#include <htc.h>
#define _XTAL_FREQ 20000000UL
typedef unsigned char UINT8;
typedef signed char INT8;
typedef unsigned int UINT16;
typedef signed int INT16;
//Connection of Seven segment display
#define SEVEN_SEGMENT_LAT PORTD
#define SEVEN_SEGMENT_TRIS TRISD
//MUX Control
#define MUX_PORT PORTB
#define MUX_START_POS 1 //From which bit on port the select lines start
//MUX settings
#define MUX_DISP_COUNT 4 //Number of displays
//Global Varriable
UINT8 DisplayArray[MUX_DISP_COUNT];//Holds 'data' for each disp
void SevenSegmentWrite(UINT16 n)
{
/*
n=data to dislay
example:
n=1234 will display 1234 in a 4 segment display
Working:
This function breaks apart a given integer into separete digits
and writes them to the display array i.e. digits[]
*/
UINT8 i=0;
UINT8 j;
while(n)
{
DisplayArray[i]=n%10;
i++;
if(i==MUX_DISP_COUNT)
break; //We don't have room for more digits
n=n/10;
}
//Fill Unused area with 0
for(j=i;j<MUX_DISP_COUNT;j++) DisplayArray[j]=0;
}
void WriteSegment(UINT8 num)
{
switch (num)
{
case 0:
//-GFEDCBA
SEVEN_SEGMENT_LAT = 0B01000000;
break;
case 1:
//-GFEDCBA
SEVEN_SEGMENT_LAT = 0B01111001;
break;
case 2:
//-GFEDCBA
SEVEN_SEGMENT_LAT = 0B00100100;
break;
case 3:
//-GFEDCBA
SEVEN_SEGMENT_LAT = 0B00110000;
break;
case 4:
//-GFEDCBA
SEVEN_SEGMENT_LAT = 0B00011001;
break;
case 5:
//-GFEDCBA
SEVEN_SEGMENT_LAT = 0B00010010;
break;
case 6:
//-GFEDCBA
SEVEN_SEGMENT_LAT = 0B00000010;
break;
case 7:
//-GFEDCBA
SEVEN_SEGMENT_LAT = 0B01111000;
break;
case 8:
//-GFEDCBA
SEVEN_SEGMENT_LAT = 0B00000000;
break;
case 9:
//-GFEDCBA
SEVEN_SEGMENT_LAT = 0B00010000;
break;
}
}
void Wait()
{
UINT8 i;
for(i=0;i<1;i++)
__delay_ms(10);
}
void main()
{
//Set Up I/O Ports
TRISB0=0;
SEVEN_SEGMENT_TRIS = 0B10000000;//Disp is connect from 0-6 last bit 7 is unused
//MUX select lines
TRISB = 0B11100001;
//Init TIMER0
T0CS=0; //Timer Clock source is intruction clock that is 5MHz
PSA=0; //Prescaler is assigned to TIMER0
PS2=1;
PS1=1;
PS0=0; //Prescaler = FCPU/128
TMR0IE=1; //Enable Timer0 Interrupt
PEIE=1; //Enable Peripheral Interrup
//Enable Interrupts Globally
ei();
while(1)
{
for (UINT16 i=0;i<10000;i++)
{
SevenSegmentWrite(i);
Wait();
}
}
}
//Our Interrupt Service Routine
void interrupt ISR()
{
if(TMR0IE && TMR0IF)
{
//TIMER0 Overflow Interrupt
//First Clear the INT flag
TMR0IF=0;
// Current display selected
//Value of "static varriable" is retained between calls
static int i;
//Switch On Display Pointed by 'i'
MUX_PORT = (~(1<<(i+MUX_START_POS)));
//Latch digit on it
WriteSegment(DisplayArray[i]);
//On each time out select next display
i++;
//If on last display then goto first
if(i==MUX_DISP_COUNT)
i=0;
}
}
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Avinash
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I have just written some very similar code but for a Atmel sam7 device (AT91SAM7S256) to control the same display. The code can be found at http://github.com/steakunderscore/AVRJukebox in the display.h and display.c files.
i am interested on the seven-segment display. But more specifically on 7-segment display body bathroom scale that is non LCD. Because i am working on a project that requires me to display the output from a weighing machine to the computer. Unfortunately i do not know how to disassemble and find the output port(s) of the current digital LCD bathroom scales found in the market. Is there any way I can execute my project? thanks.
can i get a detailed description of port connections with 7seg. thanks.
please present schematic for your code