st7920.cpp

00001 #include "st7920.h"
00002 
00003 ST7920::ST7920 (PinName _RS,PinName _RW, PinName _E, PinName DB0, PinName DB1, PinName DB2, PinName DB3, PinName DB4, PinName DB5, PinName DB6, PinName DB7)
00004         : DB(DB0,DB1,DB2,DB3,DB4,DB5,DB6,DB7),RS(_RS), RW(_RW), E(_E) {
00005 
00006     DB.output();
00007     E.write(0);
00008     RS.write(0);
00009     RW.write(0);
00010     InitDisplay();
00011 }
00012 
00013 unsigned int ST7920::ByteReadLCD() {
00014     unsigned int data;
00015 
00016     DB.input();
00017     E.write(1);
00018     data = DB.read();
00019     E.write(0);
00020     DB.output();
00021 
00022     return data;
00023 }
00024 
00025 void ST7920::ByteWriteLCD(unsigned int data) {
00026     DB.output();
00027     E.write(1);
00028     DB.write(data);
00029     E.write(0);
00030 }
00031 
00032 void ST7920::WriteInstruction(unsigned int Command) {
00033     ReadBusyFlag();
00034     RS.write(0);
00035     RW.write(0);
00036     ByteWriteLCD(Command);
00037 }
00038 
00039 void ST7920::WriteRAM(unsigned int data) {
00040     ReadBusyFlag();
00041     RS.write(1);
00042     RW.write(0);
00043     ByteWriteLCD(data);
00044 }
00045 
00046 void ST7920::ReadBusyFlag() {
00047     unsigned char data;
00048 
00049     RS.write(0);
00050     RW.write(1);
00051     while ((data & 0x7F) == BUSY_FLAG_BF) {
00052         data = ByteReadLCD();
00053     }
00054 }
00055 
00056 unsigned int ST7920::Read_AC() {
00057     RS.write(0);
00058     RW.write(1);
00059     return (ByteReadLCD() & 0x7F);
00060 }
00061 
00062 unsigned int ST7920::ReadRAM() {
00063     ReadBusyFlag();
00064     RS.write(1);
00065     RW.write(1);
00066     return ByteReadLCD();
00067 }
00068 
00069 void ST7920::InitDisplay() {
00070     wait_ms(40); // wait 40ms
00071     E.write(0);
00072     WriteInstruction(FUNCTION_SET | DATA_LENGTH_DL); // 8 bits interface, RE=0
00073     wait_us(100); // wait 100us
00074     WriteInstruction(FUNCTION_SET | DATA_LENGTH_DL); // again
00075     wait_us(37); // wait 37us
00076     WriteInstruction(DISPLAY_CONTROL | DISPLAY_ON_D ); // display on
00077     wait_us(100); // wait 100us
00078     WriteInstruction(DISPLAY_CLEAR); // clear display
00079     wait_ms(10); // wait 10ms
00080     WriteInstruction(ENTRY_MODE_SET | INCREASE_DECREASE_ID); // move cursor right
00081     wait_ms(10); // wait 10ms
00082     WriteInstruction(RETURN_HOME);
00083     SetGraphicsMode();
00084 }
00085 
00086 //************************************************************************************************
00087 //public methodes
00088 void ST7920::SetGraphicsMode() {
00089     WriteInstruction(EXTENDED_FUNCTION_SET | DATA_LENGTH_DL);
00090     WriteInstruction(EXTENDED_FUNCTION_SET | DATA_LENGTH_DL | EXTENDED_INSTRUCTION_RE); //RE=1 (Extended funtion set)
00091     WriteInstruction(EXTENDED_FUNCTION_SET | DATA_LENGTH_DL | EXTENDED_INSTRUCTION_RE | GRAPHIC_ON_G);
00092 }
00093 
00094 void ST7920::SetTextMode() {
00095     WriteInstruction(FUNCTION_SET | DATA_LENGTH_DL); // RE=0 (Basic funtion set)
00096 }
00097 
00098 void ST7920::ClearScreen() {
00099     WriteInstruction(FUNCTION_SET | DATA_LENGTH_DL); // RE=0 (Basic funtion set)
00100     WriteInstruction(DISPLAY_CLEAR);
00101 }
00102 
00103 void ST7920::ReturnHome() {
00104     WriteInstruction(FUNCTION_SET | DATA_LENGTH_DL); //RE=0 (Basic funtion set)
00105     WriteInstruction(RETURN_HOME);
00106 }
00107 
00108 void ST7920::Standby() {
00109     WriteInstruction(EXTENDED_FUNCTION_SET | DATA_LENGTH_DL | EXTENDED_INSTRUCTION_RE); //RE=1 (Extended funtion set)
00110     WriteInstruction(STANDBY);
00111 }
00112 
00113 //Basic text functions
00114 void ST7920::DisplayString(int Row,int Column,unsigned char *ptr,int length) {
00115     int i=0;
00116 
00117     switch (Row) {
00118         case 0:
00119             Column|=0x80;
00120             break;
00121         case 1:
00122             Column|=0x90;
00123             break;
00124         case 2:
00125             Column|=0x88;
00126             break;
00127         case 3:
00128             Column|=0x98;
00129             break;
00130         default:
00131             Column=0x80;
00132             break;
00133     }
00134 
00135     if (Column%2!=0) {
00136         Column-=1;
00137         i=1;
00138     }
00139     WriteInstruction((unsigned int)Column);
00140 
00141     if (i==1) {
00142         WriteRAM(' ');
00143     }
00144     for (i=0; i<length; i++) {
00145         WriteRAM((unsigned int)ptr[i]);
00146     }
00147 }
00148 
00149 void ST7920::DisplayChar(int Row,int Column,int inpChr) {
00150     int i=0;
00151 
00152     switch (Row) {
00153         case 0:
00154             Column|=0x80; // SET_DDRAM_ADDRESS
00155             break;
00156         case 1:
00157             Column|=0x90;
00158             break;
00159         case 2:
00160             Column|=0x88;
00161             break;
00162         case 3:
00163             Column|=0x98;
00164             break;
00165         default:
00166             Column=0x80;
00167             break;
00168     }
00169 
00170     if (Column%2!=0) {
00171         Column-=1;
00172         i=1;
00173     }
00174     WriteInstruction((unsigned int)Column);
00175 
00176     if (i==1) {
00177         WriteRAM(' ');
00178     }
00179     WriteRAM((unsigned int)inpChr);
00180 }
00181 
00182 // Graphic functions
00183 void ST7920::FillGDRAM(unsigned char *bitmap) {
00184     unsigned char i, j, k ;
00185 
00186     for ( i = 0 ; i < 2 ; i++ ) {
00187         for ( j = 0 ; j < 32 ; j++ ) {
00188             WriteInstruction(SET_GRAPHIC_RAM_ADDRESS | j) ;
00189             if ( i == 0 ) {
00190                 WriteInstruction(SET_GRAPHIC_RAM_ADDRESS) ;
00191             } else {
00192                 WriteInstruction(SET_GRAPHIC_RAM_ADDRESS | 0x08) ;
00193             }
00194             for ( k = 0 ; k < 16 ; k++ ) {
00195                 WriteRAM( *bitmap++ ) ;
00196             }
00197         }
00198     }
00199 }
00200 
00201 void ST7920::FillGDRAM_Turned(unsigned char *bitmap) {
00202     int i, j, k, m, offset_row, mask ;
00203     unsigned char data;
00204 
00205     for ( i = 0 ; i < 2 ; i++ ) { //upper and lower page
00206         for ( j = 0 ; j < 32 ; j++ ) { //32 lines per page
00207             WriteInstruction(SET_GRAPHIC_RAM_ADDRESS | j) ;
00208             if ( i == 0 ) {
00209                 WriteInstruction(SET_GRAPHIC_RAM_ADDRESS) ;
00210             } else {
00211                 WriteInstruction(SET_GRAPHIC_RAM_ADDRESS | 0x08) ;
00212             }
00213             mask=1<<(j%8); // extract bitnumber
00214             //printf("mask: %d\r\n",mask);
00215             for ( k = 0 ; k < 16 ; k++ ) { //16 bytes per line
00216                 offset_row=((i*32+j)/8)*128 + k*8; //y coordinate/8 = row 0-7 * 128 = byte offset, read 8 bytes
00217                 data=0;
00218                 for (m = 0 ; m < 8 ; m++) { // read 8 bytes from source
00219 
00220                     if ((bitmap[offset_row+m] & mask)) { //pixel = 1
00221                         data|=(128>>m);
00222                     }
00223                 }
00224                 WriteRAM(data) ;
00225             }
00226         }
00227     }
00228 }
00229 
00230 void ST7920::ClearGDRAM() {
00231     unsigned char i, j, k ;
00232 
00233     for ( i = 0 ; i < 2 ; i++ ) {
00234         for ( j = 0 ; j < 32 ; j++ ) {
00235             WriteInstruction(SET_GRAPHIC_RAM_ADDRESS | j) ;
00236             if ( i == 0 ) {
00237                 WriteInstruction(SET_GRAPHIC_RAM_ADDRESS) ;
00238             } else {
00239                 WriteInstruction(SET_GRAPHIC_RAM_ADDRESS | 0x08) ;
00240             }
00241             for ( k = 0 ; k < 16 ; k++ ) {
00242                 WriteRAM(0);
00243             }
00244         }
00245     }
00246 }