LCD hitachi hc9s12256Dp

[nevi]

hello, I have problem with program. I don't know what is cmd_reg. This program is from one book. But there wasn't explaint it.
#include hc12.h
#include stdio.h
char *msg = "this is a very very very long string in the desert storm";
void putc2lcd(char ch);
void puts2lcd(char *ptr);
void lcd_init();

void main(void)
{
lcd_init();
puts2lcd(msg);
asm("swi");
}
void lcd_init()
{
while(cmd_reg & 0x80); /* wait until LCD is ready */
cmd_reg = 0x3C; /* set 4 x 20 display */
while(cmd_reg & 0x80);
cmd_reg = 0x0f; /* display and cursor on */
while(cmd_reg & 0x80);
cmd_reg = 0x14; /* display and cursor on */
while(cmd_reg & 0x80);
cmd_reg = 0x01; /* display and cursor on */
while(cmd_reg & 0x80);
}
void puts2lcd (char *ptr)
{
while (*ptr) {
putc2lcd (*ptr);
ptr++;
}
} Do you know please. What should be cmd_reg? And how i can do that? Thank you very much. I sorry for my english.

Message Edited by nevi on 2008-03-29 11:29 PM

Message Edited by nevi on 2008-03-29 11:30 PM

[peg]

Hello and welcome to the forums nevi,

This code looks like it is for a 4x20 character LCD module based on a Hitachi HD44780 controller.
Therefore cmd_reg would be the 8-bit port which connects to the data port of the LCD module.
They are using reads of the busy flag in between initialisation writes instead of delays and it is unclear how the  modules R/W input is being controlled.
Also you have not shown us the putc2lcd function.

It is a good idea to use a code box (the SRC button) to display example code as it will look neater.

[JimDon]

I have some sample code, but it uses 4 bit mode.
Quite often interfaces do this so that only 6 bits are used.
There are 4 data bits, a command/data line, and a strobe. The R/W line is always set to write.
This controller can do 4-bit or 8-bit transfers.

Can you confirm the connection of your interface?
What board is it?