Timing help / LCD

jonathan_abbati — Tue, 31 May 2011 00:46:40 GMT

Hello Friends!

I am working with the MC9S12DG128 and attempting to utilize the onboard timer defined as TCNT. I am attempting to program the HD44780 LCD which is integrated on my EVALH1 board from technological arts. I have been following various online examples for 4 bit initialization and I believe that timing is the issue which I am having right now. My questions would have to be:

1) Is there a better timing method that you could think of?

2) Within code warrior is there a way that I can test if my delay is delaying to the proper time, I cannot seem to see where it shows the clock cycles.

Here is my timer & main code given in that order code:

Timer:

void timer_init(void)
{
TSCR1 = 0x80; // SET TEN (TIMER ENABLE BIT)
TSCR2 = 0x03; // SET PRESCALER TO DIVIDE BUS CLOCK BY 8 WHICH GIVES US A PERIOD OF 1uS
}

    void timer_wait1us(unsigned short z)
    {
      unsigned short start1; // NOTE THAT THE FIRST VALUE OF THE FOR LOOP HAS BEEN LEFT EMPTY SO WE MAY DEFINE IT WITHIN THE PROGRAM
        for(;z>0;z--)
        {

          start1 = TCNT;
          while ((TCNT - start1) <=1) // -start1 IS USED TO SET THE TIMER BACK TO 0 BEFORE WE READ FROM IT
          {}

        }
    }



        void timer_wait1ms (unsigned short x)
        {
          unsigned short start2;
            for(;x>0;x--)
            {
              start2 = TCNT;
              while ((TCNT - start2) <= 1000)
              {}

}
}

Main:

#include <hidef.h> /* common defines and macros */
#include "derivative.h" /* derivative-specific definitions */
#include "Timer.h"

void toggle_enable(void);
void outcmd(unsigned char command);
void clear (void);
void output(unsigned char letter);

void main(void) {
unsigned long z;
DDRS = 0xFF;
DDRE = 0xFF;

timer_init();

timer_wait1ms(20);
outcmd(0x30);
timer_wait1ms(5);
outcmd(0x30);
timer_wait1us(160);
outcmd(0x30);
timer_wait1us(160);
outcmd(0x20);
timer_wait1ms(5);
outcmd(0x28);
timer_wait1ms(5);

outcmd(0x08);
timer_wait1ms(5);

clear();

outcmd(0x0E);
timer_wait1ms(50);

// CONSISTANT UNTIL HERE

outcmd(0x06);
timer_wait1ms(50);
outcmd(0x0C);
timer_wait1ms(50);

output(0x48);

EnableInterrupts;

for(; {
_FEED_COP(); /* feeds the dog */
} /* loop forever */
/* please make sure that you never leave main */
}

void toggle_enable(void){

PORTE_BIT4 = 1;
timer_wait1us(2);
PORTE_BIT4 = 0;
timer_wait1ms(5);
}

void outcmd(unsigned char command){

PTS = 0xF0 & command;
toggle_enable();
PTS = 0xF0 & (command<<4);
toggle_enable();
}

void clear(void){

outcmd(0x01);
timer_wait1ms(5);
outcmd(0x02);
timer_wait1ms(5);

}

void output(unsigned char letter){

PORTE_BIT7 = 1;
toggle_enable();
PTS = 0xF0 & letter;
toggle_enable();
PTS = 0xF0 & (letter<<4);
toggle_enable();
}

Thank you so very much for your time I greatly appreciate anything you may be able to help me with!

Re: Timing help / LCD

jonathan_abbati — Thu, 02 Jun 2011 00:53:35 GMT

Within the FCS ( full chip simulation) you can find time testing capabilities for your microcontroller based off of your bus clock. I have found that the easiest way to make a proper delay was through using for loops and creating a formula to find out how long each will be.

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