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 PwmOut(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 PwmOut(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 N5110::~N5110()
00042 {
00043     delete _spi;
00044 
00045     if(_pwr) {
00046         delete _pwr;
00047     }
00048 
00049     delete _led;
00050     delete _sce;
00051     delete _rst;
00052     delete _dc;
00053 }
00054 
00055 // initialise function - powers up and sends the initialisation commands
00056 void N5110::init()
00057 {
00058     turnOn();     // power up
00059     reset();      // reset LCD - must be done within 100 ms
00060 
00061     initSPI();
00062     // function set - extended
00063     sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_EXTENDED_MODE);
00064     // Don't completely understand these parameters - they seem to work as they are
00065     // Consult the datasheet if you need to change them
00066     sendCommand(CMD_VOP_7V38);    // operating voltage - these values are from Chris Yan's Library
00067     sendCommand(CMD_TC_TEMP_2);   // temperature control
00068     sendCommand(CMD_BI_MUX_48);   // changing this can sometimes improve the contrast on some displays
00069 
00070     // function set - basic
00071     sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_BASIC_MODE);
00072     normalMode();  // normal video mode by default
00073     sendCommand(CMD_DC_NORMAL_MODE);  // black on white
00074 
00075     clearRAM();      // RAM is undefined at power-up so clear
00076     clear();   // clear buffer
00077     setBrightness(0.5);
00078 }
00079 
00080 // sets normal video mode (black on white)
00081 void N5110::normalMode()
00082 {
00083     sendCommand(CMD_DC_NORMAL_MODE);
00084 }
00085 
00086 // sets normal video mode (white on black)
00087 void N5110::inverseMode()
00088 {
00089     sendCommand(CMD_DC_INVERT_VIDEO);
00090 }
00091 
00092 // function to power up the LCD and backlight - only works when using GPIO to power
00093 void N5110::turnOn()
00094 {
00095     if (_pwr != NULL) {
00096         _pwr->write(1);  // apply power
00097     }
00098 }
00099 
00100 // function to power down LCD
00101 void N5110::turnOff()
00102 {
00103     clear(); // clear buffer
00104     refresh();
00105     setBrightness(0.0);  // turn backlight off
00106     clearRAM();   // clear RAM to ensure specified current consumption
00107     // send command to ensure we are in basic mode
00108     sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_BASIC_MODE);
00109     // clear the display
00110     sendCommand(CMD_DC_CLEAR_DISPLAY);
00111     // enter the extended mode and power down
00112     sendCommand(0x20 | CMD_FS_POWER_DOWN_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_EXTENDED_MODE);
00113     // small delay and then turn off the power pin
00114     wait_ms(10);
00115 
00116     // if we are powering the LCD using the GPIO then make it low to turn off
00117     if (_pwr != NULL) {
00118         _pwr->write(0);  // turn off power
00119     }
00120 
00121 }
00122 
00123 // function to change LED backlight brightness
00124 void N5110::setBrightness(float brightness)
00125 {
00126     // check whether brightness is within range
00127     if (brightness < 0.0f)
00128         brightness = 0.0f;
00129     if (brightness > 1.0f)
00130         brightness = 1.0f;
00131     // set PWM duty cycle
00132     _led->write(brightness);
00133 }
00134 
00135 
00136 // pulse the active low reset line
00137 void N5110::reset()
00138 {
00139     _rst->write(0);  // reset the LCD
00140     _rst->write(1);
00141 }
00142 
00143 // function to initialise SPI peripheral
00144 void N5110::initSPI()
00145 {
00146     _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
00147     _spi->frequency(4000000);  // maximum of screen is 4 MHz
00148 }
00149 
00150 // send a command to the display
00151 void N5110::sendCommand(unsigned char command)
00152 {
00153     _dc->write(0);  // set DC low for command
00154     _sce->write(0); // set CE low to begin frame
00155     _spi->write(command);  // send command
00156     _dc->write(1);  // turn back to data by default
00157     _sce->write(1); // set CE high to end frame (expected for transmission of single byte)
00158 }
00159 
00160 // send data to the display at the current XY address
00161 // dc is set to 1 (i.e. data) after sending a command and so should
00162 // be the default mode.
00163 void N5110::sendData(unsigned char data)
00164 {
00165     _sce->write(0);   // set CE low to begin frame
00166     _spi->write(data);
00167     _sce->write(1);  // set CE high to end frame (expected for transmission of single byte)
00168 }
00169 
00170 // this function writes 0 to the 504 bytes to clear the RAM
00171 void N5110::clearRAM()
00172 {
00173     _sce->write(0);  //set CE low to begin frame
00174     for(int i = 0; i < WIDTH * HEIGHT; i++) { // 48 x 84 bits = 504 bytes
00175         _spi->write(0x00);  // send 0's
00176     }
00177     _sce->write(1); // set CE high to end frame
00178 }
00179 
00180 // function to set the XY address in RAM for subsequenct data write
00181 void N5110::setXYAddress(unsigned int const x,
00182                          unsigned int const y)
00183 {
00184     if (x<WIDTH && y<HEIGHT) {  // check within range
00185         sendCommand(0x80 | x);  // send addresses to display with relevant mask
00186         sendCommand(0x40 | y);
00187     }
00188 }
00189 
00190 // These functions are used to set, clear and get the value of pixels in the display
00191 // Pixels are addressed in the range of 0 to 47 (y) and 0 to 83 (x).  The refresh()
00192 // function must be called after set and clear in order to update the display
00193 void N5110::setPixel(unsigned int const x,
00194                      unsigned int const y)
00195 {
00196     if (x<WIDTH && y<HEIGHT) {  // check within range
00197         // calculate bank and shift 1 to required position in the data byte
00198         buffer[x][y/8] |= (1 << y%8);
00199     }
00200 }
00201 void N5110::setPixel(unsigned int const x,
00202                      unsigned int const y,
00203                      bool const         state)
00204 {
00205     if (x<WIDTH && y<HEIGHT) {  // check within range
00206         // calculate bank and shift 1 to required position in the data byte
00207         if(state) buffer[x][y/8] |= (1 << y%8);
00208         else      buffer[x][y/8] &= ~(1 << y%8);
00209     }
00210 }
00211 
00212 void N5110::clearPixel(unsigned int const x,
00213                        unsigned int const y)
00214 {
00215     if (x<WIDTH && y<HEIGHT) {  // check within range
00216         // calculate bank and shift 1 to required position (using bit clear)
00217         buffer[x][y/8] &= ~(1 << y%8);
00218     }
00219 }
00220 
00221 int N5110::getPixel(unsigned int const x,
00222                     unsigned int const y) const
00223 {
00224     if (x<WIDTH && y<HEIGHT) {  // check within range
00225         // return relevant bank and mask required bit
00226 
00227         int pixel = (int) buffer[x][y/8] & (1 << y%8);
00228 
00229         if (pixel)
00230             return 1;
00231         else
00232             return 0;
00233     }
00234 
00235     return 0;
00236 
00237 }
00238 
00239 // function to refresh the display
00240 void N5110::refresh()
00241 {
00242     setXYAddress(0,0);  // important to set address back to 0,0 before refreshing display
00243     // address auto increments after printing string, so buffer[0][0] will not coincide
00244     // with top-left pixel after priting string
00245 
00246     _sce->write(0);  //set CE low to begin frame
00247 
00248     for(int j = 0; j < BANKS; j++) {  // be careful to use correct order (j,i) for horizontal addressing
00249         for(int i = 0; i < WIDTH; i++) {
00250             _spi->write(buffer[i][j]);  // send buffer
00251         }
00252     }
00253     _sce->write(1); // set CE high to end frame
00254 
00255 }
00256 
00257 // fills the buffer with random bytes.  Can be used to test the display.
00258 // The rand() function isn't seeded so it probably creates the same pattern everytime
00259 void N5110::randomiseBuffer()
00260 {
00261     int i,j;
00262     for(j = 0; j < BANKS; j++) {  // be careful to use correct order (j,i) for horizontal addressing
00263         for(i = 0; i < WIDTH; i++) {
00264             buffer[i][j] = rand()%256;  // generate random byte
00265         }
00266     }
00267 
00268 }
00269 
00270 // function to print 5x7 font
00271 void N5110::printChar(char const          c,
00272                       unsigned int const  x,
00273                       unsigned int const  y)
00274 {
00275     if (y<BANKS) {  // check if printing in range of y banks
00276 
00277         for (int i = 0; i < 5 ; i++ ) {
00278             int pixel_x = x+i;
00279             if (pixel_x > WIDTH-1)  // ensure pixel isn't outside the buffer size (0 - 83)
00280                 break;
00281             buffer[pixel_x][y] = font5x7[(c - 32)*5 + i];
00282             // array is offset by 32 relative to ASCII, each character is 5 pixels wide
00283         }
00284 
00285     }
00286 }
00287 
00288 // function to print string at specified position
00289 void N5110::printString(const char         *str,
00290                         unsigned int const  x,
00291                         unsigned int const  y)
00292 {
00293     if (y<BANKS) {  // check if printing in range of y banks
00294 
00295         int n = 0 ; // counter for number of characters in string
00296         // loop through string and print character
00297         while(*str) {
00298 
00299             // writes the character bitmap data to the buffer, so that
00300             // text and pixels can be displayed at the same time
00301             for (int i = 0; i < 5 ; i++ ) {
00302                 int pixel_x = x+i+n*6;
00303                 if (pixel_x > WIDTH-1) // ensure pixel isn't outside the buffer size (0 - 83)
00304                     break;
00305                 buffer[pixel_x][y] = font5x7[(*str - 32)*5 + i];
00306             }
00307             str++;  // go to next character in string
00308             n++;    // increment index
00309         }
00310     }
00311 }
00312 
00313 // function to clear the screen buffer
00314 void N5110::clear()
00315 {
00316     memset(buffer,0,sizeof(buffer));
00317 }
00318 
00319 // function to plot array on display
00320 void N5110::plotArray(float const array[])
00321 {
00322     for (int i=0; i<WIDTH; i++) {  // loop through array
00323         // elements are normalised from 0.0 to 1.0, so multiply
00324         // by 47 to convert to pixel range, and subtract from 47
00325         // since top-left is 0,0 in the display geometry
00326         setPixel(i,47 - int(array[i]*47.0f));
00327     }
00328 
00329 }
00330 
00331 // function to draw circle
00332 void N5110:: drawCircle(unsigned int const x0,
00333                         unsigned int const y0,
00334                         unsigned int const radius,
00335                         FillType const     fill)
00336 {
00337     // from http://en.wikipedia.org/wiki/Midpoint_circle_algorithm
00338     int x = radius;
00339     int y = 0;
00340     int radiusError = 1-x;
00341 
00342     while(x >= y) {
00343 
00344         // if transparent, just draw outline
00345         if (fill == FILL_TRANSPARENT) {
00346             setPixel( x + x0,  y + y0);
00347             setPixel(-x + x0,  y + y0);
00348             setPixel( y + x0,  x + y0);
00349             setPixel(-y + x0,  x + y0);
00350             setPixel(-y + x0, -x + y0);
00351             setPixel( y + x0, -x + y0);
00352             setPixel( x + x0, -y + y0);
00353             setPixel(-x + x0, -y + y0);
00354         } else {  // drawing filled circle, so draw lines between points at same y value
00355 
00356             int type = (fill==FILL_BLACK) ? 1:0;  // black or white fill
00357 
00358             drawLine(x+x0,y+y0,-x+x0,y+y0,type);
00359             drawLine(y+x0,x+y0,-y+x0,x+y0,type);
00360             drawLine(y+x0,-x+y0,-y+x0,-x+y0,type);
00361             drawLine(x+x0,-y+y0,-x+x0,-y+y0,type);
00362         }
00363 
00364         y++;
00365         if (radiusError<0) {
00366             radiusError += 2 * y + 1;
00367         } else {
00368             x--;
00369             radiusError += 2 * (y - x) + 1;
00370         }
00371     }
00372 
00373 }
00374 
00375 void N5110::drawLine(unsigned int const x0,
00376                      unsigned int const y0,
00377                      unsigned int const x1,
00378                      unsigned int const y1,
00379                      unsigned int const type)
00380 {
00381     int y_range = y1-y0;  // calc range of y and x
00382     int x_range = x1-x0;
00383     int start,stop,step;
00384 
00385     // if dotted line, set step to 2, else step is 1
00386     step = (type==2) ? 2:1;
00387 
00388     // make sure we loop over the largest range to get the most pixels on the display
00389     // for instance, if drawing a vertical line (x_range = 0), we need to loop down the y pixels
00390     // or else we'll only end up with 1 pixel in the x column
00391     if ( abs(x_range) > abs(y_range) ) {
00392 
00393         // ensure we loop from smallest to largest or else for-loop won't run as expected
00394         start = x1>x0 ? x0:x1;
00395         stop =  x1>x0 ? x1:x0;
00396 
00397         // loop between x pixels
00398         for (int x = start; x<= stop ; x+=step) {
00399             // do linear interpolation
00400             int y = y0 + (y1-y0)*(x-x0)/(x1-x0);
00401 
00402             if (type == 0)   // if 'white' line, turn off pixel
00403                 clearPixel(x,y);
00404             else
00405                 setPixel(x,y);  // else if 'black' or 'dotted' turn on pixel
00406         }
00407     } else {
00408 
00409         // ensure we loop from smallest to largest or else for-loop won't run as expected
00410         start = y1>y0 ? y0:y1;
00411         stop =  y1>y0 ? y1:y0;
00412 
00413         for (int y = start; y<= stop ; y+=step) {
00414             // do linear interpolation
00415             int x = x0 + (x1-x0)*(y-y0)/(y1-y0);
00416 
00417             if (type == 0)   // if 'white' line, turn off pixel
00418                 clearPixel(x,y);
00419             else
00420                 setPixel(x,y);  // else if 'black' or 'dotted' turn on pixel
00421 
00422         }
00423     }
00424 
00425 }
00426 
00427 void N5110::drawRect(unsigned int const x0,
00428                      unsigned int const y0,
00429                      unsigned int const width,
00430                      unsigned int const height,
00431                      FillType const     fill)
00432 {
00433     if (fill == FILL_TRANSPARENT) { // transparent, just outline
00434         drawLine(x0,y0,x0+(width-1),y0,1);  // top
00435         drawLine(x0,y0+(height-1),x0+(width-1),y0+(height-1),1);  // bottom
00436         drawLine(x0,y0,x0,y0+(height-1),1);  // left
00437         drawLine(x0+(width-1),y0,x0+(width-1),y0+(height-1),1);  // right
00438     } else { // filled rectangle
00439         int type = (fill==FILL_BLACK) ? 1:0;  // black or white fill
00440         for (int y = y0; y<y0+height; y++) {  // loop through rows of rectangle
00441             drawLine(x0,y,x0+(width-1),y,type);  // draw line across screen
00442         }
00443     }
00444 }