pc based digital clock via parallel port using c language

[loloysh]

How are you every one?

I have this project and I already have a code and the circuit, but I studied assembly language it's supposed to display the hours and minutes.

Does any one know assembly and c language?

Here's the code:

TITLE CLOCK.ASM
    DOSSEG
    .MODEL SMALL
    .STACK 0100H
    .DATA
    PRINTERPORTBASEADDRESS equ 378h
 
    .CODE
    MAIN PROC
    MOV AX, @DATA
    MOV DS, AX
 
    CALL RTIME ; READ TIME
    CALL DisplayTime ;DISPLAY TIME
 
    MOV AX, 4C00H
    INT 21H
    MAIN ENDP
 
    RTIME PROC
    MOV AH, 02H
    INT 1AH
    RET
 
    ; CH - HOUR
    ; CL - MINUTES
    ; DH - SECONDS
    RTIME ENDP
 
    DisplayTime PROC
    push DX ; was DH
    push CX ; was CL
    ;
    mov AL,CH
    mov DX,PRINTERPORTBASEADDRESS
    out DX,AL
    mov AL,01h
    mov DX,PRINTERPORTBASEADDRESS+2
    out DX,AL ; enable display
    call Delay
    ;
    mov AL,00h
    mov DX,PRINTERPORTBASEADDRESS+2
    out DX,AL
    pop AX ; pop CL (minutes)
    mov DX,PRINTERPORTBASEADDRESS
    out DX,AL
    mov AL,02h
    mov DX,PRINTERPORTBASEADDRESS+2
    out DX,AL ; enable display
    call Delay
    ;
    mov AL,00h
    mov DX,PRINTERPORTBASEADDRESS+2
    out DX,AL
    pop AX ; pop DH (seconds)
    mov AL,AH
    mov DX,PRINTERPORTBASEADDRESS
    out DX,AL
    mov AL,08h
    mov DX,PRINTERPORTBASEADDRESS+2
    out DX,AL ; enable display
    call Delay
    ;
    mov DX,PRINTERPORTBASEADDRESS+2
    mov AL,00h
    out DX,AL
    ret
 
    DisplayTime ENDP
 
    Delay Proc
    MOV CX, 00100h
    X: PUSH CX
    MOV CX, 0FFFFh
    Y: LOOP Y
    POP CX
    LOOP X
    RET
 
    Delay ENDP
    END

Thank you for your time.

This is the circuit diagram

http://www.electvillage.com/upload//...adbd174136.png

[donbock]

Is there a problem with this assembly language program?

[loloysh]

But there's small problem with minutes don't work probably
Thank you for time and writing comment

[loloysh]

 
#define A 0
#define B 1
#define C 2
#define D 3
#define E 4
#define F 5
#define G 6
 
typedef struct {int seg[7];} digit_t;
 
digit_t disp[4];
/*
 *  AAAA
 * F    B
 * F       B
 *  GGGG
 * E    C
 * E       C
 *  DDDD
 */
 
digit_t int2segs[10] = {
/* A  B  C   D  E  F   G */  
  {1, 1, 1,  1, 1, 1,  0},  /* 0 */
  {0, 1, 1,  0, 0, 0,  0},  /* 1 */
  {1, 1, 0,  1, 1, 0,  1},  /* 2 */
  {1, 1, 1,  1, 0, 0,  1},  /* 3 */
  {0, 1, 1,  0, 0, 1,  1},  /* 4 */
  {1, 0, 1,  1, 0, 1,  1},  /* 5 */
  {1, 0, 1,  1, 1, 1,  1},  /* 6 */
  {1, 1, 1,  0, 0, 0,  0},  /* 7 */
  {1, 1, 1,  1, 1, 1,  1},  /* 8 */
  {1, 1, 1,  1, 0, 1,  1}   /* 9 */
};
 
void print_dig (digit_t d, char *name)
{
    int i;
 
    printf("%s\n", name);
    for (i=0; i < 7; i++) {
    printf("   Segment %c : %6d\n", 'A'+ i, d.seg[i]);
    }
}
 
void display_dig (digit_t *d, int n)
{
    digit_t symbol;
    int i;
 
    if (n > 9) {
    printf("\n error digit too large \n");
        exit(1);
    }
    symbol = int2segs[n];
 
    for (i=0; i < 7; i++) {
    d->seg[i] += symbol.seg[i];    /* Add value for this tick */
    }
}
 
void display(int h, int m, int s)
{
    int m1, m10, h1, h10;
 
    m1 = m%10;                /* get individual digits */
    m10 = m/10;
    h1 = h%10;
    h10 = h/10;
 
    if (h10 > 0)            /* leading zero supression */
    display_dig(&disp[0], h10);
    display_dig(&disp[1], h1);
    display_dig(&disp[2], m10);
    display_dig(&disp[3], m1);
}
 
main()
{
    int hour, min;
 
    for (hour = 1; hour <= 12; hour++) {
    for (min = 0; min < 60; min++) {
        display(hour, min, 0);
    }
    }
    print_dig(disp[0], "Hours Tens");
    print_dig(disp[1], "Hours Ones");
    print_dig(disp[2], "Minutes Tens");
    print_dig(disp[3], "Minutes Ones");
}

Is there any problem if I use it for my project ??

[zmbd]

loloysh
Just what is it that you're asking?
Are you having errors with this?

[donbock]

I assume the assembly language in your initial post is for an x86-style microprocessor. The x86 architecture allows for both memory-mapped I/O and port I/O. The OUT command used in lines 36,39,44,47,50,55,59,62,67 of the assembly-language program performs port output. Unfortunately for you, port I/O is incompatible with Standard C -- no combination of C instructions will induce the compiler to emit an OUT command. You either need a nonstandard compiler extension or your C program needs a way to invoke explicit assembly language instructions. There are two ways for C code to invoke explicit assembly language instructions: inline via the asm keyword or through a C-callable assembly language subroutine.

These are advanced topics. It would help me to know your familiarity with x86 assembly and C before I go into more detail.

@loloysh: did you write these two programs or are you trying to understand code that somebody else wrote?

[donbock]

It isn't such an advanced topic if your compiler provides a nonstandard library function that does the hard part for you. The following functions are part of the MSDN run-time library (assuming your program executes in a Microsoft environment).

#include <conio.h>
int _outp(
   unsigned short port,
   int databyte 
);
unsigned short _outpw(
   unsigned short port,
   unsigned short dataword 
);
unsigned long _outpd(
   unsigned short port,
   unsigned long dataword 
);

The original assembly language program does a few more tricky things that you need to handle properly in C:

• Line 17: INT 21H
• Line 22: INT 1AH
• Lines 72-81: Delay Proc

[donbock]

The link to the circuit diagram wants to install a driver before it will show me the diagram ... I'm not willing to do that. Please describe the important parts of the circuit:

1. Does each data bit drive a segment of the display or does your circuit include a binary/BCD-to-segment converter?
2. If each data bit drives a segment, then are the data bits active high or active low?
3. For each digit of the display, what control signal strobes that digit; and is the strobe active high or active low?
4. What is the minimum width of the strobe pulses?