lcd16x2 data lines with shifting bits

[embedded_galaxy]

hi,

i am working on 16x2 lcd with 4bit mode on pic18f. my connections are as follows :

• RS -RA5
• E - RA4
• D4 - RA3
• D5 - RA2
• D6 - RA1
• D7 - RA0

so my shifting bits are as follows :

	/* First  nibble */
	E_BIT_HIGH; // E to HIGH
	udelay(2);
	// Write data
	LATA = ((LATA & 0x0F) | ((cmd & 0xF0)));

	/* Second nibble */
	// E to HIGH
	LCD_E_BIT_HIGH;
	udelay(2);
	// Write data
	LATA = ((LATA & 0x0F) | (cmd &0x0F)>>4);

is the right way?
is shifting of bits are ok with my data lines connections(D4-D7,RA3-RA0)?

my other configuration for lcd is OK(code is work fine with different data line connections).

is D0-D3 must connected to gnd?

ASAP


thanks

 

[amit.kumar11]

Hi,

is LATA is your data to be send to LCD?

if yes then in your code you are only sending lower 4 bits (LATA & 0x0F).

you can try like this:

low |= (Data&(0x0F));
temp |= (Data >> 4);
high |= temp;
LcdSend(high);
LcdSend(low);

Amit

 

[embedded_galaxy]

thanks for your reply ,

but i am sending command to both lower and higher nibble.

normally lcd is connected to suppose :


RS -RA5
E - RA4
D4 - RA0
D5 - RA1
D6 - RA2
D7 - RA3

but my hardware have following connections :


RS -RA5
E - RA4
D4 - RA3
D5 - RA2
D6 - RA1
D7 - RA0

is there anything different shifting sequence is required?

 

[andre_luis]

is there anything different shifting sequence is required?

You can find on the web several implementations of bit reversing functions, such as:

• https://www.edaboard.com/threads/221765/#post943637
• https://www.edaboard.com/threads/191928/#post803421