N5110.cpp

00001 /**
00002 @file N5110.cpp
00003 
00004 @brief Member functions implementations
00005 
00006 */
00007 #include "mbed.h"
00008 #include "N5110.h"
00009 #include "SWSPI.h"
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     spi = new SWSPI(mosiPin,PTC0,sclkPin); // create new SPI instance and initialise
00016     
00017     initSPI();    
00018     
00019     // set up pins as required
00020     led = new PwmOut(ledPin);
00021     pwr = new DigitalOut(pwrPin);
00022     sce = new DigitalOut(scePin);
00023     rst = new DigitalOut(rstPin);
00024     dc = new DigitalOut(dcPin);
00025 
00026 }
00027 
00028 // initialise function - powers up and sends the initialisation commands
00029 void N5110::init()
00030 {
00031     turnOn();     // power up
00032     wait_ms(10);  // small delay seems to prevent spurious pixels during mbed reset
00033     reset();      // reset LCD - must be done within 100 ms
00034 
00035     // function set - extended
00036     sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_EXTENDED_MODE);
00037     // Don't completely understand these parameters - they seem to work as they are
00038     // Consult the datasheet if you need to change them
00039     sendCommand(CMD_VOP_7V38);    // operating voltage - these values are from Chris Yan's Library
00040     sendCommand(CMD_TC_TEMP_2);   // temperature control
00041     sendCommand(CMD_BI_MUX_48);   // bias
00042 
00043     // function set - basic
00044     sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_BASIC_MODE);
00045     normalMode();  // normal video mode by default
00046     sendCommand(CMD_DC_NORMAL_MODE);  // black on white
00047 
00048     // RAM is undefined at power-up so clear
00049     clearRAM();
00050 
00051 }
00052  
00053 // sets normal video mode (black on white) 
00054 void N5110::normalMode() {
00055      sendCommand(CMD_DC_NORMAL_MODE);  
00056    
00057 }
00058 
00059 // sets normal video mode (white on black) 
00060 void N5110::inverseMode() {
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 model
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->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
00114 
00115     spi->frequency(4000000);  // maximum of screen is 4 MHz
00116 }
00117 
00118 // send a command to the display
00119 void N5110::sendCommand(unsigned char command)
00120 {
00121     dc->write(0);  // set DC low for command
00122     sce->write(0); // set CE low to begin frame
00123     spi->write(command);  // send command
00124     dc->write(1);  // turn back to data by default
00125     sce->write(1); // set CE high to end frame (expected for transmission of single byte)
00126 
00127 }
00128 
00129 // send data to the display at the current XY address
00130 // dc is set to 1 (i.e. data) after sending a command and so should
00131 // be the default mode.
00132 void N5110::sendData(unsigned char data)
00133 {
00134     sce->write(0);   // set CE low to begin frame
00135     spi->write(data);
00136     sce->write(1);  // set CE high to end frame (expected for transmission of single byte)
00137 }
00138 
00139 // this function writes 0 to the 504 bytes to clear the RAM
00140 void N5110::clearRAM()
00141 {
00142     int i;
00143     sce->write(0);  //set CE low to begin frame
00144     for(i = 0; i < 504; i++) { // 48 x 84 bits = 504 bytes
00145         spi->write(0x00);  // send 0's
00146     }
00147     sce->write(1); // set CE high to end frame
00148 
00149 }
00150 
00151 // function to set the XY address in RAM for subsequenct data write 
00152 void N5110::setXYAddress(int x, int y)
00153 {
00154     // check whether address is in range
00155     if (x > 83)
00156         x=83;
00157     if (y > 5)
00158         y=5;
00159     if (x < 0)
00160         x=0;
00161     if (y < 0)
00162         y=0;
00163 
00164     sendCommand(0x80 | x);  // send addresses to display with relevant mask
00165     sendCommand(0x40 | y);
00166 }
00167 
00168 // These functions are used to set, clear and get the value of pixels in the display
00169 // Pixels are addressed in the range of 0 to 47 (y) and 0 to 83 (x).  The refresh()
00170 // function must be called after set and clear in order to update the display
00171 void N5110::setPixel(int x, int y)
00172 {
00173     // calculate bank and shift 1 to required position in the data byte
00174     buffer[x][y/8] |= (1 << y%8);
00175 }
00176 
00177 void N5110::clearPixel(int x, int y)
00178 {
00179     // calculate bank and shift 1 to required position (using bit clear)
00180     buffer[x][y/8] &= ~(1 << y%8);
00181 }
00182 
00183 unsigned char N5110::getPixel(int x, int y)
00184 {
00185     // return relevant bank and mask required bit
00186     return buffer[x][y/8] & (1 << y%8);
00187 
00188 }
00189 
00190 // function to refresh the display
00191 void N5110::refresh()
00192 {
00193     int i,j;
00194     sce->write(0);  //set CE low to begin frame
00195 
00196     for(j = 0; j < 6; j++) {  // be careful to use correct order (j,i) for horizontal addressing
00197         for(i = 0; i < 84; i++) {
00198             spi->write(buffer[i][j]);  // send buffer
00199         }
00200     }
00201     sce->write(1); // set CE high to end frame
00202 
00203 }
00204 
00205 // fills the buffer with random bytes.  Can be used to test the display.
00206 // The rand() function isn't seeded so it probably creates the same pattern everytime
00207 void N5110::randomiseBuffer()
00208 {
00209     int i,j;
00210     for(j = 0; j < 6; j++) {  // be careful to use correct order (j,i) for horizontal addressing
00211         for(i = 0; i < 84; i++) {
00212             buffer[i][j] = rand()%256;  // generate random byte
00213         }
00214     }
00215 
00216 }
00217 
00218 // function to print 5x7 font
00219 void N5110::printChar(char c)
00220 {
00221     int i;
00222     // loop through 5 columns
00223     for (i = 0; i < 5 ; i++ ) {
00224         sendData(font5x7[(c - 32)*5 + i]);
00225         // array is offset by 32 relative to ASCII, each character is 5 pixels wide
00226         // the X address is automatically incremented after each data write
00227     }
00228     sendData(0); // send an empty byte to introduce space between characters
00229 
00230 }
00231 
00232 // function to print string at specified position
00233 void N5110::printString(const char * str,int x,int y)
00234 {
00235     int n = 0 ; // counter for number of characters in string
00236     // loop through string and print character
00237     while(*str) {
00238 
00239         setXYAddress(x+6*n,y);  // leave 1 pixel (6 = 5 + 1) between each character
00240         printChar(*str);   // print the char - can probably so *str++ and remove next line
00241         str++;  // go to next character in string
00242         n++;    // increment index
00243     }
00244 
00245 }
00246 
00247 // function to clear the screen
00248 void N5110::clear()
00249 {
00250     clearBuffer();  // clear the buffer then call the refresh function
00251     refresh();
00252 }
00253 
00254 // function to clear the buffer
00255 void N5110::clearBuffer()
00256 {
00257     int i,j;
00258     for (i=0; i<84; i++) {  // loop through the banks and set the buffer to 0
00259         for (j=0; j<6; j++) {
00260             buffer[i][j]=0;
00261         }
00262     }
00263 }