Problem in LCD display in PIC 16f876 with 16x2 lcd display

[arup]

pic16f876 lcd

Dear Sir,

I am using 16x2 lcd module (HY-1602F6 printed on LCD MODULE PCB) with PIC16F876A.I am using PORTB.My connection is as follows:
EN -> RB3
RS -> RB2
R/W - > gnd(i want only write operation)

DB7......DB4(LCD data pin 11 to 14) -> PB7...PB4
Other LCD pins are as usual.
Crystal : 20MHz

After executing lcd routine :

My lcd display is not what i wanted to.I have seen only block of black characters.

Same lcd code(with little change i.e sending data with lower port bits) i have tested for other board where control lines were(RS,EN) from PORTA and DATA LINES were RD3...RD0. and crystal 4MHz And it's working perfectly OK.

I have attached the lcd code for review.Pls can anybody give me solution to this issue??
init_LCD() -> lcd initialization routine
putch() -> writting one char on lcd.this calls another routine called
lcd_write()
attached files are in .txt format - init.txt and lcd.txt

rgds,

Arup

 

[PiCS]

pic16f876 + lcd

void LCD_CONTROL(void){
        LCD_EN = 1;
        asm("nop");
        asm("nop");
        asm("nop");
        asm("nop");
        LCD_EN = 0;
}

for 4Mhz signal EN = 4uS
for 20Mhz signal EN = 0.8uS

 

[arup]

16f876

hello,

in the following code....
for 4MHz .....i have omitted L1....L4
only for 20MHz those 4 lines are included.

void LCD_CONTROL(void){
LCD_EN = 1;
asm("nop"); ...............L1
asm("nop"); ...............L2
asm("nop"); ...............L3
asm("nop"); ...............L4
LCD_EN = 0;
}

arup

 

[arup]

pic lcd not displaying

the issue is settled now.It was because of low voltage ICSP programming mode.It was not allowing RB3 to be gen purpose I/O and i was using RB3 as EN signal of lcd.Now i got rid of this my high voltage pgmm.. mode.



thanks

Arup