0, 0x0, 0x1E, 0x7F,
    0xE1, 0xC0, 0xC0, 0xC0, 0xC0, 0x61, 0xFF, 0xFF, 0x0, 0x0, 0xFE, 0xFF, 0x1, 0x0, 0x0, 0x0,
    0xFF, 0xFF, 0x0, 0x0, 0x21, 0xF9, 0xF8, 0xDC, 0xCC, 0xCF, 0x7, 0x0, 0xC0, 0xFF, 0xFF, 0xC0,
    0x80, 0x0, 0xFF, 0xFF, 0xC0, 0xC0, 0x80, 0x0, 0x0, 0xFF, 0xFF, 0x0, 0x0, 0x1F, 0x7F, 0xF9,
    0xC8, 0xC8, 0xC8, 0xC8, 0x79, 0x39, 0x0, 0x0, 0x71, 0xF9, 0xD8, 0xCC, 0xCE, 0x47, 0x3, 0x0,

    0x0, 0x0, 0x0, 0x0, 0x80, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x80, 0xC0, 0xE0, 0xF0, 0xF8, 0xF8, 0xFC, 0xFC, 0xFC, 0xFC, 0xF8, 0xF0, 0xC0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xC0,
    0xC0, 0x0, 0x0, 0x0, 0xC0, 0xC0, 0x0, 0x0, 0x0, 0x0, 0xC0, 0xC0, 0x0, 0x0, 0x0, 0x80,
    0xC0, 0xC0, 0xC0, 0xC0, 0xC0, 0x80, 0xC0, 0xC0, 0x0, 0x0, 0x0, 0x80, 0xC0, 0xC0, 0xC0, 0xC0,
    0xC0, 0x80, 0x0, 0x0, 0x80, 0xC0, 0xC0, 0xC0, 0xC0, 0xC0, 0x0, 0x0, 0x0, 0xC0, 0xC0, 0x0,
    0x0, 0x0, 0xC0, 0x80, 0x0, 0x0, 0x0, 0x0, 0x0, 0xC0, 0xC0, 0x0, 0x0, 0x0, 0x80, 0xC0,
    0xC0, 0xC0, 0xC0, 0xC0, 0x80, 0x80, 0x0, 0x0, 0x80, 0xC0, 0xC0, 0xC0, 0xC0, 0x80, 0x0, 0x0,

    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
};




// reduces how much is refreshed, which speeds it up!
// originally derived from Steve Evans/JCW's mod but cleaned up and
// optimized
#define enablePartialUpdate

#ifdef enablePartialUpdate
static uint8_t xUpdateMin, xUpdateMax, yUpdateMin, yUpdateMax;
#endif



static void updateBoundingBox(uint8_t xmin, uint8_t ymin, uint8_t xmax, uint8_t ymax)
{
#ifdef enablePartialUpdate
    if (xmin < xUpdateMin) xUpdateMin = xmin;
    if (xmax > xUpdateMax) xUpdateMax = xmax;
    if (ymin < yUpdateMin) yUpdateMin = ymin;
    if (ymax > yUpdateMax) yUpdateMax = ymax;
#endif
}

/*
void ST7565::drawbitmap(uint8_t x, uint8_t y,
            const uint8_t *bitmap, uint8_t w, uint8_t h,
            uint8_t color) {
  for (uint8_t i=0; i<h; i++) {
    for (uint8_t j=0; j<w; j++ ) {
      if (pgm_read_byte(bitmap + j + (j/8)*w) & _BV(j%8)) {
    my_setpixel(x+j, y+i, color);
      }
    }
  }

  updateBoundingBox(x, y, x+w, y+h);
}
*/

void ST7565::drawstring(uint8_t x, uint8_t line, char *c)
{
    while (*c != '\0') {
        drawchar(x, line, *c);
        *c++;
        x += 6; // 6 pixels wide
        if (x + 6 >= LCDWIDTH) {
            x = 0;    // ran out of this line
            line++;
        }
        if (line >= (LCDHEIGHT/8))
            return;        // ran out of space :(
    }
}


void  ST7565::drawchar(uint8_t x, uint8_t line, char c)
{
    for (uint8_t i =0; i<5; i++ ) {
        *(st7565_buffer + x + line*128) = *(font + (c*5) + i);
        x++;
    }
    updateBoundingBox(x, line*8, x+5, line*8+8);    //only updates relevant area of LCD
}


// bresenham's algorithm - thx wikpedia
void ST7565::drawline(uint8_t x0, uint8_t y0, uint8_t x1, uint8_t y1,
                      uint8_t color)
{
    uint8_t steep = abs(y1 - y0) > abs(x1 - x0);
    if (steep) {
        swap(x0, y0);
        swap(x1, y1);
    }

    if (x0 > x1) {
        swap(x0, x1);
        swap(y0, y1);
    }

    // much faster to put the test here, since we've already sorted the points
    updateBoundingBox(x0, y0, x1, y1);

    uint8_t dx, dy;
    dx = x1 - x0;
    dy = abs(y1 - y0);

    int8_t err = dx / 2;
    int8_t ystep;

    if (y0 < y1) {
        ystep = 1;
    } else {
        ystep = -1;
    }

    for (; x0<=x1; x0++) {
        if (steep) {
            my_setpixel(y0, x0, color);
        } else {
            my_setpixel(x0, y0, color);
        }
        err -= dy;
        if (err < 0) {
            y0 += ystep;
            err += dx;
        }
    }
}

// filled rectangle
void ST7565::fillrect(uint8_t x, uint8_t y, uint8_t w, uint8_t h,
                      uint8_t color)
{

    // stupidest version - just pixels - but fast with internal buffer!
    for (uint8_t i=x; i<x+w; i++) {
        for (uint8_t j=y; j<y+h; j++) {
            my_setpixel(i, j, color);
        }
    }

    updateBoundingBox(x, y, x+w, y+h);
}

// draw a rectangle
void ST7565::drawrect(uint8_t x, uint8_t y, uint8_t w, uint8_t h,
                      uint8_t color)
{
    // stupidest version - just pixels - but fast with internal buffer!
    for (uint8_t i=x; i<x+w; i++) {
        my_setpixel(i, y, color);
        my_setpixel(i, y+h-1, color);
    }
    for (uint8_t i=y; i<y+h; i++) {
        my_setpixel(x, i, color);
        my_setpixel(x+w-1, i, color);
    }

    updateBoundingBox(x, y, x+w, y+h);
}

// draw a circle outline
void ST7565::drawcircle(uint8_t x0, uint8_t y0, uint8_t r,
                        uint8_t color)
{
    updateBoundingBox(x0-r, y0-r, x0+r, y0+r);

    int8_t f = 1 - r;
    int8_t ddF_x = 1;
    int8_t ddF_y = -2 * r;
    int8_t x = 0;
    int8_t y = r;

    my_setpixel(x0, y0+r, color);
    my_setpixel(x0, y0-r, color);
    my_setpixel(x0+r, y0, color);
    my_setpixel(x0-r, y0, color);

    while (x<y) {
        if (f >= 0) {
            y--;
            ddF_y += 2;
            f += ddF_y;
        }
        x++;
        ddF_x += 2;
        f += ddF_x;

        my_setpixel(x0 + x, y0 + y, color);
        my_setpixel(x0 - x, y0 + y, color);
        my_setpixel(x0 + x, y0 - y, color);
        my_setpixel(x0 - x, y0 - y, color);

        my_setpixel(x0 + y, y0 + x, color);
        my_setpixel(x0 - y, y0 + x, color);
        my_setpixel(x0 + y, y0 - x, color);
        my_setpixel(x0 - y, y0 - x, color);

    }
}

void ST7565::fillcircle(uint8_t x0, uint8_t y0, uint8_t r,
                        uint8_t color)
{
    updateBoundingBox(x0-r, y0-r, x0+r, y0+r);

    int8_t f = 1 - r;
    int8_t ddF_x = 1;
    int8_t ddF_y = -2 * r;
    int8_t x = 0;
    int8_t y = r;

    for (uint8_t i=y0-r; i<=y0+r; i++) {
        my_setpixel(x0, i, color);
    }

    while (x<y) {
        if (f >= 0) {
            y--;
            ddF_y += 2;
            f += ddF_y;
        }
        x++;
        ddF_x += 2;
        f += ddF_x;

        for (uint8_t i=y0-y; i<=y0+y; i++) {
            my_setpixel(x0+x, i, color);
            my_setpixel(x0-x, i, color);
        }
        for (uint8_t i=y0-x; i<=y0+x; i++) {
            my_setpixel(x0+y, i, color);
            my_setpixel(x0-y, i, color);
        }
    }
}

void ST7565::my_setpixel(uint8_t x, uint8_t y, uint8_t color)
{
    if ((x >= LCDWIDTH) || (y >= LCDHEIGHT))
        return;

    // x is which column
    if (color)
        st7565_buffer[x+ (y/8)*128] |= _BV(7-(y%8));
    else
        st7565_buffer[x+ (y/8)*128] &= _nBV(7-(y%8));
}

// the most basic function, set a single pixel
void ST7565::setpixel(uint8_t x, uint8_t y, uint8_t color)
{
    if ((x >= LCDWIDTH) || (y >= LCDHEIGHT))
        return;
    // x is which column
    if (color)
        st7565_buffer[x+ (y/8)*128] |= _BV(7-(y%8));
    else
        st7565_buffer[x+ (y/8)*128] &= _nBV(7-(y%8));

    updateBoundingBox(x,y,x,y);
}


// the most basic function, get a single pixel
uint8_t ST7565::getpixel(uint8_t x, uint8_t y)
{
    if ((x >= LCDWIDTH) || (y >= LCDHEIGHT))
        return 0;

    return (st7565_buffer[x+ (y/8)*128] >> (7-(y%8))) & 0x1;
}


ST7565::ST7565(PinName mosi, PinName sclk, PinName cs, PinName rst, PinName a0)
// set pin directions
    : _spi(mosi, NC, sclk), _cs(cs), _rst(rst), _a0(a0)

{
    _spi.format(8, 0);
    _spi.frequency(1000000);
}

void ST7565::set_spi_frequency(int frequency)
{
    _spi.frequency(frequency);
}

void ST7565::st7565_init(void)
{
    wait_ms(100); 
    _rst = 0;
    wait_ms(100);
    _rst = 1;
    

    // LCD bias select
    st7565_command(CMD_SET_BIAS_7);
    // ADC select
    st7565_command(CMD_SET_ADC_NORMAL);
    // SHL select
    st7565_command(CMD_SET_COM_NORMAL);

    // turn on voltage converter (VC=1, VR=0, VF=0)
    st7565_command(CMD_SET_POWER_CONTROL | 0x4);
    // wait for 50% rising
    wait_ms(50);

    // turn on voltage regulator (VC=1, VR=1, VF=0)
    st7565_command(CMD_SET_POWER_CONTROL | 0x6);
    // wait >=50ms
    wait_ms(20);

    // turn on voltage follower (VC=1, VR=1, VF=1)
    st7565_command(CMD_SET_POWER_CONTROL | 0x7);
    // wait
    wait_ms(10);
    
    // set lcd operating voltage (regulator resistor, ref voltage resistor)
    st7565_command(CMD_SET_RESISTOR_RATIO | 0x4);
    wait_ms(10);


//    st7565_set_brightness(INITIAL_CONTRAST);
    // set up a bounding box for screen updates
    updateBoundingBox(0, 0, LCDWIDTH-1, LCDHEIGHT-1);


    st7565_command(CMD_DISPLAY_ON);
    st7565_command(CMD_SET_ALLPTS_NORMAL);
    
    
    // reference voltage resistor    
    st7565_command(CMD_SET_VOLUME_FIRST);
    wait_ms(10);
    st7565_command(CMD_SET_VOLUME_SECOND);
    wait_ms(10);



    // Initial display line ( = 0)
    st7565_command(CMD_SET_DISP_START_LINE);
    // Initial page address ( = 0)
    st7565_command(CMD_SET_PAGE);    
    st7565_command(CMD_SET_COLUMN_UPPER);
    st7565_command(CMD_SET_COLUMN_LOWER);
    
}

inline void ST7565::spiwrite(uint8_t c)
{
    _spi.write(c);
}

void ST7565::st7565_command(uint8_t c)
{
    _cs = 0;
    _a0 = 0;
    _spi.write(c);
    _cs = 1;
}

void ST7565::st7565_data(uint8_t c)
{
    _cs = 0;
    _a0 = 1;
    _spi.write(c);
    _cs = 1;
}

void ST7565::st7565_set_brightness(uint8_t val)
{
    st7565_command(CMD_SET_VOLUME_FIRST);
    st7565_command(CMD_SET_VOLUME_SECOND | (val & 0x3f));
}

void ST7565::begin(uint8_t contrast){
    st7565_init();
  st7565_command(CMD_DISPLAY_ON);
  st7565_command(CMD_SET_ALLPTS_NORMAL);
  st7565_set_brightness(contrast);
}
    

void ST7565::display(void)
{
    uint8_t col, maxcol, p;

    for(p = 0; p < 8; p++) {
#ifdef enablePartialUpdate
        // check if this page is part of update
        if ( yUpdateMin >= ((p+1)*8) ) {
            continue;   // nope, skip it!
        }
        if (yUpdateMax < p*8) {
            break;
        }
#endif
        st7565_command(CMD_SET_PAGE | pagemap[p]);

#ifdef enablePartialUpdate
        col = xUpdateMin;
        maxcol = xUpdateMax;
#else
        // start at the beginning of the row
        col = 0;
        maxcol = LCDWIDTH-1;
#endif

        st7565_command(CMD_SET_COLUMN_LOWER | ((col+ST7565_STARTBYTES) & 0xf));
        st7565_command(CMD_SET_COLUMN_UPPER | (((col+ST7565_STARTBYTES) >> 4) & 0x0F));
        st7565_command(CMD_RMW);

        for(; col <= maxcol; col++) {
            st7565_data(st7565_buffer[(128*p)+col]);
        }
    }

#ifdef enablePartialUpdate
    xUpdateMin = LCDWIDTH - 1;
    xUpdateMax = 0;
    yUpdateMin = LCDHEIGHT-1;
    yUpdateMax = 0;
#endif
}

// clear everything
void ST7565::clear(void)
{
    memset(st7565_buffer, 0, 1024);
    updateBoundingBox(0, 0, LCDWIDTH-1, LCDHEIGHT-1);
}


// this doesnt touch the buffer, just clears the display RAM - might be handy
void ST7565::clear_display(void)
{
    uint8_t p, c;

    for(p = 0; p < 8; p++) {

        st7565_command(CMD_SET_PAGE | p);
        for(c = 0; c < 129; c++) {
            st7565_command(CMD_SET_COLUMN_LOWER | (c & 0xf));
            st7565_command(CMD_SET_COLUMN_UPPER | ((c >> 4) & 0xf));
            st7565_data(0x0);
        }
    }
}

//additional function to set a bit
uint8_t ST7565::_BV(uint8_t bit)
{
    return 1 << bit;
}

uint8_t ST7565::_nBV(uint8_t bit)
{
    return 0 << bit;
}