File content as of revision 23:eb7e6632fc9e:

/**
@file N5110.cpp

@brief Member functions implementations

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

// overloaded constructor includes power pin - LCD Vcc connected to GPIO pin
// this constructor works fine with LPC1768 - enough current sourced from GPIO
// to power LCD. Doesn't work well with K64F.
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

  // 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);

  clearBuffer();
}

// overloaded constructor does not include power pin - LCD Vcc must be tied to +3V3
// Best to use this with K64F as the GPIO hasn't sufficient output current to reliably
// drive the LCD.
N5110::N5110(PinName scePin, PinName rstPin, PinName dcPin, PinName mosiPin, PinName sclkPin, PinName ledPin)
{
  spi = new SPI(mosiPin,NC,sclkPin); // create new SPI instance and initialise
  // set up pins as required
  pwr = NULL;
  led = new PwmOut(ledPin);
  sce = new DigitalOut(scePin);
  rst = new DigitalOut(rstPin);
  dc = new DigitalOut(dcPin);

  clearBuffer();

}

// initialise function - powers up and sends the initialisation commands
void N5110::init()
{
  turnOn();     // power up
  reset();      // reset LCD - must be done within 100 ms

  initSPI();
  // function set - extended
  sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_EXTENDED_MODE);
  //printf("*");
  // 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();
  clear();
  setBrightness(0.5);
}

// 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()
{
  if (pwr != NULL) {
    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);

  // if we are powering the LCD using the GPIO then make it low to turn off
  if (pwr != NULL) {
    pwr->write(0);  // turn off power
  }

}

// function to change LED backlight brightness
void N5110::setBrightness(float brightness)
{
  // check whether brightness is within range
  if (brightness < 0.0f)
  brightness = 0.0f;
  if (brightness > 1.0f)
  brightness = 1.0f;
  // 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
}

// 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()
{
  sce->write(0);  //set CE low to begin frame
  for(int 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);
  }
}

// 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::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] |= (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] &= ~(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] & (1 << y%8);
    // note this does not necessarily return 1 - a non-zero number represents a pixel
  } else {
    return 0;
  }
}

// function to refresh the display
void N5110::refresh()
{

  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(int j = 0; j < BANKS; j++) {  // be careful to use correct order (j,i) for horizontal addressing
    for(int i = 0; i < WIDTH; i++) {
      spi->write(buffer[i][j]);  // 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] = rand()%256;  // generate random byte
    }
  }

}

// function to print 5x7 font
void N5110::printChar(char c,int x,int y)
{
  if (y>=0 && y<BANKS) {  // check if printing in range of y banks

    for (int i = 0; i < 5 ; i++ ) {
      int pixel_x = x+i;
      if (pixel_x > WIDTH-1)  // ensure pixel isn't outside the buffer size (0 - 83)
      break;
      buffer[pixel_x][y] = 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)
{
  if (y>=0 && y<BANKS) {  // check if printing in range of y banks

    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++ ) {
        int pixel_x = x+i+n*6;
        if (pixel_x > WIDTH-1) // ensure pixel isn't outside the buffer size (0 - 83)
        break;
        buffer[pixel_x][y] = 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()
{
  memset(buffer,0,sizeof(buffer));

  /*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]=0;
    }
  }
  */
}

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

  for (int 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]*47.0f));
  }

  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;
    }
  }

}

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

    }
  }

}

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
    }
  }

}