Real time clock, increment and display on LED in C

Question

I have a loop for my clock, that I am trying to make an add 30 sec if keypad sends an x value of 30. It then displays on the LED display. It works, but I seem to be having an issue with adding 30 seconds and over 59 sec. The way it worked originally was it kept adding 30 to 60 to 90 + 120, etc. But I want it to roll over every 60 secs, when I add 30 sec. If I should rewrite the code, I am all game, but any leads would be helpful. Know this code is for an embedded item and is only a snippet. the inital set time is added before set loop, and is held as the value for test.

n=test;
for(i=0;i<n;i++){

        q = test %100;    /*q makes real time clock work in 60 sec decriments*/

         if(q==0){
            test = test - 40;
         }  
         key = KeypadReadPort();
         x = keys[key];
         if(x==30){           /*add 30 seconds during count*/
              n = n + 30;
              sec1=(test+30)%90;
              if(sec1>=60){
                min=q; 
                sec2=(test+30)%60;
                test=sec2+(100+q);
              } else if (sec1<60){
                test=test+30;
              }
           SevenSegWrite(test);/* display result on LED*/


         }
         test = test - 1;       /*count down tick*/
         SevenSegWrite(test);
         OSTimeDlyHMSM(0, 0, 1, 0);/*1 second tick*/
         if(test==0){

           for(i=0;i<750;i++){               /*buzzer*/
             PTT = PTT | 0x20;
             OSTimeDlyHMSM(0,0,0,1);
             PTT = PTT & 0xDF;
             OSTimeDlyHMSM(0,0,0,1);  
           }
         }
       }
      test=0;

Answer 1

I would do it this way. It works for me. You have a great start! You just need to break down your clock numbers a bit.

 if(start<15){
        min=0;                                                               /*microwave keypad numeric input method*/
       n = test;
       for(i=0;i<n;i++){
        q = test %100;               /*q makes real time clock work in 60 sec decriments*/

         if(q==0){
            test = test - 40;
         }  
         key = KeypadReadPort();
         x = keys[key];
         if(x==30){           /*add 30 seconds during count*/

              d4 = test % 10;
              d3 = (test / 10) % 10;
              d2 = (test / 100) % 10;
              d1 = (test / 1000) % 10;
              min=(d1*1000)+(d2*100);
              sec1=(d3*10)+d4;
              n = n + 30;
              sec2=(sec1+30)%90;

              if(sec2>=60){
                min=min+100; 
                sec1=(sec1+30)%60;
                test=sec1+(min);
              } else if (sec2<60){
                test=test+30;
              }
           SevenSegWrite(test);


         }
         test = test - 1;       /*count down tick*/
         SevenSegWrite(test);
         OSTimeDlyHMSM(0, 0, 1, 0);
         if(test==0){

           for(i=0;i<750;i++){               /*buzzer*/
             PTT = PTT | 0x20;
             OSTimeDlyHMSM(0,0,0,1);
             PTT = PTT & 0xDF;
             OSTimeDlyHMSM(0,0,0,1);  
           }
         }