Updated for mbed: Simple library for interfacing to Nokia 5110 LCD display (as found on the SparkFun website).
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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 }
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