Seven Segment Display Scrolling

[sonar_abhi]

I am coding SSD display using 2 cascaded shift registers. I am using a mikroC for PIC compiler. I can display a static sequence of numbers upto 4 digits with my code

#define SHIFT_CLOCK PORTB.F1    //Clock Connection of 74HC595 SSD Driver
#define SHIFT_LATCH PORTB.F3    //Latch Connection of 74HC595 SSD Driver
#define SHIFT_DATA PORTB.F2    //Data Connection of 74HC595 SSD Driver

char array4[4] = {6, 91, 79, 102};           //Display 1234 on SSD
char digit[4] = {0xFE, 0xFD, 0xFB, 0xF7};   //Switch on the SSD digits one by one

char i,j,temp,flag1,flag2;

void InitTimer0()
{
 OPTION_REG     = 0x86;
 TMR0           = 6;
 INTCON         = 0xA0;
}

void latch595()
{
 SHIFT_LATCH = 1;
 Delay_us(1);
 SHIFT_LATCH = 0;
}

void shiftdata595(unsigned char _shiftdata)
{
 int i;
 unsigned char temp;
 temp = _shiftdata;
 i=8;
 while (i>0)
 {
  if (temp.F7==0)
   {
    SHIFT_DATA = 0;
   }
   else
   {
    SHIFT_DATA = 1;
   }
   temp = temp<<1;
   SHIFT_CLOCK = 1;
   SHIFT_CLOCK = 0;
   i--;
 }
}

void Interrupt()
{
 if (TMR0IF_bit)
 {
  TMR0IF_bit  = 0;
  TMR0        = 6;
  flag1 = 1;
  flag2 = 1;
 }
}

void main()
{
 TRISB = 0;
 TRISC.F1 = 1;
 InitTimer0();
 while (1)
 {
  if (PORTC.F1==0)
  {
   if (flag2==1)
   {
    shiftdata595(digit[i]);
    i++;
    if(i==4)
    {
     i=0;
    }
    if (flag1==1)
    {
     shiftdata595(array4[j]);
     latch595();
     j++;
     if (j==4)
     {
      j=0;
     }
    }
   }
  }
  else if(PORTC.F1==1)
  {
   shiftdata595(0);
   shiftdata595(0);
   latch595();
  }
 }
}

If I add more digits to the array4[], say upto 9, I will need to scroll the digits to the left sequentially. I tried shifting the array by

temp = array4[0];
for (n=1; n<8; n++)
{
 array4[j-1] = array[j];
}
array[9] = temp;

I hoped that this code will left shift the array and the display will scroll, but all I am getting is a jumbled up display. If I add a delay, I can see that the numbers are getting displayed but without scrolling.

Is the basic algorithm faulty or can it be used by modifying the code?

 

[Ian Rogers]

If your original code displays 1234... Then all seems to be working.. So!!

You need data for all the numbers then an array to hold the data before running it to the SSD..

That second piece of code doesn't add up? where does n and j come in to it..

temp = array4[0];
for (n=1; n<8; n++)
{
 array4[j-1] = array[j];
}
array[9] = temp;

That should read like this...

temp = array4[0];
for (n=1; n<8; n++)
{
 array4[n-1] = array4[n];
}
array4[9] = temp;