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Altera_Forum
Honored Contributor I
985 Views

How to Initialize Char LCD using PIO (De0-Nano)

Hello to the whole forum, this is my very first thread so please be kind with me(= 

 

I'm trying to drive a char LCD using my de0 nano but no results yet.. 

 

My lcd is a 5v unit but since I need just to write to it I guess it wont be a problem, except for a bit weak logic 1 but according to data sheet it should work. 

 

I tried the altera university core for 16 x 2 char LCD but since I must keep the reduced drivers enabled this seems not the right option to save memory, anyway this core was able to properly initialize the LCD so I must have made some coding/timing error. 

 

In my new implemntation I drive it with 2 separate PIO, one for RS, R/W, En + one for Data. 

 

The PIO_LCD_COMMAND drives the 3bit output bus (msb is RS, RW, lsb is En), then the PIO_LCD_DATA drives the lcd bidirectional data bus. 

 

Here's the LCD data sheet if it may help: http://www.farnell.com/datasheets/2051086.pdf?_ga=1.268795697.1932054068.1473273391 

 

Here below I've attached my initialization code, I hope someone might help! Much thanks guys :D 

 

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_LCD_DATA_BASE, ALTERA_AVALON_PIO_DIRECTION_OUTPUT); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x00); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE,0b000); 

 

 

 

 

usleep(16000); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE,0b001); 

usleep(100); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x30); 

usleep(100); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE,0b000); 

usleep(4500); 

 

 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE,0b001); 

usleep(100); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x30); 

usleep(100); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE,0b000); 

usleep(200); 

 

 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE,0b001); 

usleep(100); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x30); 

usleep(100); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE,0b000); 

usleep(200); 

 

 

 

 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE,0b001); 

usleep(100); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x38); 

usleep(100); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE,0b000); 

usleep(200); 

 

 

 

 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE,0b001); 

usleep(100); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x08); 

usleep(100); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE,0b000); 

usleep(200); 

 

 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE,0b001); 

usleep(100); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x01); 

usleep(100); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE,0b000); 

usleep(200); 

 

 

 

 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE,0b001); 

usleep(100); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x06); 

usleep(100); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE,0b000); 

 

usleep(200); 

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2 Replies
Altera_Forum
Honored Contributor I
48 Views

Hi I've been able to initialize it correctly. 

 

I didn't set the biport output direction for all data pins. 

 

No I fixed it: 

 

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_LCD_DATA_BASE , 0b11111111); 

 

Anyway I try to print some char after the initialization but no result, here's the code I used to print a char: 

 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x80); 

usleep(1); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b001); 

usleep(2); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b000); 

usleep(200); 

 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x41); 

usleep(1); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b101); 

usleep(2); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b100); 

usleep(200); 

 

I take some wide timing since I wanted to be sure the unit has time to do its internal operation.
Altera_Forum
Honored Contributor I
48 Views

Everything solved, now I can print char and do stuff. 

 

The second issue was caused by wrong timing. 

 

The Clear Display command is quite slow and it take 1.52ms to be done, so I Changed usleep(2000). 

 

As I said I've taken super wide delays since I wanted to avoid timing issue. 

 

This is my working/corrected code, I hope it may help someone: 

 

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_LCD_DATA_BASE, 0b11111111); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x00); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b000); 

 

 

usleep(16000); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x38); 

usleep(1); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b001); 

usleep(2); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b000); 

usleep(4500); 

 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x38); 

usleep(1); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b001); 

usleep(2); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b000); 

usleep(200); 

 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x38); 

usleep(1); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b001); 

usleep(2); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b000); 

usleep(200); 

 

 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x38); 

usleep(1); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b001); 

usleep(2); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b000); 

usleep(200); 

 

 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x0E); 

usleep(1); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b001); 

usleep(2); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b000); 

usleep(200); 

 

 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x01); 

usleep(1); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b001); 

usleep(2); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b000); 

usleep(2000); 

 

 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x06); 

usleep(1); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b001); 

usleep(2); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b000); 

usleep(200); 

 

 

//data to test lcd 

 

 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_DATA_BASE, 0x41); // A 

usleep(1); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b101); 

usleep(2); 

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LCD_COMMAND_BASE, 0b100); 

usleep(2);
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