This is file "LCD-lite.c".
//============================================================================== // Copyright (c) 2005-2010, Isaac Marino Bavaresco // All rights reserved. // // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are met: // * Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // * Neither the name of the author nor the // names of its contributors may be used to endorse or promote products // derived from this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE AUTHOR ''AS IS'' AND ANY // EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE // DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY // DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES // (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; // LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND // ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. //============================================================================== // isaacbavaresco@yahoo.com.br //============================================================================== // Set TAB width to 4 characters //============================================================================== #include "LCDcfg-lite.h" //============================================================================== //============================================================================== //============================================================================== //============================================================================== //============================================================================== #if defined USE_READ_PIN && defined DETECT_FAILURE // Flag to indicate that the display is defective. unsigned char displayfailed = 0; #endif // defined USE_READ_PIN && defined DETECT_FAILURE //============================================================================== #define LCDWriteCmd(c) LCDWrite((c),0) #define LCDWriteData(c) LCDWrite((c),1) #define CMD_CLEAR_DISPLAY 0x01 #define CMD_SET_DDRAM_ADDRESS 0x80 //============================================================================== // Writes a character or command to the display. // Arguments: // c The character or command to be written // di Type of write: 0 = command, 1 = character static void LCDWrite( unsigned char c, unsigned char di ) { // Variable to save the interrupts state at function entry. DeclareIntSaveVar( Aux ); #if defined USE_READ_PIN unsigned char s; #if defined DETECT_FAILURE unsigned short n = NUMBER_OF_READS_TIMEOUT; // The display has failed previously... if( displayfailed ) // ... so we will not even try to access it return; #endif // defined DETECT_FAILURE #endif // defined USE_READ_PIN SaveInterruptsState( Aux ); #if defined USE_READ_PIN // Repeat while bit BUSY == 1 do { RestoreInterruptsState( Aux ); // At this point a pending interrupt may be serviced, so we don't // block the system for too long. On return, no assumption is // made about the state of the LCD interface pins, an interrupt // routine may change the value or direction of any pin, except // of the ENABLE pin. DisableInterrupts(); SetDataPortAsInputs(); // Set READ/!WRITE pin as read (1) SetRWAsRead(); // Set DATA/!INSTRUCTION pin as instruction (0) SetDIAsInstruction(); // Effectivate the data transfer. SetEAsEnabled(); // Wait for the minimum 'tHIGH'. Delay500ns(); // Read the status byte (only high nibble if in 4-bit mode). ReadDataPortValue( s ); // Low half of the trasfer cycle. SetEAsDisabled(); // Wait for the minimum 'tLOW'. Delay500ns(); #if defined USE_FOUR_BIT_INTERFACE // When using a 4-bit interface we need to do a dummy read // Effectivate the data transfer. SetEAsEnabled(); // Wait for the minimum 'tHIGH'. Delay500ns(); // Low half of the trasfer cycle. SetEAsDisabled(); // Wait for the minimum 'tLOW'. Delay500ns(); #endif // defined USE_FOUR_BIT_INTERFACE // Set READ/!WRITE pin as write (0) SetRWAsWrite(); } #if !defined DETECT_FAILURE // Repeat until the BUSY bit is zero while( s & 0x80 ); #else // !defined DETECT_FAILURE // Repeat until the BUSY bit is zero or until the maximum number of repetitions. while(( s & 0x80 ) && ( --n != 0u )); // We tried the maximum number of times... if( n == 0u ) // ... so we flag the display as failed displayfailed = 1; #endif // !defined DETECT_FAILURE #else // defined USE_READ_PIN DisableInterrupts(); #endif // defined USE_READ_PIN //-------------------------------------------------------------------------- // Now we may send the data. //-------------------------------------------------------------------------- // Set READ/!WRITE pin as write (0) SetRWAsWrite(); // Set DATA/!INSTRUCTION pin as data (1). SetDIValue( di ); // The data (only high nibble if in 4-bit mode) is output to the data port. SetDataPortValue( c ); SetDataPortAsOutputs(); // Effectivate the data transfer. SetEAsEnabled(); // Wait for the minimum 'tHIGH'. Delay500ns(); // Low half of the trasfer cycle. SetEAsDisabled(); // Wait for the minimum 'tLOW'. Delay500ns(); #if defined USE_FOUR_BIT_INTERFACE // The low nibble is output to the data port. SetDataPortValueLow( c ); // Effectivate the data transfer. SetEAsEnabled(); // Wait for the minimum 'tHIGH'. Delay500ns(); // Low half of the trasfer cycle. SetEAsDisabled(); // Wait for the minimum 'tLOW'. Delay500ns(); #endif // defined USE_FOUR_BIT_INTERFACE SetDataPortAsInputs(); RestoreInterruptsState( Aux ); #if !defined USE_READ_PIN // If we are not reading the busy flag, then we must wait at least for // the worst-case execution time before any other command ca be executed. // This write is a "clear screen" or a "home cursor" command... if( di == 0 && c <= 3 ) // ... that takes up to 1.52ms to execute. Delay1520us(); // For all other writes... else // ... the execution time is no more than 37us. Delay37us(); #endif // !defined USE_READ_PIN } //============================================================================== // Reads one data byte from the LCD. #if defined USE_READ_PIN static unsigned char LCDReadData( void ) { // Variable to save the interrupts state at function entry. DeclareIntSaveVar( Aux ); // Variable to temporarily hold the value read. unsigned char s; #if defined DETECT_FAILURE // Variable to count the number of busy flag reads before an error is signaled. unsigned short n = NUMBER_OF_READS_TIMEOUT; // If the display failed previously... if( displayfailed ) // ... we are not using it until some routine clears the error flag. return 0x00; #endif // defined DETECT_FAILURE SaveInterruptsState( Aux ); // Repeat while busy flag == 1 do { RestoreInterruptsState( Aux ); // At this point a pending interrupt may be serviced, so we don't // block the system for too long. On return, no assumption is // made about the state of the LCD interface pins, an interrupt // routine may change the value or direction of any pin, except // of the ENABLE pin. DisableInterrupts(); SetDataPortAsInputs(); // Set the READ/!WRITE pin as read (1) SetRWAsRead(); // Set DATA/!INSTRUCTION pin as instruction (0) SetDIAsInstruction(); // Effectivate the data transfer. SetEAsEnabled(); // Wait for the minimum 'tHIGH'. Delay500ns(); // Read the status byte (only high nibble if in 4-bit mode). ReadDataPortValue( s ); // Low half of the trasfer cycle. SetEAsDisabled(); // Wait for the minimum 'tLOW'. Delay500ns(); #if defined USE_FOUR_BIT_INTERFACE // When using a 4-bit interface we need to do a dummy read // Effectivate the data transfer. SetEAsEnabled(); // Wait for the minimum 'tHIGH'. Delay500ns(); // Low half of the trasfer cycle. SetEAsDisabled(); // Wait for the minimum 'tLOW'. Delay500ns(); #endif // defined USE_FOUR_BIT_INTERFACE // Set READ/!WRITE pin as write (0) SetRWAsWrite(); } // Test the LCD's BUSY flag. #if !defined DETECT_FAILURE while( s & 0x80 ); #else // !defined DETECT_FAILURE while(( s & 0x80 ) && ( --n != 0u )); if( n == 0u ) displayfailed = 1; #endif // !defined DETECT_FAILURE //-------------------------------------------------------------------------- // Now we can read the data. //-------------------------------------------------------------------------- // Set READ/!WRITE pin as read (1) SetRWAsRead(); // Set DATA/!INSTRUCTION pin as data (1). SetDIAsData(); // Effectivate the data transfer. SetEAsEnabled(); // Wait for the minimum 'tHIGH'. Delay500ns(); // Read the data byte (only high nibble if in 4-bit mode). ReadDataPortValue( s ); // Low half of the trasfer cycle. SetEAsDisabled(); // Wait for the minimum 'tLOW'. Delay500ns(); #if defined USE_FOUR_BIT_INTERFACE // Effectivate the data transfer. SetEAsEnabled(); // Wait for the minimum 'tHIGH'. Delay500ns(); // Read the data byte (low nibble only). ReadDataPortValueLow( s ); // Low half of the trasfer cycle. SetEAsDisabled(); // Wait for the minimum 'tLOW'. Delay500ns(); #endif // defined USE_FOUR_BIT_INTERFACE // Set READ/!WRITE pin as write (0) SetRWAsWrite(); RestoreInterruptsState( Aux ); // Return the read data. return s; } #endif // defined USE_READ_PIN //============================================================================== //============================================================================== //============================================================================== //============================================================================== // // // Hardware-independent part // // //============================================================================== //============================================================================== //============================================================================== //============================================================================== //============================================================================== // Current coordinates of the cursor. static unsigned char cursorx = 0, cursory = 0; // Number of columns and lines of the screen. static unsigned char maxx = INITIAL_MAXX, maxy = INITIAL_MAXY; //============================================================================== unsigned char getmaxx( void ) { return maxx; } //============================================================================== unsigned char getmaxy( void ) { return maxy; } //============================================================================== unsigned char getcursorx( void ) { return cursorx + 1; } //============================================================================== unsigned char getcursory( void ) { return cursory + 1; } //============================================================================== void clrscr( void ) { // interruptstate_t Aux; // // SaveInterruptsState( Aux ); // DisableInterrupts(); // Locate the cursor at the top-left corner of the screen cursorx = 0; cursory = 0; // Send the clear screen command to the LCD controller LCDWriteCmd( CMD_CLEAR_DISPLAY ); // RestoreInterruptsState( Aux ); } //============================================================================== void gotoxy( unsigned char x, unsigned char y ) { // interruptstate_t Aux; // // SaveInterruptsState( Aux ); // DisableInterrupts(); // If the coordinates are valid... if( x <= maxx && y <= maxy ) { // If the column is different than zero... if( x != 0u ) // ... change the current column to it. cursorx = x - 1; // If the line is different than zero... if( y != 0u ) // ... change the current line to it. cursory = y - 1; // We need to positon the hardware cursor to the right place. LCDWriteCmd( CMD_SET_DDRAM_ADDRESS | (( cursory << 6 ) & 0x40 ) | ( cursorx & 0x3f ) + ( cursory & 0x02 ? maxx : 0 )); } // RestoreInterruptsState( Aux ); } //============================================================================== // This routine's real name is defined in the file 'LCDcfg-lite.h'. // The name must be chosen to allow the library routines (printf, etc.) to link // to it. // NEW: The redefinable characters 0x01 to 0x06 may be printed directly, but // characters 0x00 and 0x07 conflict with special control codes. They may be // printed by using codes 0x0e and 0x0f, respectively. // This is the best possible solution, because we don't lose neither displayable // nor control characters (characters 8 to 15 are just a shadow of characters 0 // to 7). // Character 0 = '\0' (end of string) // Characters 1 to 6 = special redefinable characters 1 to 6. // Characters 7 to 13 = standard control characters. // Character 14 = printed as redefinable character zero. // Character 15 = printed as redefinable character 7. void LCD_PUTC( char c ) { // interruptstate_t Aux; // // SaveInterruptsState( Aux ); // DisableInterrupts(); switch( c ) { //---------------------------------------------------------------------- // '\a' = BELL case '\a': Beep(); // RestoreInterruptsState( Aux ); return /*0*/; //---------------------------------------------------------------------- // '\b' = BACKSPACE case '\b': // The cursor is not on the first column, ... if( cursorx > 0u ) // ... decrement the column. cursorx--; // The cursor is on the first column but it is not on the first line, ... else if( cursory > 0u ) { // ... position the cursor at the end of the previous line. cursory--; cursorx = maxx - 1; } // The LCD must be updated with the correct cursor coordinates. LCDWriteCmd( 0x80 | (( cursory << 6 ) & 0x40 ) | ( cursorx & 0x0f ) + ( cursory & 0x02 ? maxx : 0 )); // ... finished. // RestoreInterruptsState( Aux ); return /*0*/; //---------------------------------------------------------------------- // '\f' = FORMFEED case '\f': // Clear the screen. // Locate the cursor at the top-left corner of the screen cursorx = 0; cursory = 0; // Send the clear screen command to the LCD controller LCDWriteCmd( CMD_CLEAR_DISPLAY ); // RestoreInterruptsState( Aux ); return /*0*/; //---------------------------------------------------------------------- // '\n' = NEWLINE case '\n': // Return the cursor to the beginning of the line. cursorx = 0; // Fall-through to 'VTAB', to increment the line //---------------------------------------------------------------------- // '\v' = VTAB case '\v': // Increment the line number. cursory++; // Outside the 'switch' we will check if a wrap-around is needed. break; //---------------------------------------------------------------------- // '\r' = CR (carriage return) case '\r': // Return the cursor to the beginning of the line. cursorx = 0; // The LCD must be updated with the correct cursor coordinates. LCDWriteCmd( 0x80 | (( cursory << 6 ) & 0x40 ) | ( cursorx & 0x0f ) + ( cursory & 0x02 ? maxx : 0 )); // Fim // RestoreInterruptsState( Aux ); return /*0*/; //---------------------------------------------------------------------- // Aqui tratamos do caractere tabulação ('\t' = TAB) case '\t': { // We need a temporary variable. unsigned char Temp; // Calculate the column of the next tabulation. Temp = ( cursorx + TAB_WIDTH ) & ~( TAB_WIDTH - 1 ); // The cursor will be beyond the column after the last, ... if( Temp > maxx ) // ... restrict the cursor to the column after the last. Temp = maxx; // Calculate how many spaces must be inserted. Temp -= cursorx; // Advance the column to its final position. cursorx += Temp; // Print as many spaces as needed to reach the final position for( ; Temp; Temp-- ) LCDWriteData( ' ' ); // The cursor ended beyond the last column, ... if( cursorx >= maxx ) { // ... position the cursor to the beginning of the next line. cursorx = 0; cursory++; // Outside the 'switch' we will check if a wrap-around is needed. break; } // The cursor is yet on the same line, we may return right now. // RestoreInterruptsState( Aux ); return /*0*/; } //---------------------------------------------------------------------- // The character 14 (0x0e) will be translated to the redefinable // character 0 (zero). case 14: // Here we subtract 6, in the next case we subtract 8, resulting in zero. c -= 6; // Fall-through. //---------------------------------------------------------------------- // The character 15 (0x0f) will be translated to the redefinable // character 7. case 15: c -= 8; // Fall-through. //---------------------------------------------------------------------- // Here we cope with the printable characters. default: // Print the character. LCDWriteData( c ); // Increment the column. cursorx++; // The cursor ended beyond the last column, ... if( cursorx >= maxx ) { // ... position the cursor to the beginning of the next line. cursorx = 0; cursory++; // Outside the 'switch' we will check if a wrap-around is needed. break; } // The cursor is yet on the same line, we may return right now. // RestoreInterruptsState( Aux ); return /*0*/; } //-------------------------------------------------------------------------- // The cursor is beyond the last line, ... if( cursory >= maxy ) // ... position it on the last line... cursory = 0; // We must position the LCD cursor on the right place. LCDWriteCmd( 0x80 | (( cursory << 6 ) & 0x40 ) | ( cursorx & 0x0f ) + ( cursory & 0x02 ? maxx : 0 )); //-------------------------------------------------------------------------- // RestoreInterruptsState( Aux ); return /*0*/; } //============================================================================== void LCDControlCursor( unsigned char Mode ) { LCDWriteCmd(( Mode & 0x03 ) | 0x0c ); } //============================================================================== void LCDDefineChar( unsigned char Char, const unsigned char *Pattern ) { unsigned char c; LCDWriteCmd((( Char << 3 ) & 0x38 ) | 0x40 ); for( c = 8; c; c-- ) LCDWriteData( *Pattern++ ); LCDWriteCmd( 0x80 | (( cursory << 6 ) & 0x40 ) | ( cursorx & 0x3f ) + ( cursory & 0x02 ? maxx : 0 )); } //============================================================================== void LCDInit( void ) { // Initialize the LCD data interface. // The initial value of the LCD's ENABLE pin is 0 (disabled). SetEAsDisabled(); // The LCD's ENABLE pin is an output. SetEAsOutput(); // The initial value of the LCD's READ/!WRITE pin is 0 (write). SetRWAsWrite(); // The LCD's READ/!WRITE pin is an output. SetRWAsOutput(); // The initial value of the LCD's DATA/!INSTRUCTION pin is 0 (data). SetDIAsInstruction(); // The LCD's DATA/!INSTRUCTION pin is an output. SetDIAsOutput(); // Chip initialization, following data-sheet procedure. // Delay mandated by the data-sheet // "Wait for more than 15 ms after VCC rises to 4.5 V." // or // "Wait for more than 40 ms after VCC rises to 2.7 V." Delay15ms(); // Value to set the LCD interface to 8 bits, irrespective of the real board // interface length. SetDataPortValue( 0x30 ); SetDataPortAsOutputs(); // The command to change the interface to 8 bits must be issued 3 times. // Issue the command (first time). SetEAsEnabled(); // Wait for the minimum 'tHIGH'. Delay500ns(); // Low half of the trasfer cycle. SetEAsDisabled(); // Delay mandated by the data-sheet // "Wait for more than 4.1 ms." Delay4100us(); // Issue the command (second time). SetEAsEnabled(); // Wait for the minimum 'tHIGH'. Delay500ns(); // Low half of the trasfer cycle. SetEAsDisabled(); // Delay mandated by the data-sheet // "Wait for more than 100 µs." Delay100us(); // Issue the command (third time). SetEAsEnabled(); // Wait for the minimum 'tHIGH'. Delay500ns(); // Low half of the trasfer cycle. SetEAsDisabled(); #if !defined USE_READ_PIN // Wait for the execution time. Delay37us(); #endif // !defined USE_READ_PIN // Set the correct interface length #if defined USE_FOUR_BIT_INTERFACE // "Function set (Set interface to be 4 bits long.) Interface is 8 bits in length." LCDWriteCmd( 0x28 ); #else // defined USE_FOUR_BIT_INTERFACE // "Function set (Interface is 8 bits long.)" LCDWriteCmd( 0x38 ); #endif // defined USE_FOUR_BIT_INTERFACE // Turn display on LCDWriteCmd( 0x0c ); // Clear display LCDWriteCmd( CMD_CLEAR_DISPLAY ); } //==============================================================================
file: /Techref/member/IMB-yahoo-J86/lcd-lite.c.htm, 24KB, , updated: 2010/4/28 17:24, local time: 2024/8/15 00:30,
owner: IMB-yahoo-J86,
3.21.97.51:LOG IN
|
©2024 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions? <A HREF="http://techref.massmind.org/Techref/member/IMB-yahoo-J86/lcd-lite.c.htm"> Routines to control a HD44780-based LCD module emulating a tty screen (lite version)</A> |
Did you find what you needed? |