Simple library for interfacing to Nokia 5110 LCD display (as found on the SparkFun website). Created by Craig A. Evans, University of Leeds.

Fork of N5110 by Craig Evans

N5110.cpp

Committer:
eencae
Date:
2014-01-26
Revision:
1:df68f34cd32d
Parent:
0:d563e74f0ae9
Child:
2:e93021cfb0a9

File content as of revision 1:df68f34cd32d:

#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();    
    
    led = new PwmOut(ledPin);
    pwr = new DigitalOut(pwrPin);
    sce = new DigitalOut(scePin);
    rst = new DigitalOut(rstPin);
    dc = new DigitalOut(dcPin);

}

void N5110::init()
{
    turnOn();    // power up
    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);

    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
    //sendCommand(CMD_DC_INVERT_VIDEO);  // white on black

    // 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
    sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_BASIC_MODE);
    sendCommand(CMD_DC_CLEAR_DISPLAY);
    sendCommand(0x20 | CMD_FS_POWER_DOWN_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_EXTENDED_MODE);
    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);
}


// 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
}

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)

}

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 < 504; i++) { // 48 x 84 bits = 504 bytes
        spi->write(0x00);  // send 0's
    }
    sce->write(1); // set CE high to end frame

}

void N5110::setXYAddress(int x, int y)
{

    // check whether address is in range
    if (x > 83)
        x=83;
    if (y > 5)
        y=5;

    sendCommand(0x80 | x);
    sendCommand(0x40 | y);
}

void N5110::setPixel(int x, int y)
{
    // calculate bank and shift 1 to required position
    buffer[x][y/8] |= (1 << y%8);
}

void N5110::clearPixel(int x, int y)
{
    // calculate bank and shift 1 to required position (using bit clear)
    buffer[x][y/8] &= ~(1 << y%8);
}

unsigned char N5110::getPixel(int x, int y)
{
    // return relevant bank and mask required bit
    return buffer[x][y/8] & (1 << y%8);

}

void N5110::refreshDisplay()
{

    int i,j;
    sce->write(0);  //set CE low to begin frame

    for(j = 0; j < 6; j++) {  // be careful to use correct order (j,i) for horizontal addressing
        for(i = 0; i < 84; i++) {
            spi->write(buffer[i][j]);  // send buffer
        }
    }
    sce->write(1); // set CE high to end frame

}

void N5110::randomiseBuffer()
{

    int i,j;

    for(j = 0; j < 6; j++) {  // be careful to use correct order (j,i) for horizontal addressing
        for(i = 0; i < 84; i++) {
            buffer[i][j] = rand()%256;  // generate random byte
        }
    }

}

// function to print 5x7 font
void N5110::printChar(char c)
{

    // loop through 5 columns
    for (int j = 0; j < 5 ; j++ ) {
        sendData(font5x7[(c - 32)*5 + j]);
        // array is offset by 32 relative to ASCII, each character is 5 pixels wide
    }
    
    sendData(0); // send an empty byte to introduce space between characters

}

// 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) {

        setXYAddress(x+6*n,y);  // leave 1 pixel (6 = 5 + 1) between each character
        printChar(*str);
        str++;  // go to next character in string
        n++;    // increment index
    }

}

void N5110::clear()
{
    clearBuffer();
    refreshDisplay();
}

void N5110::clearBuffer()
{
    int i,j;
    for (i=0; i<84; i++) {
        for (j=0; j<6; j++) {
            buffer[i][j]=0;
        }
    }
}