Go Down

Topic: silly me!! need lcd help (Read 341 times) previous topic - next topic


well i went ahead and made a pcb and soldered an lcd , 16x2 , to it so basically all the wiring is set in stone
and lately ive been wanting to learn how to do things without using other peoples libraries just so that i may learn how things really work behind the curtains

okay like i said my wiring is set in stone so keep that in mind...

unfortunately  i never used an lcd before so i just counted how many connections i needed and stuck them all over the microcontroller

the wiring is:

Enable :                PINC5
ReadWrite :          PIND2
RegisterSelect       PIND3

DataLines 4 - 7      PortC Pins 4 - 1

and a pot from ground to 5v and wiper to the contrast pin

Code: [Select]

* DevBoardLCD.c
* Created: 8/12/2013 2:31:39 AM
*  Author: eddiea6987

#define F_CPU 16000000
#include <avr/io.h>
#include <util/delay.h>

#define enable PINC5 //when writting to lcd data is transfered only on the high to low transition
#define readWrite PIND2 //read write :low to write commands or high to read
#define registerSelect PIND3 //register select : low = commands : high = character

//PORTC    0 0 0 [ 0 0 0 0 ] 0
//the above shows my data lines on port c
void flipEnable(void);
void portCReset();
int main(void)

DDRD |= (1<<registerSelect | 1<<readWrite) ; //set controls to output since i will only be writing to them
DDRC = 0b11111111; //set all of port c to out put since its my data lines and enable pin

PORTC &= ~(1<<enable); //set enable low
PORTD &= ~(1<<readWrite | 1<<registerSelect); //set readwrite to low to write to lcd , and set register select to low to send command
_delay_ms(2000);//delay to let lcd  stabalize..probably too long of a delay but its ok

//send 3 commands of 0x30 to let the lcd start up properly in 8 bit mode  /////////
portCReset(); //make sure all ports on c are cleared

//PORTC    0 0 0 [ 0 0 1 1 ] 0
PORTC |= (1<<PINC1 | 1<<PINC2);//since my data lines dont correspond exactly to the 4 lower pins on port c, but rather pins 4-1  this is how i have to do it
//equivilant of 0x30

PORTC |= (1<<PINC2 | 1<<PINC1);  // do it again

PORTC |= 1<<PINC2 | 1<<PINC1 ; //and one more time

//PORTC    0 0 0 [ 1 0 0 0 ] 0      now set to 4 bit mode, these are the high bits of the byte
PORTC |= 1<<PINC2 ;

//PORTC    0 0 0 [ 1 0 0 0 ] 0
PORTC |= 1<<PINC4 | 1<<PINC3; //send command 1100 to set to two line mode and to enable display , these are the 4 lower bits
_delay_ms(2); // should be in 4 bit mode now...theoretiaclly


//test A
PORTD |= 1<<registerSelect; // set register select high to send character
        portCReset(); // let me clear the data lines just to be safe

//let me send capital "P" 01010000
// so the 4 high bits are 0101
//which on my ports c would be PORTC    0 0 0 [ 0 1 0 1 ] 0
PORTC |= 1<<PINC1 | 1<<PINC3 ;

    portCReset(); // since this clears the port , the data lines are now low and i can send the 4 lower bits which are 0's anyways
_delay_ms(5000); //just delaying to see if anything happens
// i get all black boxes on on the top line , which i read somewhere it means it is not initialized..


void portCReset()
PORTC = 0B00000000;

void flipEnable()
PORTC |= (1<<enable);//toggle the enable pin so that data can be transfgered on falling edge
PORTC &= ~(1<<enable);
portCReset(); // reset the data lines


I could print the Arduino logo on a box of cereal and sell it as "Arduin-O's"


And the question is?


PS I think you need some desoldering braid.


Go Up

Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

via Egeo 16
Torino, 10131