N5110.cpp

00001 #include "mbed.h"
00002 #include "N5110.h"
00003 
00004 // overloaded constructor includes power pin - LCD Vcc connected to GPIO pin
00005 // this constructor works fine with LPC1768 - enough current sourced from GPIO
00006 // to power LCD. Doesn't work well with K64F.
00007 N5110::N5110(PinName const pwrPin,
00008              PinName const scePin,
00009              PinName const rstPin,
00010              PinName const dcPin,
00011              PinName const mosiPin,
00012              PinName const sclkPin,
00013              PinName const ledPin)
00014     :
00015     _spi(new SPI(mosiPin,NC,sclkPin)), // create new SPI instance and initialise
00016     _led(new DigitalOut(ledPin)),
00017     _pwr(new DigitalOut(pwrPin)),
00018     _sce(new DigitalOut(scePin)),
00019     _rst(new DigitalOut(rstPin)),
00020     _dc(new DigitalOut(dcPin))
00021 {}
00022 
00023 // overloaded constructor does not include power pin - LCD Vcc must be tied to +3V3
00024 // Best to use this with K64F as the GPIO hasn't sufficient output current to reliably
00025 // drive the LCD.
00026 N5110::N5110(PinName const scePin,
00027              PinName const rstPin,
00028              PinName const dcPin,
00029              PinName const mosiPin,
00030              PinName const sclkPin,
00031              PinName const ledPin)
00032     :
00033     _spi(new SPI(mosiPin,NC,sclkPin)), // create new SPI instance and initialise
00034     _led(new DigitalOut(ledPin)),
00035     _pwr(NULL), // pwr not needed so null it to be safe
00036     _sce(new DigitalOut(scePin)),
00037     _rst(new DigitalOut(rstPin)),
00038     _dc(new DigitalOut(dcPin))
00039 {}
00040 
00041 
00042 N5110::~N5110()
00043 {
00044     delete _spi;
00045 
00046     if(_pwr) {
00047         delete _pwr;
00048     }
00049 
00050     delete _led;
00051     delete _sce;
00052     delete _rst;
00053     delete _dc;
00054 }
00055 
00056 // initialise function - powers up and sends the initialisation commands
00057 void N5110::init()
00058 {
00059     turnOn();     // power up
00060     reset();      // reset LCD - must be done within 100 ms
00061     initSPI();    
00062     
00063     backLightOn();
00064     setContrast(0.55);  // this may need tuning (say 0.4 to 0.6)
00065     setBias(3);   // datasheet - 48:1 mux - don't mess with if you don't know what you're doing! (0 to 7)
00066     setTempCoefficient(0); // datasheet - may need increasing (range 0 to 3) at very low temperatures
00067     normalMode();  // normal video mode by default
00068     
00069     clearRAM();      // RAM is undefined at power-up so clear to be sure
00070     clear();   // clear buffer
00071 }
00072 
00073 // sets normal video mode (black on white)
00074 void N5110::normalMode()
00075 {
00076     sendCommand(0b00100000);   // basic instruction
00077     sendCommand(0b00001100);  // normal video mode- datasheet
00078 }
00079 
00080 // sets normal video mode (white on black)
00081 void N5110::inverseMode()
00082 {
00083     sendCommand(0b00100000);   // basic instruction
00084     sendCommand(0b00001101);   // inverse video mode - datasheet
00085 }
00086 
00087 // function to power up the LCD and backlight - only works when using GPIO to power
00088 void N5110::turnOn()
00089 {
00090     if (_pwr != NULL) {
00091         _pwr->write(1);  // apply power
00092     }
00093 }
00094 
00095 // function to power down LCD
00096 void N5110::turnOff()
00097 {
00098     clear(); // clear buffer
00099     refresh();
00100     backLightOff(); // turn backlight off
00101     clearRAM();   // clear RAM to ensure specified current consumption
00102     // send command to ensure we are in basic mode
00103     
00104     sendCommand(0b00100000); // basic mode
00105     sendCommand(0b00001000); // clear display
00106     sendCommand(0b00100001); // extended mode
00107     sendCommand(0b00100100); // power down
00108     
00109     // if we are powering the LCD using the GPIO then make it low to turn off
00110     if (_pwr != NULL) {
00111         thread_sleep_for(10);  // small delay and then turn off the power pin
00112         _pwr->write(0);  // turn off power
00113     }
00114 
00115 }
00116 
00117 // function to change LED backlight brightness
00118 void N5110::backLightOn()
00119 {
00120     _led->write(1);
00121 }
00122 
00123 // function to change LED backlight brightness
00124 void N5110::backLightOff()
00125 {
00126     _led->write(0);
00127 }
00128 
00129 void N5110::setContrast(float contrast) {
00130     
00131     // enforce limits
00132     if (contrast > 1.0f)
00133         contrast = 1.0f;
00134     else if (contrast < 0.0f)
00135         contrast = 0.0;
00136     
00137     // convert to char in range 0 to 127 (i.e. 6 bits)
00138     char ic = char(contrast*127.0f);
00139     
00140     sendCommand(0b00100001);  // extended instruction set
00141     sendCommand(0b10000000 | ic);   // set Vop (which controls contrast)
00142     sendCommand(0b00100000);  // back to basic instruction set
00143 }
00144 
00145 void N5110::setTempCoefficient(char tc) {
00146     
00147     // enforce limits
00148     if (tc>3) {
00149         tc=3;
00150     }
00151     
00152     // temperature coefficient may need increasing at low temperatures
00153 
00154     sendCommand(0b00100001);  // extended instruction set
00155     sendCommand(0b00000100 | tc);
00156     sendCommand(0b00100000);  // back to basic instruction set
00157 }
00158     
00159 void N5110::setBias(char bias) {
00160     
00161     // from data sheet
00162     // bias      mux rate
00163     // 0        1:100
00164     // 1        1:80
00165     // 2        1:65
00166     // 3        1:48   (default)
00167     // 4        1:40/1:34
00168     // 5        1:24
00169     // 6        1:18/1:16
00170     // 7        1:10/1:9/1:8
00171     
00172     // enforce limits
00173     if (bias>7) {
00174         bias=7;
00175     }
00176         
00177     sendCommand(0b00100001);  // extended mode instruction
00178     sendCommand(0b00010000 | bias);  
00179     sendCommand(0b00100000); // end of extended mode instruction
00180 }
00181 
00182 // pulse the active low reset line
00183 void N5110::reset()
00184 {
00185     _rst->write(0);  // reset the LCD
00186     _rst->write(1);
00187 }
00188 
00189 // function to initialise SPI peripheral
00190 void N5110::initSPI()
00191 {
00192     _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
00193     _spi->frequency(4000000);  // maximum of screen is 4 MHz
00194 }
00195 
00196 // send a command to the display
00197 void N5110::sendCommand(unsigned char command)
00198 {
00199     _dc->write(0);  // set DC low for command
00200     _sce->write(0); // set CE low to begin frame
00201     _spi->write(command);  // send command
00202     _dc->write(1);  // turn back to data by default
00203     _sce->write(1); // set CE high to end frame (expected for transmission of single byte)
00204 }
00205 
00206 // send data to the display at the current XY address
00207 // dc is set to 1 (i.e. data) after sending a command and so should
00208 // be the default mode.
00209 void N5110::sendData(unsigned char data)
00210 {
00211     _sce->write(0);   // set CE low to begin frame
00212     _spi->write(data);
00213     _sce->write(1);  // set CE high to end frame (expected for transmission of single byte)
00214 }
00215 
00216 // this function writes 0 to the 504 bytes to clear the RAM
00217 void N5110::clearRAM()
00218 {
00219     _sce->write(0);  //set CE low to begin frame
00220     for(int i = 0; i < WIDTH * HEIGHT; i++) { // 48 x 84 bits = 504 bytes
00221         _spi->write(0x00);  // send 0's
00222     }
00223     _sce->write(1); // set CE high to end frame
00224 }
00225 
00226 // function to set the XY address in RAM for subsequenct data write
00227 void N5110::setXYAddress(unsigned int const x,
00228                          unsigned int const y)
00229 {
00230     if (x<WIDTH && y<HEIGHT) {  // check within range
00231         sendCommand(0b00100000);  // basic instruction
00232         sendCommand(0b10000000 | x);  // send addresses to display with relevant mask
00233         sendCommand(0b01000000 | y);
00234     }
00235 }
00236 
00237 // These functions are used to set, clear and get the value of pixels in the display
00238 // Pixels are addressed in the range of 0 to 47 (y) and 0 to 83 (x).  The refresh()
00239 // function must be called after set and clear in order to update the display
00240 void N5110::setPixel(unsigned int const x,
00241                      unsigned int const y,
00242                      bool const         state)
00243 {
00244     if (x<WIDTH && y<HEIGHT) {  // check within range
00245         // calculate bank and shift 1 to required position in the data byte
00246         if(state) buffer[x][y/8] |= (1 << y%8);
00247         else      buffer[x][y/8] &= ~(1 << y%8);
00248     }
00249 }
00250 
00251 void N5110::clearPixel(unsigned int const x,
00252                        unsigned int const y)
00253 {
00254     if (x<WIDTH && y<HEIGHT) {  // check within range
00255         // calculate bank and shift 1 to required position (using bit clear)
00256         buffer[x][y/8] &= ~(1 << y%8);
00257     }
00258 }
00259 
00260 int N5110::getPixel(unsigned int const x,
00261                     unsigned int const y) const
00262 {
00263     if (x<WIDTH && y<HEIGHT) {  // check within range
00264         // return relevant bank and mask required bit
00265 
00266         int pixel = (int) buffer[x][y/8] & (1 << y%8);
00267 
00268         if (pixel)
00269             return 1;
00270         else
00271             return 0;
00272     }
00273 
00274     return 0;
00275 
00276 }
00277 
00278 // function to refresh the display
00279 void N5110::refresh()
00280 {
00281     setXYAddress(0,0);  // important to set address back to 0,0 before refreshing display
00282     // address auto increments after printing string, so buffer[0][0] will not coincide
00283     // with top-left pixel after priting string
00284 
00285     _sce->write(0);  //set CE low to begin frame
00286 
00287     for(int j = 0; j < BANKS; j++) {  // be careful to use correct order (j,i) for horizontal addressing
00288         for(int i = 0; i < WIDTH; i++) {
00289             _spi->write(buffer[i][j]);  // send buffer
00290         }
00291     }
00292     _sce->write(1); // set CE high to end frame
00293 
00294 }
00295 
00296 // fills the buffer with random bytes.  Can be used to test the display.
00297 // The rand() function isn't seeded so it probably creates the same pattern everytime
00298 void N5110::randomiseBuffer()
00299 {
00300     int i,j;
00301     for(j = 0; j < BANKS; j++) {  // be careful to use correct order (j,i) for horizontal addressing
00302         for(i = 0; i < WIDTH; i++) {
00303             buffer[i][j] = rand()%256;  // generate random byte
00304         }
00305     }
00306 
00307 }
00308 
00309 // function to print 5x7 font
00310 void N5110::printChar(char const          c,
00311                       unsigned int const  x,
00312                       unsigned int const  y)
00313 {
00314     if (y<BANKS) {  // check if printing in range of y banks
00315 
00316         for (int i = 0; i < 5 ; i++ ) {
00317             int pixel_x = x+i;
00318             if (pixel_x > WIDTH-1)  // ensure pixel isn't outside the buffer size (0 - 83)
00319                 break;
00320             buffer[pixel_x][y] = font5x7[(c - 32)*5 + i];
00321             // array is offset by 32 relative to ASCII, each character is 5 pixels wide
00322         }
00323 
00324     }
00325 }
00326 
00327 // function to print string at specified position
00328 void N5110::printString(const char         *str,
00329                         unsigned int const  x,
00330                         unsigned int const  y)
00331 {
00332     if (y<BANKS) {  // check if printing in range of y banks
00333 
00334         int n = 0 ; // counter for number of characters in string
00335         // loop through string and print character
00336         while(*str) {
00337 
00338             // writes the character bitmap data to the buffer, so that
00339             // text and pixels can be displayed at the same time
00340             for (int i = 0; i < 5 ; i++ ) {
00341                 int pixel_x = x+i+n*6;
00342                 if (pixel_x > WIDTH-1) // ensure pixel isn't outside the buffer size (0 - 83)
00343                     break;
00344                 buffer[pixel_x][y] = font5x7[(*str - 32)*5 + i];
00345             }
00346             str++;  // go to next character in string
00347             n++;    // increment index
00348         }
00349     }
00350 }
00351 
00352 // function to clear the screen buffer
00353 void N5110::clear()
00354 {
00355     memset(buffer,0,sizeof(buffer));
00356 }
00357 
00358 // function to plot array on display
00359 void N5110::plotArray(float const array[])
00360 {
00361     for (int i=0; i<WIDTH; i++) {  // loop through array
00362         // elements are normalised from 0.0 to 1.0, so multiply
00363         // by 47 to convert to pixel range, and subtract from 47
00364         // since top-left is 0,0 in the display geometry
00365         setPixel(i,47 - int(array[i]*47.0f),true);
00366     }
00367 
00368 }
00369 
00370 // function to draw circle
00371 void N5110:: drawCircle(unsigned int const x0,
00372                         unsigned int const y0,
00373                         unsigned int const radius,
00374                         FillType const     fill)
00375 {
00376     // from http://en.wikipedia.org/wiki/Midpoint_circle_algorithm
00377     int x = radius;
00378     int y = 0;
00379     int radiusError = 1-x;
00380 
00381     while(x >= y) {
00382 
00383         // if transparent, just draw outline
00384         if (fill == FILL_TRANSPARENT) {
00385             setPixel( x + x0,  y + y0,true);
00386             setPixel(-x + x0,  y + y0,true);
00387             setPixel( y + x0,  x + y0,true);
00388             setPixel(-y + x0,  x + y0,true);
00389             setPixel(-y + x0, -x + y0,true);
00390             setPixel( y + x0, -x + y0,true);
00391             setPixel( x + x0, -y + y0,true);
00392             setPixel(-x + x0, -y + y0,true);
00393         } else {  // drawing filled circle, so draw lines between points at same y value
00394 
00395             int type = (fill==FILL_BLACK) ? 1:0;  // black or white fill
00396 
00397             drawLine(x+x0,y+y0,-x+x0,y+y0,type);
00398             drawLine(y+x0,x+y0,-y+x0,x+y0,type);
00399             drawLine(y+x0,-x+y0,-y+x0,-x+y0,type);
00400             drawLine(x+x0,-y+y0,-x+x0,-y+y0,type);
00401         }
00402 
00403         y++;
00404         if (radiusError<0) {
00405             radiusError += 2 * y + 1;
00406         } else {
00407             x--;
00408             radiusError += 2 * (y - x) + 1;
00409         }
00410     }
00411 
00412 }
00413 
00414 void N5110::drawLine(unsigned int const x0,
00415                      unsigned int const y0,
00416                      unsigned int const x1,
00417                      unsigned int const y1,
00418                      unsigned int const type)
00419 {
00420     // Note that the ranges can be negative so we have to turn the input values
00421     // into signed integers first
00422     int const y_range = static_cast<int>(y1) - static_cast<int>(y0);
00423     int const x_range = static_cast<int>(x1) - static_cast<int>(x0);
00424 
00425     // if dotted line, set step to 2, else step is 1
00426     unsigned int const step = (type==2) ? 2:1;
00427 
00428     // make sure we loop over the largest range to get the most pixels on the display
00429     // for instance, if drawing a vertical line (x_range = 0), we need to loop down the y pixels
00430     // or else we'll only end up with 1 pixel in the x column
00431     if ( abs(x_range) > abs(y_range) ) {
00432 
00433         // ensure we loop from smallest to largest or else for-loop won't run as expected
00434         unsigned int const start = x_range > 0 ? x0:x1;
00435         unsigned int const stop =  x_range > 0 ? x1:x0;
00436 
00437         // loop between x pixels
00438         for (unsigned int x = start; x<= stop ; x+=step) {
00439             // do linear interpolation
00440             int const dx = static_cast<int>(x)-static_cast<int>(x0);
00441             unsigned int const y = y0 + y_range * dx / x_range;
00442 
00443             // If the line type is '0', this will clear the pixel
00444             // If it is '1' or '2', the pixel will be set
00445             setPixel(x,y, type);
00446         }
00447     } else {
00448 
00449         // ensure we loop from smallest to largest or else for-loop won't run as expected
00450         unsigned int const start = y_range > 0 ? y0:y1;
00451         unsigned int const stop =  y_range > 0 ? y1:y0;
00452 
00453         for (unsigned int y = start; y<= stop ; y+=step) {
00454             // do linear interpolation
00455             int const dy = static_cast<int>(y)-static_cast<int>(y0);
00456             unsigned int const x = x0 + x_range * dy / y_range;
00457 
00458             // If the line type is '0', this will clear the pixel
00459             // If it is '1' or '2', the pixel will be set
00460             setPixel(x,y, type);
00461         }
00462     }
00463 
00464 }
00465 
00466 void N5110::drawRect(unsigned int const x0,
00467                      unsigned int const y0,
00468                      unsigned int const width,
00469                      unsigned int const height,
00470                      FillType const     fill)
00471 {
00472     if (fill == FILL_TRANSPARENT) { // transparent, just outline
00473         drawLine(x0,y0,x0+(width-1),y0,1);  // top
00474         drawLine(x0,y0+(height-1),x0+(width-1),y0+(height-1),1);  // bottom
00475         drawLine(x0,y0,x0,y0+(height-1),1);  // left
00476         drawLine(x0+(width-1),y0,x0+(width-1),y0+(height-1),1);  // right
00477     } else { // filled rectangle
00478         int type = (fill==FILL_BLACK) ? 1:0;  // black or white fill
00479         for (int y = y0; y<y0+height; y++) {  // loop through rows of rectangle
00480             drawLine(x0,y,x0+(width-1),y,type);  // draw line across screen
00481         }
00482     }
00483 }
00484 
00485 void N5110::drawSprite(int x0,
00486                        int y0,
00487                        int nrows,
00488                        int ncols,
00489                        int *sprite)
00490 {
00491     for (int i = 0; i < nrows; i++) {
00492         for (int j = 0 ; j < ncols ; j++) {
00493 
00494             int pixel = *((sprite+i*ncols)+j);
00495             setPixel(x0+j,y0+i, pixel);
00496         }
00497     }
00498 }