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| who have sorcecode of LCD in 8 bit mode. Please post me sour |
 Posted: Mon Aug 16, 2004 8:21 pm |
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| who have sorcecode of LCD in 8 bit mode. Please post me sourcecode. because my sourcecode is not stable. it have 1 line. sometime it have 2 line. i use 16f877 and lcd 16*2 char. thank you for your help |
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Guest
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| Posted: Tue Aug 17, 2004 10:11 am |
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| The address of the second line's first char is 64 regardless of the number of chars/line. Don't forget to clear display content before sending new text etc. |
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Ttelmah
Guest
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| Re: who have sorcecode of LCD in 8 bit mode. Please post me |
| Posted: Tue Aug 17, 2004 10:48 am |
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| Anonymous wrote: | | who have sorcecode of LCD in 8 bit mode. Please post me sourcecode. because my sourcecode is not stable. it have 1 line. sometime it have 2 line. i use 16f877 and lcd 16*2 char. thank you for your help |
There is not really much to it!.
Using PortB for the 8biit data, and three bits defined as 'RW', 'RS', and 'EN' for the control, with portB set to 'fastio':
| Code: |
/* These are the values to send to the LCD for special control/setup */
#DEFINE BS 0x08 /* code to backspace */
#DEFINE EMD 0x1E /* program to default entry mode */
#DEFINE CLS 0x12 /* clear screen */
#DEFINE FLINE 0x80 /* move to location */
#DEFINE CON 0x1B /* enable cursor */
#DEFINE COFF 0x1A /* disable cursor */
#DEFINE FSET 0x1F /* set to 2 lines etc. */
#DEFINE DISON 0x1D /* code to switch on display */
#DEFINE DISOFF 0x1C /* code to disable display */
#DEFINE HOME 0x80 /* code to goto home */
#DEFINE LASTTO 0x9F /* Last 'goto' command */
#DEFINE SLINE 0x90 /* code to goto start second line */
#DEFINE CR 0x0C /* carriage return */
#DEFINE LF 0x0A /* line feed */
#DEFINE CLEOL 0x19 /* clear to EOL */
#DEFINE CGW 0x17 /* write to CG RAM */
#DEFINE DW 0x18 /* write to normal RAM */
/* These are the LCD control lines */
#DEFINE EN PIN_C0
#DEFINE RS PIN_C2
#DEFINE RW PIN_C1
void dctl(unsigned int chr)
{
/* this is the code to put one char (chr) to the control port on the LCD */
/* to do this, I need to raise the 'strobe', but leave RS low */
portb=chr;
output_low(RW);
delay_us(1);
output_high(EN);
delay_us(2);
output_low(EN);
}
void ddat(unsigned int chr)
{
/* as above for the data port on the LCD */
portb=chr;
output_low(RW);
output_high(RS);
delay_us(1);
output_high(EN);
delay_us(2);
output_low(EN);
output_low(RS);
}
int checkflag(void) {
int ipval;
SET_TRIS_B(0xFF);
OUTPUT_LOW(RS);
OUTPUT_HIGH(RW);
OUTPUT_HIGH(EN);
delay_us(5);
pval=portb;
OUTPUT_LOW(EN);
OUTPUT_LOW(RW);
SET_TRIS_B(0);
return(ipval & 0x80);
}
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I have a 'parser', which uses:
| Code: |
static int DRAM=true;
static unsigned int dcon = 0x0f;
while (checkflag()) ;
if (chr<0x20)
{
/* here I have a control character */
/* This has the most complex layout, requiring character translation... */
switch (chr) {
case 0:
case 1:
case 2:
case 3:
case 4:
case 5:
case 6:
case 7:
ddat(chr); /* send CGRAM display character */
break;
case BS:
/* This is the 'bs' character */
dctl(0x10); /* This shifts left one character */
break;
/* Note that this does not provide the proper 'bs' function. The
input code has to substitute 'bs, space, bs' to get the required
display */
case CLS:
/* CLS */
dctl(1);
break;
case COFF:
/* cursor off */
bit_clear(dcon,1);
bit_clear(dcon,0);
dctl(dcon);
break;
case CON:
bit_set(dcon,1);
bit_set(dcon,0);
dctl(dcon);
break;
case DISOFF:
/* display off */
bit_clear(dcon,2);
dctl(dcon);
break;
case DISON:
bit_set(dcon,2);
dctl(dcon);
break;
case EMD:
/* EMD command (increment, no shift) */
dctl(6);
break;
case FSET:
/* function set */
dctl(0x38);
break;
case CGW:
/* This sets a flag, so that the _next_ address write switches to CGW */
DRAM=FALSE;
break;
case DW:
DRAM=true;
break;
default:
break;
}
}
else if (chr>=HOME && chr<=(LASTTO+1))
{
/* Here I have a 'goto' character */
/* Here the low five bits of the character are the required address */
/* I also have to check whether CGRAM, or DDRAM is required */
if (DRAM)
{
if (chr>=0x90)
dctl(chr+0x30);
else
{
while (true) {
dctl(chr);
while (checkflag()) ;
/* Here I check that address has updated */
SET_TRIS_B(0xFF);
OUTPUT_LOW(RS);
OUTPUT_HIGH(RW);
OUTPUT_HIGH(EN);
delay_us(5);
ipval=portb;
OUTPUT_LOW(EN);
if (ipval == (chr & 0x7F)) {
OUTPUT_LOW(RW);
SET_TRIS_B(0);
break;
}
OUTPUT_LOW(RW);
SET_TRIS_B(0);
}
}
}
else
{
/* Here I want to talk to CGRAM */
dctl(chr-0x40);
}
}
else
{
/* here a normal text character */
ddat(chr);
}
}
}
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You'll have to count the brackets, since it is cut out of a larger subroutine. The initialisation sequence, is then FSET,FSET,FSET,FSET, DISOFF,DISON,EMD,FLINE.
Best Wishes |
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treitmey
Joined: 23 Jan 2004
Posts: 1094
Location: Appleton,WI USA
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