16x2 lcd interface from 8 bits to 4 bits in the hal driver

[Altera_Forum]

Hi everyone, 

 I am trying to use the altera_avalon_lcd_16207 Driver to drive my Lcd and its working fine for me. But when I am trying to work with 4 bits interface using the same altera_avalon_lcd_16207 driver provided by the altera its not working. Find the below think I changed in the same driver.  ________________________________________________________________________________________ line no : 548; file name : altera_avalon_lcd_16207.c ; function name : altera_avalon_lcd_16207_init(); original code : /* Setup interface parameters: 8 bit bus, 2 rows, 5x7 font */ -lcd_write_command(sp, LCD_CMD_FUNCTION_SET | LCD_CMD_8BIT | LCD_CMD_TWO_LINE);  changed code : /* Setup interface parameters: 8 bit bus, 2 rows, 5x7 font */ +lcd_write_command(sp, LCD_CMD_FUNCTION_SET | LCD_CMD_TWO_LINE);  line no : 163 ; file name : altera_avalon_lcd_16207.c;function name : lcd_write_command();  IOWR_ALTERA_AVALON_LCD_16207_COMMAND(base, command); +command = command << 4;  +IOWR_ALTERA_AVALON_LCD_16207_COMMAND(base, command);   line no : 198 ; file name : altera_avalon_lcd_16207.c; function name : lcd_write_data();  IOWR_ALTERA_AVALON_LCD_16207_DATA(base, data); +data = data << 4;  +IOWR_ALTERA_AVALON_LCD_16207_DATA(base, data);   ______________________________________________________________________________________   the above are the changes i done so far in the given HAL driver. but not its not working for me. So plz any one can suggest how i can solve this issue?:(

[Altera_Forum]

Hi everyone, 

 I got the solution for the above one and find the patch for the same.  --- src/altera_avalon_lcd_16207.c 2015-04-23 11:17:46.000000000 +0530 +++ src/altera_avalon_lcd_16207.c 2016-09-06 15:30:57.331296200 +0530 @@ -161,9 +161,11 @@  /* Despite what it says in the datasheet, the LCD isn't ready to accept  * a write immediately after it returns BUSY=0. Wait for 100us more.  */ - usleep(100); + usleep(1000);   - IOWR_ALTERA_AVALON_LCD_16207_COMMAND(base, command); + IOWR_ALTERA_AVALON_LCD_16207_COMMAND(base, ( command & 0xf0 )); + command = command << 4; + IOWR_ALTERA_AVALON_LCD_16207_COMMAND(base, ( command & 0xf0 ));  }    /* --------------------------------------------------------------------- */ @@ -197,7 +199,9 @@  */  usleep(100);   - IOWR_ALTERA_AVALON_LCD_16207_DATA(base, data); + IOWR_ALTERA_AVALON_LCD_16207_DATA(base, ( data & 0xf0 )); + data = data << 4; + IOWR_ALTERA_AVALON_LCD_16207_DATA(base, ( data & 0xf0 ));    sp->address++;  } @@ -577,8 +581,11 @@  usleep(1000);  IOWR_ALTERA_AVALON_LCD_16207_COMMAND(base, LCD_CMD_FUNCTION_SET | LCD_CMD_8BIT);   - /* Setup interface parameters: 8 bit bus, 2 rows, 5x7 font */ - lcd_write_command(sp, LCD_CMD_FUNCTION_SET | LCD_CMD_8BIT | LCD_CMD_TWO_LINE); + /* Setup interface parameters: 4 bit bus */ + lcd_write_command(sp, LCD_CMD_FUNCTION_SET ); + + /* Setup interface parameters: 4 bit bus, 2 rows, 5x7 font */ + lcd_write_command(sp, LCD_CMD_FUNCTION_SET | LCD_CMD_TWO_LINE);    /* Turn display off */  lcd_write_command(sp, LCD_CMD_ONOFF);   Thanks