N5110.cpp

00001 /**
00002 @file N5110.cpp
00003 
00004 @brief Member functions implementations
00005 
00006 */
00007 #include "mbed.h"
00008 #include "N5110.h"
00009 
00010 
00011 N5110::N5110(PinName pwrPin, PinName scePin, PinName rstPin, PinName dcPin, PinName mosiPin, PinName sclkPin, PinName ledPin)
00012 {
00013 
00014     spi = new SPI(mosiPin,NC,sclkPin); // create new SPI instance and initialise
00015     initSPI();
00016 
00017     // set up pins as required
00018     led = new PwmOut(ledPin);
00019     pwr = new DigitalOut(pwrPin);
00020     sce = new DigitalOut(scePin);
00021     rst = new DigitalOut(rstPin);
00022     dc = new DigitalOut(dcPin);
00023 
00024 }
00025 
00026 // initialise function - powers up and sends the initialisation commands
00027 void N5110::init()
00028 {
00029     turnOn();     // power up
00030     wait_ms(10);  // small delay seems to prevent spurious pixels during mbed reset
00031     reset();      // reset LCD - must be done within 100 ms
00032 
00033     // function set - extended
00034     sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_EXTENDED_MODE);
00035     // Don't completely understand these parameters - they seem to work as they are
00036     // Consult the datasheet if you need to change them
00037     sendCommand(CMD_VOP_7V38);    // operating voltage - these values are from Chris Yan's Library
00038     sendCommand(CMD_TC_TEMP_2);   // temperature control
00039     sendCommand(CMD_BI_MUX_48);   // bias
00040 
00041     // function set - basic
00042     sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_BASIC_MODE);
00043     normalMode();  // normal video mode by default
00044     sendCommand(CMD_DC_NORMAL_MODE);  // black on white
00045 
00046     // RAM is undefined at power-up so clear
00047     clearRAM();
00048 
00049 }
00050 
00051 // sets normal video mode (black on white)
00052 void N5110::normalMode()
00053 {
00054     sendCommand(CMD_DC_NORMAL_MODE);
00055 
00056 }
00057 
00058 // sets normal video mode (white on black)
00059 void N5110::inverseMode()
00060 {
00061     sendCommand(CMD_DC_INVERT_VIDEO);
00062 }
00063 
00064 // function to power up the LCD and backlight
00065 void N5110::turnOn()
00066 {
00067     // set brightness of LED - 0.0 to 1.0 - default is 50%
00068     setBrightness(0.5);
00069     pwr->write(1);  // apply power
00070 }
00071 
00072 // function to power down LCD
00073 void N5110::turnOff()
00074 {
00075     setBrightness(0.0);  // turn backlight off
00076     clearRAM();   // clear RAM to ensure specified current consumption
00077     // send command to ensure we are in basic mode
00078     sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_BASIC_MODE);
00079     // clear the display
00080     sendCommand(CMD_DC_CLEAR_DISPLAY);
00081     // enter the extended mode and power down
00082     sendCommand(0x20 | CMD_FS_POWER_DOWN_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_EXTENDED_MODE);
00083     // small delay and then turn off the power pin
00084     wait_ms(10);
00085     pwr->write(0);
00086 
00087 }
00088 
00089 // function to change LED backlight brightness
00090 void N5110::setBrightness(float brightness)
00091 {
00092     // check whether brightness is within range
00093     if (brightness < 0.0)
00094         brightness = 0.0;
00095     if (brightness > 1.0)
00096         brightness = 1.0;
00097     // set PWM duty cycle
00098     led->write(brightness);
00099 }
00100 
00101 
00102 // pulse the active low reset line
00103 void N5110::reset()
00104 {
00105     rst->write(0);  // reset the LCD
00106     rst->write(1);
00107 }
00108 
00109 // function to initialise SPI peripheral
00110 void N5110::initSPI()
00111 {
00112     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
00113     spi->frequency(4000000);  // maximum of screen is 4 MHz
00114 }
00115 
00116 // send a command to the display
00117 void N5110::sendCommand(unsigned char command)
00118 {
00119     dc->write(0);  // set DC low for command
00120     sce->write(0); // set CE low to begin frame
00121     spi->write(command);  // send command
00122     dc->write(1);  // turn back to data by default
00123     sce->write(1); // set CE high to end frame (expected for transmission of single byte)
00124 
00125 }
00126 
00127 // send data to the display at the current XY address
00128 // dc is set to 1 (i.e. data) after sending a command and so should
00129 // be the default mode.
00130 void N5110::sendData(unsigned char data)
00131 {
00132     sce->write(0);   // set CE low to begin frame
00133     spi->write(data);
00134     sce->write(1);  // set CE high to end frame (expected for transmission of single byte)
00135 }
00136 
00137 // this function writes 0 to the 504 bytes to clear the RAM
00138 void N5110::clearRAM()
00139 {
00140     int i;
00141     sce->write(0);  //set CE low to begin frame
00142     for(i = 0; i < WIDTH * HEIGHT; i++) { // 48 x 84 bits = 504 bytes
00143         spi->write(0x00);  // send 0's
00144     }
00145     sce->write(1); // set CE high to end frame
00146 
00147 }
00148 
00149 // function to set the XY address in RAM for subsequenct data write
00150 void N5110::setXYAddress(int x, int y)
00151 {
00152     if (x>=0 && x<WIDTH && y>=0 && y<HEIGHT) {  // check within range
00153         sendCommand(0x80 | x);  // send addresses to display with relevant mask
00154         sendCommand(0x40 | y);
00155     }
00156 }
00157 
00158 // These functions are used to set, clear and get the value of pixels in the display
00159 // Pixels are addressed in the range of 0 to 47 (y) and 0 to 83 (x).  The refresh()
00160 // function must be called after set and clear in order to update the display
00161 void N5110::setPixel(int x, int y)
00162 {
00163     if (x>=0 && x<WIDTH && y>=0 && y<HEIGHT) {  // check within range
00164         // calculate bank and shift 1 to required position in the data byte
00165         buffer[x][y/8] |= (1 << y%8);
00166     }
00167 }
00168 
00169 void N5110::clearPixel(int x, int y)
00170 {
00171     if (x>=0 && x<WIDTH && y>=0 && y<HEIGHT) {  // check within range
00172         // calculate bank and shift 1 to required position (using bit clear)
00173         buffer[x][y/8] &= ~(1 << y%8);
00174     }
00175 }
00176 
00177 int N5110::getPixel(int x, int y)
00178 {
00179     if (x>=0 && x<WIDTH && y>=0 && y<HEIGHT) {  // check within range
00180         // return relevant bank and mask required bit
00181         return (int) buffer[x][y/8] & (1 << y%8);
00182         // note this does not necessarily return 1 - a non-zero number represents a pixel
00183     } else {
00184         return 0;
00185     }
00186 }
00187 
00188 // function to refresh the display
00189 void N5110::refresh()
00190 {
00191     int i,j;
00192 
00193     setXYAddress(0,0);  // important to set address back to 0,0 before refreshing display
00194     // address auto increments after printing string, so buffer[0][0] will not coincide
00195     // with top-left pixel after priting string
00196 
00197     sce->write(0);  //set CE low to begin frame
00198 
00199     for(j = 0; j < BANKS; j++) {  // be careful to use correct order (j,i) for horizontal addressing
00200         for(i = 0; i < WIDTH; i++) {
00201             spi->write(buffer[i][j]);  // send buffer
00202         }
00203     }
00204     sce->write(1); // set CE high to end frame
00205 
00206 }
00207 
00208 // fills the buffer with random bytes.  Can be used to test the display.
00209 // The rand() function isn't seeded so it probably creates the same pattern everytime
00210 void N5110::randomiseBuffer()
00211 {
00212     int i,j;
00213     for(j = 0; j < BANKS; j++) {  // be careful to use correct order (j,i) for horizontal addressing
00214         for(i = 0; i < WIDTH; i++) {
00215             buffer[i][j] = rand()%256;  // generate random byte
00216         }
00217     }
00218 
00219 }
00220 
00221 // function to print 5x7 font
00222 void N5110::printChar(char c,int x,int y)
00223 {
00224     if (y>=0 && y<BANKS) {  // check if printing in range of y banks
00225 
00226         for (int i = 0; i < 5 ; i++ ) {
00227             int pixel_x = x+i;
00228             if (pixel_x > WIDTH-1)  // ensure pixel isn't outside the buffer size (0 - 83)
00229                 break;
00230             buffer[pixel_x][y] = font5x7[(c - 32)*5 + i];
00231             // array is offset by 32 relative to ASCII, each character is 5 pixels wide
00232         }
00233 
00234         refresh();  // this sends the buffer to the display and sets address (cursor) back to 0,0
00235     }
00236 }
00237 
00238 // function to print string at specified position
00239 void N5110::printString(const char * str,int x,int y)
00240 {
00241     if (y>=0 && y<BANKS) {  // check if printing in range of y banks
00242 
00243         int n = 0 ; // counter for number of characters in string
00244         // loop through string and print character
00245         while(*str) {
00246 
00247             // writes the character bitmap data to the buffer, so that
00248             // text and pixels can be displayed at the same time
00249             for (int i = 0; i < 5 ; i++ ) {
00250                 int pixel_x = x+i+n*6;
00251                 if (pixel_x > WIDTH-1) // ensure pixel isn't outside the buffer size (0 - 83)
00252                     break;
00253                 buffer[pixel_x][y] = font5x7[(*str - 32)*5 + i];
00254             }
00255 
00256             str++;  // go to next character in string
00257 
00258             n++;    // increment index
00259 
00260         }
00261 
00262         refresh();  // this sends the buffer to the display and sets address (cursor) back to 0,0
00263     }
00264 }
00265 
00266 // function to clear the screen
00267 void N5110::clear()
00268 {
00269     clearBuffer();  // clear the buffer then call the refresh function
00270     refresh();
00271 }
00272 
00273 // function to clear the buffer
00274 void N5110::clearBuffer()
00275 {
00276     int i,j;
00277     for (i=0; i<WIDTH; i++) {  // loop through the banks and set the buffer to 0
00278         for (j=0; j<BANKS; j++) {
00279             buffer[i][j]=0;
00280         }
00281     }
00282 }
00283 
00284 // function to plot array on display
00285 void N5110::plotArray(float array[])
00286 {
00287 
00288     int i;
00289 
00290     for (i=0; i<WIDTH; i++) {  // loop through array
00291         // elements are normalised from 0.0 to 1.0, so multiply
00292         // by 47 to convert to pixel range, and subtract from 47
00293         // since top-left is 0,0 in the display geometry
00294         setPixel(i,47 - int(array[i]*47.0));
00295     }
00296 
00297     refresh();
00298 
00299 }
00300 
00301 // function to draw circle
00302 void N5110:: drawCircle(int x0,int y0,int radius,int fill)
00303 {
00304     // from http://en.wikipedia.org/wiki/Midpoint_circle_algorithm
00305     int x = radius;
00306     int y = 0;
00307     int radiusError = 1-x;
00308 
00309     while(x >= y) {
00310 
00311         // if transparent, just draw outline
00312         if (fill == 0) {
00313             setPixel( x + x0,  y + y0);
00314             setPixel(-x + x0,  y + y0);
00315             setPixel( y + x0,  x + y0);
00316             setPixel(-y + x0,  x + y0);
00317             setPixel(-y + x0, -x + y0);
00318             setPixel( y + x0, -x + y0);
00319             setPixel( x + x0, -y + y0);
00320             setPixel(-x + x0, -y + y0);
00321         } else {  // drawing filled circle, so draw lines between points at same y value
00322 
00323             int type = (fill==1) ? 1:0;  // black or white fill
00324 
00325             drawLine(x+x0,y+y0,-x+x0,y+y0,type);
00326             drawLine(y+x0,x+y0,-y+x0,x+y0,type);
00327             drawLine(y+x0,-x+y0,-y+x0,-x+y0,type);
00328             drawLine(x+x0,-y+y0,-x+x0,-y+y0,type);
00329         }
00330 
00331 
00332         y++;
00333         if (radiusError<0) {
00334             radiusError += 2 * y + 1;
00335         } else {
00336             x--;
00337             radiusError += 2 * (y - x) + 1;
00338         }
00339     }
00340 
00341 }
00342 
00343 void N5110::drawLine(int x0,int y0,int x1,int y1,int type)
00344 {
00345     int y_range = y1-y0;  // calc range of y and x
00346     int x_range = x1-x0;
00347     int start,stop,step;
00348 
00349     // if dotted line, set step to 2, else step is 1
00350     step = (type==2) ? 2:1;
00351 
00352     // make sure we loop over the largest range to get the most pixels on the display
00353     // for instance, if drawing a vertical line (x_range = 0), we need to loop down the y pixels
00354     // or else we'll only end up with 1 pixel in the x column
00355     if ( abs(x_range) > abs(y_range) ) {
00356 
00357         // ensure we loop from smallest to largest or else for-loop won't run as expected
00358         start = x1>x0 ? x0:x1;
00359         stop =  x1>x0 ? x1:x0;
00360 
00361         // loop between x pixels
00362         for (int x = start; x<= stop ; x+=step) {
00363             // do linear interpolation
00364             int y = y0 + (y1-y0)*(x-x0)/(x1-x0);
00365 
00366             if (type == 0)   // if 'white' line, turn off pixel
00367                 clearPixel(x,y);
00368             else
00369                 setPixel(x,y);  // else if 'black' or 'dotted' turn on pixel
00370         }
00371     } else {
00372 
00373         // ensure we loop from smallest to largest or else for-loop won't run as expected
00374         start = y1>y0 ? y0:y1;
00375         stop =  y1>y0 ? y1:y0;
00376 
00377         for (int y = start; y<= stop ; y+=step) {
00378             // do linear interpolation
00379             int x = x0 + (x1-x0)*(y-y0)/(y1-y0);
00380 
00381             if (type == 0)   // if 'white' line, turn off pixel
00382                 clearPixel(x,y);
00383             else
00384                 setPixel(x,y);  // else if 'black' or 'dotted' turn on pixel
00385 
00386         }
00387     }
00388 
00389 }
00390 
00391 void N5110::drawRect(int x0,int y0,int width,int height,int fill)
00392 {
00393 
00394     if (fill == 0) { // transparent, just outline
00395         drawLine(x0,y0,x0+width,y0,1);  // top
00396         drawLine(x0,y0+height,x0+width,y0+height,1);  // bottom
00397         drawLine(x0,y0,x0,y0+height,1);  // left
00398         drawLine(x0+width,y0,x0+width,y0+height,1);  // right
00399     } else { // filled rectangle
00400         int type = (fill==1) ? 1:0;  // black or white fill
00401         for (int y = y0; y<= y0+height; y++) {  // loop through rows of rectangle
00402             drawLine(x0,y,x0+width,y,type);  // draw line across screen
00403         }
00404     }
00405 
00406 }