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Altera_Forum
Honored Contributor I
935 Views

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

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?:(
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1 Reply
Altera_Forum
Honored Contributor I
30 Views

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