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      sendCommand(CMD_DC_NORMAL_MODE);  
00054    
00055 }
00056  
00057 // sets normal video mode (white on black) 
00058 void N5110::inverseMode() {
00059     sendCommand(CMD_DC_INVERT_VIDEO); 
00060 }
00061  
00062 // function to power up the LCD and backlight
00063 void N5110::turnOn()
00064 {
00065     // set brightness of LED - 0.0 to 1.0 - default is 50%
00066     setBrightness(0.5);
00067     pwr->write(1);  // apply power
00068 }
00069  
00070 // function to power down LCD
00071 void N5110::turnOff()
00072 {
00073     setBrightness(0.0);  // turn backlight off
00074     clearRAM();   // clear RAM to ensure specified current consumption
00075     // send command to ensure we are in basic model
00076     sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_BASIC_MODE);
00077     // clear the display
00078     sendCommand(CMD_DC_CLEAR_DISPLAY);
00079     // enter the extended mode and power down
00080     sendCommand(0x20 | CMD_FS_POWER_DOWN_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_EXTENDED_MODE);
00081     // small delay and then turn off the power pin
00082     wait_ms(10);
00083     pwr->write(0);
00084  
00085 }
00086  
00087 // function to change LED backlight brightness
00088 void N5110::setBrightness(float brightness)
00089 {
00090     // check whether brightness is within range
00091     if (brightness < 0.0)
00092         brightness = 0.0;
00093     if (brightness > 1.0)
00094         brightness = 1.0;
00095     // set PWM duty cycle
00096     led->write(brightness);
00097 }
00098  
00099  
00100 // pulse the active low reset line
00101 void N5110::reset()
00102 {
00103     rst->write(0);  // reset the LCD
00104     rst->write(1);
00105 }
00106  
00107 // function to initialise SPI peripheral
00108 void N5110::initSPI()
00109 {
00110     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
00111     spi->frequency(4000000);  // maximum of screen is 4 MHz
00112 }
00113  
00114 // send a command to the display
00115 void N5110::sendCommand(unsigned char command)
00116 {
00117     dc->write(0);  // set DC low for command
00118     sce->write(0); // set CE low to begin frame
00119     spi->write(command);  // send command
00120     dc->write(1);  // turn back to data by default
00121     sce->write(1); // set CE high to end frame (expected for transmission of single byte)
00122  
00123 }
00124  
00125 // send data to the display at the current XY address
00126 // dc is set to 1 (i.e. data) after sending a command and so should
00127 // be the default mode.
00128 void N5110::sendData(unsigned char data)
00129 {
00130     sce->write(0);   // set CE low to begin frame
00131     spi->write(data);
00132     sce->write(1);  // set CE high to end frame (expected for transmission of single byte)
00133 }
00134  
00135 // this function writes 0 to the 504 bytes to clear the RAM
00136 void N5110::clearRAM()
00137 {
00138     int i;
00139     sce->write(0);  //set CE low to begin frame
00140     for(i = 0; i < 504; i++) { // 48 x 84 bits = 504 bytes
00141         spi->write(0x00);  // send 0's
00142     }
00143     sce->write(1); // set CE high to end frame
00144  
00145 }
00146  
00147 // function to set the XY address in RAM for subsequenct data write 
00148 void N5110::setXYAddress(int x, int y)
00149 {
00150     // check whether address is in range
00151     if (x > 83)
00152         x=83;
00153     if (y > 5)
00154         y=5;
00155     if (x < 0)
00156         x=0;
00157     if (y < 0)
00158         y=0;
00159  
00160     sendCommand(0x80 | x);  // send addresses to display with relevant mask
00161     sendCommand(0x40 | y);
00162 }
00163  
00164 // These functions are used to set, clear and get the value of pixels in the display
00165 // Pixels are addressed in the range of 0 to 47 (y) and 0 to 83 (x).  The refresh()
00166 // function must be called after set and clear in order to update the display
00167 void N5110::setPixel(int x, int y)
00168 {
00169     // calculate bank and shift 1 to required position in the data byte
00170     buffer[x][y/8] |= (1 << y%8);
00171 }
00172  
00173 void N5110::clearPixel(int x, int y)
00174 {
00175     // calculate bank and shift 1 to required position (using bit clear)
00176     buffer[x][y/8] &= ~(1 << y%8);
00177 }
00178  
00179 unsigned char N5110::getPixel(int x, int y)
00180 {
00181     // return relevant bank and mask required bit
00182     return buffer[x][y/8] & (1 << y%8);
00183  
00184 }
00185  
00186 // function to refresh the display
00187 void N5110::refresh()
00188 {
00189     int i,j;
00190     sce->write(0);  //set CE low to begin frame
00191  
00192     for(j = 0; j < 6; j++) {  // be careful to use correct order (j,i) for horizontal addressing
00193         for(i = 0; i < 84; i++) {
00194             spi->write(buffer[i][j]);  // send buffer
00195         }
00196     }
00197     sce->write(1); // set CE high to end frame
00198  
00199 }
00200  
00201 // fills the buffer with random bytes.  Can be used to test the display.
00202 // The rand() function isn't seeded so it probably creates the same pattern everytime
00203 void N5110::randomiseBuffer()
00204 {
00205     int i,j;
00206     for(j = 0; j < 6; j++) {  // be careful to use correct order (j,i) for horizontal addressing
00207         for(i = 0; i < 84; i++) {
00208             buffer[i][j] = rand()%256;  // generate random byte
00209         }
00210     }
00211  
00212 }
00213  
00214 // function to print 5x7 font
00215 void N5110::printChar(char c)
00216 {
00217     int i;
00218     // loop through 5 columns
00219     for (i = 0; i < 5 ; i++ ) {
00220         sendData(font5x7[(c - 32)*5 + i]);
00221         // array is offset by 32 relative to ASCII, each character is 5 pixels wide
00222         // the X address is automatically incremented after each data write
00223     }
00224     sendData(0); // send an empty byte to introduce space between characters
00225  
00226 }
00227  
00228 // function to print string at specified position
00229 void N5110::printString(const char * str,int x,int y)
00230 {
00231     int n = 0 ; // counter for number of characters in string
00232     // loop through string and print character
00233     while(*str) {
00234  
00235         setXYAddress(x+6*n,y);  // leave 1 pixel (6 = 5 + 1) between each character
00236         printChar(*str);   // print the char - can probably so *str++ and remove next line
00237         str++;  // go to next character in string
00238         n++;    // increment index
00239     }
00240  
00241 }
00242  
00243 // function to clear the screen
00244 void N5110::clear()
00245 {
00246     clearBuffer();  // clear the buffer then call the refresh function
00247     refresh();
00248 }
00249  
00250 // function to clear the buffer
00251 void N5110::clearBuffer()
00252 {
00253     int i,j;
00254     for (i=0; i<84; i++) {  // loop through the banks and set the buffer to 0
00255         for (j=0; j<6; j++) {
00256             buffer[i][j]=0;
00257         }
00258     }
00259 }