Simple library for interfacing to Nokia 5110 LCD display (as found on the SparkFun website). Edited to include additional feaatures, such as 2d array loading, multiple screen buffers, and better backlight control
Dependencies: N5110
Fork of N5110 by
Diff: N5110.cpp
- Revision:
- 6:adb79338d40f
- Parent:
- 5:6ea180eef702
- Child:
- 7:3010f24e0a81
--- a/N5110.cpp Sun Jan 26 20:18:45 2014 +0000 +++ b/N5110.cpp Mon Jan 27 18:41:45 2014 +0000 @@ -14,6 +14,7 @@ spi = new SPI(mosiPin,NC,sclkPin); // create new SPI instance and initialise initSPI(); + // set up pins as required led = new PwmOut(ledPin); pwr = new DigitalOut(pwrPin); sce = new DigitalOut(scePin); @@ -22,15 +23,17 @@ } - +// initialise function - powers up and sends the initialisation commands void N5110::init() { - turnOn(); // power up - reset(); // reset LCD - must be done within 100 ms + turnOn(); // power up + wait_ms(10); // small delay seems to prevent spurious pixels during mbed reset + reset(); // reset LCD - must be done within 100 ms // function set - extended sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_EXTENDED_MODE); - + // Don't completely understand these parameters - they seem to work as they are + // Consult the datasheet if you need to change them sendCommand(CMD_VOP_7V38); // operating voltage - these values are from Chris Yan's Library sendCommand(CMD_TC_TEMP_2); // temperature control sendCommand(CMD_BI_MUX_48); // bias @@ -39,7 +42,6 @@ sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_BASIC_MODE); normalMode(); // normal video mode by default sendCommand(CMD_DC_NORMAL_MODE); // black on white - //sendCommand(CMD_DC_INVERT_VIDEO); // white on black // RAM is undefined at power-up so clear clearRAM(); @@ -68,12 +70,16 @@ // function to power down LCD void N5110::turnOff() { - setBrightness(0.0); // turn backlight off clearRAM(); // clear RAM to ensure specified current consumption + // send command to ensure we are in basic model sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_BASIC_MODE); + // clear the display sendCommand(CMD_DC_CLEAR_DISPLAY); + // enter the extended mode and power down sendCommand(0x20 | CMD_FS_POWER_DOWN_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_EXTENDED_MODE); + // small delay and then turn off the power pin + wait_ms(10); pwr->write(0); } @@ -105,6 +111,7 @@ spi->frequency(4000000); // maximum of screen is 4 MHz } +// send a command to the display void N5110::sendCommand(unsigned char command) { dc->write(0); // set DC low for command @@ -115,6 +122,9 @@ } +// send data to the display at the current XY address +// dc is set to 1 (i.e. data) after sending a command and so should +// be the default mode. void N5110::sendData(unsigned char data) { sce->write(0); // set CE low to begin frame @@ -134,9 +144,9 @@ } +// function to set the XY address in RAM for subsequenct data write void N5110::setXYAddress(int x, int y) { - // check whether address is in range if (x > 83) x=83; @@ -151,9 +161,12 @@ sendCommand(0x40 | y); } +// These functions are used to set, clear and get the value of pixels in the display +// Pixels are addressed in the range of 0 to 47 (y) and 0 to 83 (x). The refresh() +// function must be called after set and clear in order to update the display void N5110::setPixel(int x, int y) { - // calculate bank and shift 1 to required position + // calculate bank and shift 1 to required position in the data byte buffer[x][y/8] |= (1 << y%8); } @@ -170,9 +183,9 @@ } -void N5110::refreshDisplay() +// function to refresh the display +void N5110::refresh() { - int i,j; sce->write(0); //set CE low to begin frame @@ -185,11 +198,11 @@ } +// fills the buffer with random bytes. Can be used to test the display. +// The rand() function isn't seeded so it probably creates the same pattern everytime void N5110::randomiseBuffer() { - int i,j; - for(j = 0; j < 6; j++) { // be careful to use correct order (j,i) for horizontal addressing for(i = 0; i < 84; i++) { buffer[i][j] = rand()%256; // generate random byte @@ -201,13 +214,13 @@ // function to print 5x7 font void N5110::printChar(char c) { - + int i; // loop through 5 columns - for (int j = 0; j < 5 ; j++ ) { - sendData(font5x7[(c - 32)*5 + j]); + for (i = 0; i < 5 ; i++ ) { + sendData(font5x7[(c - 32)*5 + i]); // array is offset by 32 relative to ASCII, each character is 5 pixels wide + // the X address is automatically incremented after each data write } - sendData(0); // send an empty byte to introduce space between characters } @@ -220,23 +233,25 @@ while(*str) { setXYAddress(x+6*n,y); // leave 1 pixel (6 = 5 + 1) between each character - printChar(*str); + printChar(*str); // print the char - can probably so *str++ and remove next line str++; // go to next character in string n++; // increment index } } +// function to clear the screen void N5110::clear() { - clearBuffer(); - refreshDisplay(); + clearBuffer(); // clear the buffer then call the refresh function + refresh(); } +// function to clear the buffer void N5110::clearBuffer() { int i,j; - for (i=0; i<84; i++) { + for (i=0; i<84; i++) { // loop through the banks and set the buffer to 0 for (j=0; j<6; j++) { buffer[i][j]=0; }