Peter Drescher / C12832_lcd

Lib for the LCD display on mbed lab Board

Dependents:   SprintUSBModemWebsocketTest-LCD-RO iOSAppChat Christmas-LCD led_dimm ... more

Basic information

The LCD on the mbed lab board has 128 x 32 pixels and is connected via spi. It use a ST7565R controller. The spi connection is fast, but it has one drawback - you can't read the display buffer. This is a problem, because each bit reflect a pixel. If you want to set only one bit / pixel, you have to know the status of the other seven bits / pixel. Because of this we have to use a framebuffer (128 * 32 / 8 = 512 Byte). All drawing functions are working on this framebuffer. If you use the LPC1768 based mbed, the dma channel 0 is used to speed up the transfer to the lcd. This information is only relevant if you also want to use the dma controller. You have to switch to a other channel.

There are two update mode. After startup the automode is turned on. This means that the display is automaticly updated after the drawing. For example - if you call the function 

lcd.line(x0, y0, x1, y1, 1);

a line from x0,y0 to x1,y1 is drawn inside the framebuffer and after that the framebuffer is copied to the lcd. If you draw more lines, it will be faster to draw all graphics inside the framebuffer and update the lcd only once. To do so, you can use the function : 

lcd.set_auto_up(0);

This switch off the autoupdate. If you want to see it, you have to refresh the lcd by calling the function : 

lcd.copy_to_lcd();


lcd.set_auto_up(1);

will switch back to auto update mode.

Basic functions

To use the lcd we have to create a lcd object :

C12832_LCD lcd;

There are two drawing modes : NORMAL and XOR. At startup the mode is NORMAL. If you use 

lcd.setmode(XOR);

you switch to XOR mode. In this mode a pixel in the frambuffer is inverted if you set it to 1. 

lcd.setmode(NORMAL);

switch back to normal mode.

The function : 

lcd.invert(1);

will invert the lcd. This is done by the lcd controller. The framebuffer is not changed.

lcd.invert(0);

will switch back.

The function :

lcd.cls();

clear the screen.

The function :

lcd.set_contrast(25);

will set the contrast. The lib start with 23. A value between 10 and 35 will be visible.

Text

To print text you simply have to use the printf function. The output of the stdout is redirected to the lcd.

lcd.printf("temperature : %3.2f F",heat);

The position can be set up with the function :

lcd.locate(x,y);

At startup a 7 pixel font is used. If you want to use a different font you can include the lib http://mbed.org/users/dreschpe/code/LCD_fonts. This lib include four additional fonts. From 6 pixel to 23 pixel. To switch the font use :

lcd.set_font((unsigned char*) Arial_9);

The names of the fonts are : Small_6, Small_7, Arial_9, Arial12x12 and Arial24x23.

The function :

lcd._putc(c);

print the char c on the actual cursor position.

The function :

lcd.character(x, y, c);

print the char c at position x,y.

Graphic

The function :

lcd.line(x0, y0, x1, y1, color);

draw a single pixel line from x0,y0 to x1,y1. If color is 1 : black, 0 : white.

The function :

lcd.rect(x0, y0, x1, y1, color);

draw a single pixel rectangle from x0, y0 to x1, y1. If color is 1 : black, 0 : white.

The function :

lcd.fillrect(x0, y0, x1, y1, color);

draw a filled rectangle from x0, y0 to x1, y1. If color is 1 : black, 0 : white.

The function :

lcd.circle(x, y, r, color);

draw a circle with x,y center and radius r. If color is 1 : black, 0 : white.

The function :

lcd.fillcircle(x, y, r, color);

draw a filled circle with x,y center and radius r. If color is 1 : black, 0 : white.

The function :

lcd.pixel(x, y, color);

set a single pixel at x,y. If color is 1 : black, 0 : white. This function is not updating the lcd ! Even if the autoupdate is on. You have to call lcd.copy_to_lcd() after using this function - or to use a other function with autoupdate afterwards.

mbed rtos

To use the mbed rtos with the lib we have to make the lib thread save. What is the problem ? If different threads are writing to the lcd it can end in troubble. Thread1 is using the pintf("hello mbed") function to print this string to the actual position. After the chars "hel" are printed ,the scheduler is switching to thread2. This thread is writing at a different position on the screen. After that the scheduler is switch back to thread1 and the print function continue. Thread1 did not know that the internal cursor position has changed ....

To protect the access to the lcd we use a Mutex. If a thread has the mutex and a other thread also want it, the second thread has to wait. 

Mutex lcd_mutex;  // define the mutex
    //...
lcd_mutex.lock(); // get the mutex or wait

//acccess to the lcd
 
lcd_mutex.unlock(); // free the mutex

We use this framing to access the lcd.

Test program to show : http://mbed.org/users/dreschpe/code/lab1/

C12832_lcd.cpp

Committer:
sam_grove
Date:
2013-10-27
Revision:
10:8f86576007d6
Parent:
8:c9afe58d786a

File content as of revision 10:8f86576007d6:

/* mbed library for the mbed Lab Board  128*32 pixel LCD
 * use C12832 controller
 * Copyright (c) 2012 Peter Drescher - DC2PD
 * Released under the MIT License: http://mbed.org/license/mit
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

// 13.10.12    initial design
// 25.10.12    add autorefresh of screen
// 25.10.12    add standart font
// 20.12.12    add bitmap graphics

// optional defines :
// #define debug_lcd  1

#include "C12832_lcd.h"
#include "mbed.h"
#include "stdio.h"
#include "Small_7.h"

#define BPP    1       // Bits per pixel

C12832_LCD::C12832_LCD(const char* name)
    : _spi(p5,NC,p7),_reset(p6),_A0(p8),_CS(p11),GraphicsDisplay(name)
{
    orientation = 1;
    draw_mode = NORMAL;
    char_x = 0;
    lcd_reset();
}

int C12832_LCD::width()
{
    if (orientation == 0 || orientation == 2) return 32;
    else return 128;
}

int C12832_LCD::height()
{
    if (orientation == 0 || orientation == 2) return 128;
    else return 32;
}


/*void C12832_LCD::set_orientation(unsigned int o)
{
    orientation = o;
    switch (o) {
        case (0):
            wr_cmd(0xA0);
            wr_cmd(0xC0);
            break;
        case (1):
            wr_cmd(0xA0);
            wr_cmd(0xC8);
            break;
        case (2):
            wr_cmd(0xA1);
            wr_cmd(0xC8);
            break;
        case (3):
            wr_cmd(0xA1);
            wr_cmd(0xC0);
            break;
    }
}

*/

void C12832_LCD::invert(unsigned int o)
{
    if(o == 0) wr_cmd(0xA6);
    else wr_cmd(0xA7);
}


void C12832_LCD::set_contrast(unsigned int o)
{
    contrast = o;
    wr_cmd(0x81);      //  set volume
    wr_cmd(o & 0x3F);
}

unsigned int C12832_LCD::get_contrast(void)
{
    return(contrast);
}


// write command to lcd controller

void C12832_LCD::wr_cmd(unsigned char cmd)
{
    _A0 = 0;
    _CS = 0;
#if defined TARGET_LPC1768     // fast without mbed lib
    LPC_SSP1->DR = cmd;
    do {
    } while ((LPC_SSP1->SR & 0x10) == 0x10); // wait for SPI1 idle
#else
    _spi.write(cmd);
#endif
    _CS = 1;
}

// write data to lcd controller

void C12832_LCD::wr_dat(unsigned char dat)
{
    _A0 = 1;
    _CS = 0;
#if defined TARGET_LPC1768     // fast without mbed lib
    LPC_SSP1->DR = dat;
    do {
    } while ((LPC_SSP1->SR & 0x10) == 0x10); // wait for SPI1 idle
#else
    _spi.write(dat);
#endif
    _CS = 1;
}

// reset and init the lcd controller

void C12832_LCD::lcd_reset()
{

    _spi.format(8,3);                 // 8 bit spi mode 3
    _spi.frequency(20000000);          // 19,2 Mhz SPI clock
    DigitalOut _reset(p6);
    _A0 = 0;
    _CS = 1;
    _reset = 0;                        // display reset
    wait_us(50);
    _reset = 1;                       // end reset
    wait_ms(5);

    /* Start Initial Sequence ----------------------------------------------------*/

    wr_cmd(0xAE);   //  display off
    wr_cmd(0xA2);   //  bias voltage

    wr_cmd(0xA0);
    wr_cmd(0xC8);   //  colum normal

    wr_cmd(0x22);   //  voltage resistor ratio
    wr_cmd(0x2F);   //  power on
    //wr_cmd(0xA4);   //  LCD display ram
    wr_cmd(0x40);   // start line = 0
    wr_cmd(0xAF);     // display ON

    wr_cmd(0x81);   //  set contrast
    wr_cmd(0x17);   //  set contrast

    wr_cmd(0xA6);     // display normal


#if defined TARGET_LPC1768          //setup DMA channel 0       
    LPC_SC->PCONP |= (1UL << 29);   // Power up the GPDMA
    LPC_GPDMA->DMACConfig = 1;      // enable DMA controller
    LPC_GPDMA->DMACIntTCClear = 0x1;
    LPC_GPDMA->DMACIntErrClr = 0x1;
    LPC_GPDMACH0->DMACCLLI = 0;
#endif
    // clear and update LCD
    memset(buffer,0x00,512);  // clear display buffer
    copy_to_lcd();
    auto_up = 1;              // switch on auto update
    // dont do this by default. Make the user call
    //claim(stdout);           // redirekt printf to lcd
    locate(0,0);
    set_font((unsigned char*)Small_7);  // standart font
}

// set one pixel in buffer

void C12832_LCD::pixel(int x, int y, int color)
{
    // first check parameter
    if(x > 128 || y > 32 || x < 0 || y < 0) return;

    if(draw_mode == NORMAL) {
        if(color == 0)
            buffer[x + ((y/8) * 128)] &= ~(1 << (y%8));  // erase pixel
        else
            buffer[x + ((y/8) * 128)] |= (1 << (y%8));   // set pixel
    } else { // XOR mode
        if(color == 1)
            buffer[x + ((y/8) * 128)] ^= (1 << (y%8));   // xor pixel
    }
}

// update lcd

void C12832_LCD::copy_to_lcd(void)
{
#ifndef TARGET_LPC1768
    int i;
#endif
    //page 0
    wr_cmd(0x00);      // set column low nibble 0
    wr_cmd(0x10);      // set column hi  nibble 0
    wr_cmd(0xB0);      // set page address  0
    _A0 = 1;
#if defined TARGET_LPC1768
    _CS = 0;
    // start 128 byte DMA transfer to SPI1
    LPC_GPDMACH0->DMACCDestAddr = (uint32_t)&LPC_SSP1->DR; // we send to SSP1
    LPC_SSP1->DMACR = 0x2;  // Enable SSP1 for DMA.
    LPC_GPDMA->DMACIntTCClear = 0x1;
    LPC_GPDMA->DMACIntErrClr = 0x1;
    LPC_GPDMACH0->DMACCSrcAddr = (uint32_t) (buffer);
    LPC_GPDMACH0->DMACCControl = 128 | (1UL << 31) |  DMA_CHANNEL_SRC_INC ; // 8 bit transfer , address increment, interrupt
    LPC_GPDMACH0->DMACCConfig  = DMA_CHANNEL_ENABLE | DMA_TRANSFER_TYPE_M2P | DMA_DEST_SSP1_TX;
    LPC_GPDMA->DMACSoftSReq = 0x1;
    do {
    } while ((LPC_GPDMA->DMACRawIntTCStat & 0x01) == 0); // DMA is running
    do {
    } while ((LPC_SSP1->SR & 0x10) == 0x10); // SPI1 not idle
    _CS = 1;
#else  // no DMA
    for(i=0; i<128; i++) {
        wr_dat(buffer[i]);
    }
#endif

    // page 1
    wr_cmd(0x00);      // set column low nibble 0
    wr_cmd(0x10);      // set column hi  nibble 0
    wr_cmd(0xB1);      // set page address  1
    _A0 = 1;
#if defined TARGET_LPC1768
    _CS = 0;
    // start 128 byte DMA transfer to SPI1
    LPC_GPDMA->DMACIntTCClear = 0x1;
    LPC_GPDMA->DMACIntErrClr = 0x1;
    LPC_GPDMACH0->DMACCSrcAddr = (uint32_t) (buffer + 128);
    LPC_GPDMACH0->DMACCControl = 128 | (1UL << 31) |  DMA_CHANNEL_SRC_INC ; // 8 bit transfer , address increment, interrupt
    LPC_GPDMACH0->DMACCConfig  = DMA_CHANNEL_ENABLE | DMA_TRANSFER_TYPE_M2P | DMA_DEST_SSP1_TX;
    LPC_GPDMA->DMACSoftSReq = 0x1;
    do {
    } while ((LPC_GPDMA->DMACRawIntTCStat & 0x01) == 0); // DMA is running
    do {
    } while ((LPC_SSP1->SR & 0x10) == 0x10); // SPI1 not idle
    _CS = 1;
#else // no DMA
    for(i=128; i<256; i++) {
        wr_dat(buffer[i]);
    }
#endif

    //page 2
    wr_cmd(0x00);      // set column low nibble 0
    wr_cmd(0x10);      // set column hi  nibble 0
    wr_cmd(0xB2);      // set page address  2
    _A0 = 1;
#if defined TARGET_LPC1768
    _CS = 0;
    // start 128 byte DMA transfer to SPI1
    LPC_GPDMA->DMACIntTCClear = 0x1;
    LPC_GPDMA->DMACIntErrClr = 0x1;
    LPC_GPDMACH0->DMACCSrcAddr = (uint32_t) (buffer + 256);
    LPC_GPDMACH0->DMACCControl = 128 | (1UL << 31) |  DMA_CHANNEL_SRC_INC ; // 8 bit transfer , address increment, interrupt
    LPC_GPDMACH0->DMACCConfig  = DMA_CHANNEL_ENABLE | DMA_TRANSFER_TYPE_M2P | DMA_DEST_SSP1_TX ;
    LPC_GPDMA->DMACSoftSReq = 0x1;
    do {
    } while ((LPC_GPDMA->DMACRawIntTCStat & 0x01) == 0); // DMA is running
    do {
    } while ((LPC_SSP1->SR & 0x10) == 0x10); // SPI1 not idle
    _CS = 1;
#else // no DMA
    for(i=256; i<384; i++) {
        wr_dat(buffer[i]);
    }
#endif

    //page 3
    wr_cmd(0x00);      // set column low nibble 0
    wr_cmd(0x10);      // set column hi  nibble 0
    wr_cmd(0xB3);      // set page address  3
    _A0 = 1;

    _CS = 0;
#if defined TARGET_LPC1768
    // start 128 byte DMA transfer to SPI1
    LPC_GPDMA->DMACIntTCClear = 0x1;
    LPC_GPDMA->DMACIntErrClr = 0x1;
    LPC_GPDMACH0->DMACCSrcAddr = (uint32_t) (buffer + 384);
    LPC_GPDMACH0->DMACCControl = 128  | (1UL << 31) |  DMA_CHANNEL_SRC_INC ; // 8 bit transfer , address increment, interrupt
    LPC_GPDMACH0->DMACCConfig  = DMA_CHANNEL_ENABLE | DMA_TRANSFER_TYPE_M2P | DMA_DEST_SSP1_TX;
    LPC_GPDMA->DMACSoftSReq = 0x1;
    do {
    } while ((LPC_GPDMA->DMACRawIntTCStat & 0x01) == 0); // DMA is running
    do {
    } while ((LPC_SSP1->SR & 0x10) == 0x10); // SPI1 not idle
    _CS = 1;
#else // no DMA
    for(i=384; i<512; i++) {
        wr_dat(buffer[i]);
    }
#endif
}

void C12832_LCD::cls(void)
{
    memset(buffer,0x00,512);  // clear display buffer
    copy_to_lcd();
}


void C12832_LCD::line(int x0, int y0, int x1, int y1, int color)
{
    int   dx = 0, dy = 0;
    int   dx_sym = 0, dy_sym = 0;
    int   dx_x2 = 0, dy_x2 = 0;
    int   di = 0;

    dx = x1-x0;
    dy = y1-y0;

    //  if (dx == 0) {        /* vertical line */
    //      if (y1 > y0) vline(x0,y0,y1,color);
    //      else vline(x0,y1,y0,color);
    //      return;
    //  }

    if (dx > 0) {
        dx_sym = 1;
    } else {
        dx_sym = -1;
    }
    //  if (dy == 0) {        /* horizontal line */
    //      if (x1 > x0) hline(x0,x1,y0,color);
    //      else  hline(x1,x0,y0,color);
    //      return;
    //  }

    if (dy > 0) {
        dy_sym = 1;
    } else {
        dy_sym = -1;
    }

    dx = dx_sym*dx;
    dy = dy_sym*dy;

    dx_x2 = dx*2;
    dy_x2 = dy*2;

    if (dx >= dy) {
        di = dy_x2 - dx;
        while (x0 != x1) {

            pixel(x0, y0, color);
            x0 += dx_sym;
            if (di<0) {
                di += dy_x2;
            } else {
                di += dy_x2 - dx_x2;
                y0 += dy_sym;
            }
        }
        pixel(x0, y0, color);
    } else {
        di = dx_x2 - dy;
        while (y0 != y1) {
            pixel(x0, y0, color);
            y0 += dy_sym;
            if (di < 0) {
                di += dx_x2;
            } else {
                di += dx_x2 - dy_x2;
                x0 += dx_sym;
            }
        }
        pixel(x0, y0, color);
    }
    if(auto_up) copy_to_lcd();
}

void C12832_LCD::rect(int x0, int y0, int x1, int y1, int color)
{

    if (x1 > x0) line(x0,y0,x1,y0,color);
    else  line(x1,y0,x0,y0,color);

    if (y1 > y0) line(x0,y0,x0,y1,color);
    else line(x0,y1,x0,y0,color);

    if (x1 > x0) line(x0,y1,x1,y1,color);
    else  line(x1,y1,x0,y1,color);

    if (y1 > y0) line(x1,y0,x1,y1,color);
    else line(x1,y1,x1,y0,color);

    if(auto_up) copy_to_lcd();
}

void C12832_LCD::fillrect(int x0, int y0, int x1, int y1, int color)
{
    int l,c,i;
    if(x0 > x1) {
        i = x0;
        x0 = x1;
        x1 = i;
    }

    if(y0 > y1) {
        i = y0;
        y0 = y1;
        y1 = i;
    }

    for(l = x0; l<= x1; l ++) {
        for(c = y0; c<= y1; c++) {
            pixel(l,c,color);
        }
    }
    if(auto_up) copy_to_lcd();
}



void C12832_LCD::circle(int x0, int y0, int r, int color)
{

    int draw_x0, draw_y0;
    int draw_x1, draw_y1;
    int draw_x2, draw_y2;
    int draw_x3, draw_y3;
    int draw_x4, draw_y4;
    int draw_x5, draw_y5;
    int draw_x6, draw_y6;
    int draw_x7, draw_y7;
    int xx, yy;
    int di;
    //WindowMax();
    if (r == 0) {       /* no radius */
        return;
    }

    draw_x0 = draw_x1 = x0;
    draw_y0 = draw_y1 = y0 + r;
    if (draw_y0 < height()) {
        pixel(draw_x0, draw_y0, color);     /* 90 degree */
    }

    draw_x2 = draw_x3 = x0;
    draw_y2 = draw_y3 = y0 - r;
    if (draw_y2 >= 0) {
        pixel(draw_x2, draw_y2, color);    /* 270 degree */
    }

    draw_x4 = draw_x6 = x0 + r;
    draw_y4 = draw_y6 = y0;
    if (draw_x4 < width()) {
        pixel(draw_x4, draw_y4, color);     /* 0 degree */
    }

    draw_x5 = draw_x7 = x0 - r;
    draw_y5 = draw_y7 = y0;
    if (draw_x5>=0) {
        pixel(draw_x5, draw_y5, color);     /* 180 degree */
    }

    if (r == 1) {
        return;
    }

    di = 3 - 2*r;
    xx = 0;
    yy = r;
    while (xx < yy) {

        if (di < 0) {
            di += 4*xx + 6;
        } else {
            di += 4*(xx - yy) + 10;
            yy--;
            draw_y0--;
            draw_y1--;
            draw_y2++;
            draw_y3++;
            draw_x4--;
            draw_x5++;
            draw_x6--;
            draw_x7++;
        }
        xx++;
        draw_x0++;
        draw_x1--;
        draw_x2++;
        draw_x3--;
        draw_y4++;
        draw_y5++;
        draw_y6--;
        draw_y7--;

        if ( (draw_x0 <= width()) && (draw_y0>=0) ) {
            pixel(draw_x0, draw_y0, color);
        }

        if ( (draw_x1 >= 0) && (draw_y1 >= 0) ) {
            pixel(draw_x1, draw_y1, color);
        }

        if ( (draw_x2 <= width()) && (draw_y2 <= height()) ) {
            pixel(draw_x2, draw_y2, color);
        }

        if ( (draw_x3 >=0 ) && (draw_y3 <= height()) ) {
            pixel(draw_x3, draw_y3, color);
        }

        if ( (draw_x4 <= width()) && (draw_y4 >= 0) ) {
            pixel(draw_x4, draw_y4, color);
        }

        if ( (draw_x5 >= 0) && (draw_y5 >= 0) ) {
            pixel(draw_x5, draw_y5, color);
        }
        if ( (draw_x6 <=width()) && (draw_y6 <= height()) ) {
            pixel(draw_x6, draw_y6, color);
        }
        if ( (draw_x7 >= 0) && (draw_y7 <= height()) ) {
            pixel(draw_x7, draw_y7, color);
        }
    }
    if(auto_up) copy_to_lcd();
}

void C12832_LCD::fillcircle(int x, int y, int r, int color)
{
    int i,up;
    up = auto_up;
    auto_up = 0;   // off
    for (i = 0; i <= r; i++)
        circle(x,y,i,color);
    auto_up = up;
    if(auto_up) copy_to_lcd();
}

void C12832_LCD::setmode(int mode)
{
    draw_mode = mode;
}

void C12832_LCD::locate(int x, int y)
{
    char_x = x;
    char_y = y;
}



int C12832_LCD::columns()
{
    return width() / font[1];
}



int C12832_LCD::rows()
{
    return height() / font[2];
}



int C12832_LCD::_putc(int value)
{
    if (value == '\n') {    // new line
        char_x = 0;
        char_y = char_y + font[2];
        if (char_y >= height() - font[2]) {
            char_y = 0;
        }
    } else {
        character(char_x, char_y, value);
        if(auto_up) copy_to_lcd();
    }
    return value;
}

void C12832_LCD::character(int x, int y, int c)
{
    unsigned int hor,vert,offset,bpl,j,i,b;
    unsigned char* zeichen;
    unsigned char z,w;

    if ((c < 31) || (c > 127)) return;   // test char range

    // read font parameter from start of array
    offset = font[0];                    // bytes / char
    hor = font[1];                       // get hor size of font
    vert = font[2];                      // get vert size of font
    bpl = font[3];                       // bytes per line

    if (char_x + hor > width()) {
        char_x = 0;
        char_y = char_y + vert;
        if (char_y >= height() - font[2]) {
            char_y = 0;
        }
    }

    zeichen = &font[((c -32) * offset) + 4]; // start of char bitmap
    w = zeichen[0];                          // width of actual char
    // construct the char into the buffer
    for (j=0; j<vert; j++) {  //  vert line
        for (i=0; i<hor; i++) {   //  horz line
            z =  zeichen[bpl * i + ((j & 0xF8) >> 3)+1];
            b = 1 << (j & 0x07);
            if (( z & b ) == 0x00) {
                pixel(x+i,y+j,0);
            } else {
                pixel(x+i,y+j,1);
            }

        }
    }

    char_x += w;
}


void C12832_LCD::set_font(unsigned char* f)
{
    font = f;
}

void C12832_LCD::set_auto_up(unsigned int up)
{
    if(up ) auto_up = 1;
    else auto_up = 0;
}

unsigned int C12832_LCD::get_auto_up(void)
{
    return (auto_up);
}

void C12832_LCD::print_bm(Bitmap bm, int x, int y)
{
    int h,v,b;
    char d;

    for(v=0; v < bm.ySize; v++) {   // lines
        for(h=0; h < bm.xSize; h++) { // pixel
            if(h + x > 127) break;
            if(v + y > 31) break;
            d = bm.data[bm.Byte_in_Line * v + ((h & 0xF8) >> 3)];
            b = 0x80 >> (h & 0x07);
            if((d & b) == 0) {
                pixel(x+h,y+v,0);
            } else {
                pixel(x+h,y+v,1);
            }
        }
    }

}