Simple library for interfacing to Nokia 5110 LCD display (as found on the SparkFun website). Edited to include additional feaatures, such as 2d array loading, multiple screen buffers, and better backlight control

Dependencies:   N5110

Dependents:   Main_code_ver18

Fork of N5110 by Craig Evans

N5110.cpp

Committer:
el14pjgn
Date:
2016-05-09
Revision:
18:d2140be00144
Parent:
17:780a542d5f8b

File content as of revision 18:d2140be00144:

/**
@file N5110.cpp

@brief Member functions implementations

*/
#include "mbed.h"
#include "N5110.h"


N5110::N5110(PinName pwrPin, PinName scePin, PinName rstPin, PinName dcPin, PinName mosiPin, PinName sclkPin, PinName ledPin)
{

    spi = new SPI(mosiPin,NC,sclkPin); // create new SPI instance and initialise
    initSPI();

    // set up pins as required
    led = new PwmOut(ledPin);
    pwr = new DigitalOut(pwrPin);
    sce = new DigitalOut(scePin);
    rst = new DigitalOut(rstPin);
    dc = new DigitalOut(dcPin);
    bufferFrameEdit = 1;
    bufferFrameDisplay = 1;

}

// initialise function - powers up and sends the initialisation commands
void N5110::init()
{
    turnOn();     // power up
    wait_ms(10);  // small delay seems to prevent spurious pixels during mbed reset
    reset();      // reset LCD - must be done within 100 ms

    // function set - extended
    sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_EXTENDED_MODE);
    // Don't completely understand these parameters - they seem to work as they are
    // Consult the datasheet if you need to change them
    sendCommand(CMD_VOP_7V38);    // operating voltage - these values are from Chris Yan's Library
    sendCommand(CMD_TC_TEMP_2);   // temperature control
    sendCommand(CMD_BI_MUX_48);   // bias

    // function set - basic
    sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_BASIC_MODE);
    normalMode();  // normal video mode by default
    sendCommand(CMD_DC_NORMAL_MODE);  // black on white

    // RAM is undefined at power-up so clear
    clearRAM();

}

// sets normal video mode (black on white)
void N5110::normalMode()
{
    sendCommand(CMD_DC_NORMAL_MODE);

}

// sets normal video mode (white on black)
void N5110::inverseMode()
{
    sendCommand(CMD_DC_INVERT_VIDEO);
}

// function to power up the LCD and backlight
void N5110::turnOn()
{
    // set brightness of LED - 0.0 to 1.0 - default is 50%
    setBrightness(0.5);
    pwr->write(1);  // apply power
}

// function to power down LCD
void N5110::turnOff()
{
    setBrightness(0.0);  // turn backlight off
    clearRAM();   // clear RAM to ensure specified current consumption
    // send command to ensure we are in basic mode
    sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_BASIC_MODE);
    // clear the display
    sendCommand(CMD_DC_CLEAR_DISPLAY);
    // enter the extended mode and power down
    sendCommand(0x20 | CMD_FS_POWER_DOWN_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_EXTENDED_MODE);
    // small delay and then turn off the power pin
    wait_ms(10);
    pwr->write(0);

}

// function to change LED backlight brightness
void N5110::setBrightness(float brightness)
{
    // check whether brightness is within range
    if (brightness < 0.0)
        brightness = 0.0;
    if (brightness > 1.0)
        brightness = 1.0;
    // set PWM duty cycle
    led->write(brightness);
}

// function to change LED backlight PWM frequency
void N5110::setPwmFreq(float freq)
{
    led->period_us(freq);
}


// pulse the active low reset line
void N5110::reset()
{
    rst->write(0);  // reset the LCD
    rst->write(1);
}

// function to initialise SPI peripheral
void N5110::initSPI()
{
    spi->format(8,1);    // 8 bits, Mode 1 - polarity 0, phase 1 - base value of clock is 0, data captured on falling edge/propagated on rising edge
    spi->frequency(4000000);  // maximum of screen is 4 MHz
}

// send a command to the display
void N5110::sendCommand(unsigned char command)
{
    dc->write(0);  // set DC low for command
    sce->write(0); // set CE low to begin frame
    spi->write(command);  // send command
    dc->write(1);  // turn back to data by default
    sce->write(1); // set CE high to end frame (expected for transmission of single byte)

}

// send data to the display at the current XY address
// dc is set to 1 (i.e. data) after sending a command and so should
// be the default mode.
void N5110::sendData(unsigned char data)
{
    sce->write(0);   // set CE low to begin frame
    spi->write(data);
    sce->write(1);  // set CE high to end frame (expected for transmission of single byte)
}

// this function writes 0 to the 504 bytes to clear the RAM
void N5110::clearRAM()
{
    int i;
    sce->write(0);  //set CE low to begin frame
    for(i = 0; i < WIDTH * HEIGHT; i++) { // 48 x 84 bits = 504 bytes
        spi->write(0x00);  // send 0's
    }
    sce->write(1); // set CE high to end frame

}

// function to set the XY address in RAM for subsequenct data write
void N5110::setXYAddress(int x, int y)
{
    if (x>=0 && x<WIDTH && y>=0 && y<HEIGHT) {  // check within range
        sendCommand(0x80 | x);  // send addresses to display with relevant mask
        sendCommand(0x40 | y);
    }
}

void N5110::selectBuffer(int type,int buffer)
{
    switch(type) {
        case 1: //display
            bufferFrameDisplay = buffer;
            break;
        case 2: //editable
            bufferFrameEdit = buffer;
            break;
        case 3: //both
            bufferFrameEdit = buffer;
            bufferFrameDisplay = buffer;
            break;
    }
}

// These functions are used to set, clear and get the value of pixels in the display
// Pixels are addressed in the range of 0 to 47 (y) and 0 to 83 (x).  The refresh()
// function must be called after set and clear in order to update the display
void N5110::writePixel(int x, int y, int v)
{
    if (x>=0 && x<WIDTH && y>=0 && y<HEIGHT) {  // check within range
        // calculate bank and shift 1 to required position in the data byte
        if(v==1) {
            buffer[x][y/8][bufferFrameEdit] |= (1 << y%8);
        }
        if(v==0) {
            buffer[x][y/8][bufferFrameEdit] &= ~(1 << y%8);
        }
    }
}

void N5110::setPixel(int x, int y)
{
    if (x>=0 && x<WIDTH && y>=0 && y<HEIGHT) {  // check within range
        // calculate bank and shift 1 to required position in the data byte
        buffer[x][y/8][bufferFrameEdit] |= (1 << y%8);
    }
}

void N5110::clearPixel(int x, int y)
{
    if (x>=0 && x<WIDTH && y>=0 && y<HEIGHT) {  // check within range
        // calculate bank and shift 1 to required position (using bit clear)
        buffer[x][y/8][bufferFrameEdit] &= ~(1 << y%8);
    }
}

int N5110::getPixel(int x, int y)
{
    if (x>=0 && x<WIDTH && y>=0 && y<HEIGHT) {  // check within range
        // return relevant bank and mask required bit
        return (int) buffer[x][y/8][bufferFrameEdit] & (1 << y%8);
    } else {
        return 0;
    }
}

// function to refresh the display
void N5110::refresh()
{
    int i,j;

    setXYAddress(0,0);  // important to set address back to 0,0 before refreshing display
    // address auto increments after printing string, so buffer[0][0] will not coincide
    // with top-left pixel after priting string

    sce->write(0);  //set CE low to begin frame

    for(j = 0; j < BANKS; j++) {  // be careful to use correct order (j,i) for horizontal addressing
        for(i = 0; i < WIDTH; i++) {
            spi->write(buffer[i][j][bufferFrameDisplay]);  // send buffer
        }
    }
    sce->write(1); // set CE high to end frame

}

// fills the buffer with random bytes.  Can be used to test the display.
// The rand() function isn't seeded so it probably creates the same pattern everytime
void N5110::randomiseBuffer()
{
    int i,j;
    for(j = 0; j < BANKS; j++) {  // be careful to use correct order (j,i) for horizontal addressing
        for(i = 0; i < WIDTH; i++) {
            buffer[i][j][bufferFrameEdit] = rand()%256;  // generate random byte
        }
    }

}

// function to print 5x7 font
void N5110::printChar(char c,int x,int y)
{
    for (int i = 0; i < 5 ; i++ ) {
        buffer[x+i][y][bufferFrameEdit] = font5x7[(c - 32)*5 + i];
        // array is offset by 32 relative to ASCII, each character is 5 pixels wide
    }

    refresh();  // this sends the buffer to the display and sets address (cursor) back to 0,0
}

// function to print string at specified position
void N5110::printString(const char * str,int x,int y)
{
    int n = 0 ; // counter for number of characters in string
    // loop through string and print character
    while(*str) {

        // writes the character bitmap data to the buffer, so that
        // text and pixels can be displayed at the same time
        for (int i = 0; i < 5 ; i++ ) {
            buffer[x+i+n*6][y][bufferFrameEdit] = font5x7[(*str - 32)*5 + i];
        }

        str++;  // go to next character in string
        n++;    // increment index
    }

    refresh();  // this sends the buffer to the display and sets address (cursor) back to 0,0

}

// function to clear the screen
void N5110::clear()
{
    clearBuffer();  // clear the buffer then call the refresh function
    refresh();
}

// function to clear the buffer
void N5110::clearBuffer()
{
    int i,j;
    for (i=0; i<WIDTH; i++) {  // loop through the banks and set the buffer to 0
        for (j=0; j<BANKS; j++) {
            buffer[i][j][bufferFrameEdit]=0;
        }
    }
}

// function to write array to buffer
void N5110::plotArray2d(bool array2d[][HEIGHT])
{
    int i,j;
    for (i=0; i<=WIDTH; i++) {  // loop through the banks and copy data across
        for (j=0; j<=HEIGHT; j++) {
            writePixel(i,j,array2d[i][j]);
        }
    }
    refresh();
}

// function to write offset 3d array to buffer
void N5110::plotArray3d(bool array3d[][50][2],int z,int off_x, int off_y)
{
    int i,j;
    for (i=0; i<=WIDTH; i++) {  // loop through the banks and copy data across
        for (j=0; j<=HEIGHT; j++) {
            writePixel(i,j,array3d[i-off_x][j-off_y][z]);
        }
    }
    refresh();
}

// function to plot array on display
void N5110::plotArray(float array[])
{

    int i;

    for (i=0; i<WIDTH; i++) {  // loop through array
        // elements are normalised from 0.0 to 1.0, so multiply
        // by 47 to convert to pixel range, and subtract from 47
        // since top-left is 0,0 in the display geometry
        setPixel(i,47 - int(array[i]*47.0));
    }

    refresh();

}

// function to draw circle
void N5110:: drawCircle(int x0,int y0,int radius,int fill)
{
    // from http://en.wikipedia.org/wiki/Midpoint_circle_algorithm
    int x = radius;
    int y = 0;
    int radiusError = 1-x;

    while(x >= y) {

        // if transparent, just draw outline
        if (fill == 0) {
            setPixel( x + x0,  y + y0);
            setPixel(-x + x0,  y + y0);
            setPixel( y + x0,  x + y0);
            setPixel(-y + x0,  x + y0);
            setPixel(-y + x0, -x + y0);
            setPixel( y + x0, -x + y0);
            setPixel( x + x0, -y + y0);
            setPixel(-x + x0, -y + y0);
        } else {  // drawing filled circle, so draw lines between points at same y value

            int type = (fill==1) ? 1:0;  // black or white fill

            drawLine(x+x0,y+y0,-x+x0,y+y0,type);
            drawLine(y+x0,x+y0,-y+x0,x+y0,type);
            drawLine(y+x0,-x+y0,-y+x0,-x+y0,type);
            drawLine(x+x0,-y+y0,-x+x0,-y+y0,type);
        }


        y++;
        if (radiusError<0) {
            radiusError += 2 * y + 1;
        } else {
            x--;
            radiusError += 2 * (y - x) + 1;
        }
    }

    refresh();
}

void N5110::drawLine(int x0,int y0,int x1,int y1,int type)
{
    int y_range = y1-y0;  // calc range of y and x
    int x_range = x1-x0;
    int start,stop,step;

    // if dotted line, set step to 2, else step is 1
    step = (type==2) ? 2:1;

    // make sure we loop over the largest range to get the most pixels on the display
    // for instance, if drawing a vertical line (x_range = 0), we need to loop down the y pixels
    // or else we'll only end up with 1 pixel in the x column
    if ( abs(x_range) > abs(y_range) ) {

        // ensure we loop from smallest to largest or else for-loop won't run as expected
        start = x1>x0 ? x0:x1;
        stop =  x1>x0 ? x1:x0;

        // loop between x pixels
        for (int x = start; x<= stop ; x+=step) {
            // do linear interpolation
            int y = y0 + (y1-y0)*(x-x0)/(x1-x0);

            if (type == 0)   // if 'white' line, turn off pixel
                clearPixel(x,y);
            else
                setPixel(x,y);  // else if 'black' or 'dotted' turn on pixel
        }
    } else {

        // ensure we loop from smallest to largest or else for-loop won't run as expected
        start = y1>y0 ? y0:y1;
        stop =  y1>y0 ? y1:y0;

        for (int y = start; y<= stop ; y+=step) {
            // do linear interpolation
            int x = x0 + (x1-x0)*(y-y0)/(y1-y0);

            if (type == 0)   // if 'white' line, turn off pixel
                clearPixel(x,y);
            else
                setPixel(x,y);  // else if 'black' or 'dotted' turn on pixel

        }
    }

    refresh();
}

void N5110::drawRect(int x0,int y0,int width,int height,int fill)
{

    if (fill == 0) { // transparent, just outline
        drawLine(x0,y0,x0+width,y0,1);  // top
        drawLine(x0,y0+height,x0+width,y0+height,1);  // bottom
        drawLine(x0,y0,x0,y0+height,1);  // left
        drawLine(x0+width,y0,x0+width,y0+height,1);  // right
    } else { // filled rectangle
        int type = (fill==1) ? 1:0;  // black or white fill
        for (int y = y0; y<= y0+height; y++) {  // loop through rows of rectangle
            drawLine(x0,y,x0+width,y,type);  // draw line across screen
        }
    }

}