I am trying to drive a Digital display using the above schematic. I know how the circuit works, I am just having some trouble with C syntax...and well some of my code may well be wrong but I think I have given it a good attempt. It is meant to display 'EP2'. If anyone could help me just get the code working I would be very grateful. If anyone spots any glaring errors could someone please give me help with this. I am new to C and this course has thrown me in the deep end when it comes to programming.
#include <hidef.h> /* for EnableInterrupts macro */
#include "derivative.h" /* include peripheral declarations */
#define E_Display 0x79 //Digital display for 'E'
#define P_Display 0x73 //Digital display for 'P'
#define Two_Display 0x57 //Digital display for '2'
#define DP_Off 0x80 //Used to turn Decimal Point off
#define All_Off 0x00 //Used to turn all bits off
#define All_On 0xFF //Used toturn all bits on
#define Drive_Segment_Bus 0x3F //Used to drive the output
#define Mask_Digits 0x03 //Masking bits 7-2 off '00000011'
void main (void) {
// SET DDRs for output ports
for (;
![Smiley Wink :smileywink:](http://freescale.i.lithium.com/i/smilies/16x16_smiley-wink.gif)
//Repeat forever
{
Output_Seven_Segments(E_Display,1) ;
delay(1); //Call a delay subroutine
Output_Seven_Segments(P_Display,2) ;
delay(1);
Output_Seven_Segments(Two_Display,3) ;
delay(1);
}
}
void delay(long int n)
{
long int i;
unsigned int j;
for (i=0; i<n; i++)
for (j=0; j<100; j++)
{}
}
void Output_Seven_Segments (unsigned char segments, unsigned char digit)//this doesnt work!
{
segments == 0;
digit == 0;
//Remember: segments variable is formed as:
// DP g f e d c b a
if (digit==Two_Display) //This is the broken display
segments=FixDigit2(segments); //Call a subroutine to mangle all bits
PTFD == All_Off; // TURN ALL DIGITS OFF
PTBD == Drive_Segment_Bus;//DRIVE SEGMENTS BUS with segments<6:0>
PTFD == Mask_Digits;//Mask digit bits <7:2> off, so we only end with bits <1:0>
//(i.e. there are only 4 displays)
switch (PTFD) {
case 0:
Mask_Digits == 1;//Drive Most significant digit ON
PTFD == Mask_Digits;
break;
case 1:
Mask_Digits == 2;//Drive Next digit ON
PTFD == Mask_Digits;
break;
case 2:
Mask_Digits == 3;//Drive Least significan digit ON
PTFD == Mask_Digits;
break;
case 3:
PTAD == 0xFF; //Drive LED bar graph ON
break;
}
}
//Note: if your display is broken also include the following subroutine which is called to remangle the broken bits. Otherwise just look at how the routine shuffles bit around!
unsigned char FixDigit2(unsigned char value) {
unsigned char newval;
newval=0;
newval=newval|(value&0x01)<<6; //Bit 0 becomes 6
newval=newval|(value&0x02)>>1; //Bit 1 becomes 0
newval=newval|(value&0x04)<<5; //Bit 2 becomes 7
newval=newval|(value&0x40)>>4; //Bit 6 becomes 2
newval=newval|(value&0x80)>>6; //Bit 7 becomes 1
newval=newval|(value&0x38); //And bits 543 are copied undisturbed
return (newval);
}
for(;
![Smiley Wink :smileywink:](http://freescale.i.lithium.com/i/smilies/16x16_smiley-wink.gif)
{
__RESET_WATCHDOG(); /* feeds the dog */
} /* loop forever */
/* please make sure that you never leave main */
}
}
Message Edited by karmabobby on 2008-03-28 02:25 PMMessage Edited by karmabobby on 2008-03-28 02:26 PMMessage Edited by karmabobby on 2008-03-28 02:26 PMMessage Edited by karmabobby on 2008-03-28 02:30 PMMessage Edited by karmabobby on 2008-03-28 02:31 PMMessage Edited by karmabobby on 2008-03-28 02:32 PMMessage Edited by karmabobby on 2008-03-28 02:33 PM