Closing / stopping a switch statement

I am currently writing a piece of code for a PIC18F1229 microcontroller using the software MXLAB v3.45 .
I have been tasked with flashing the middle segment at a speed of 1 flash per second and to stop it after 4 seconds using a switch stamement. I have managed to get the middle segment to flash at one flash per second but I am unsure how to close the switch statement. Would this be with a else statement and if so else what? Else false as all my other values are "true" . I have trialled using the "end" statement which flags an error as undefined indentifier. would this be a local indentifier or global. Please see my code below and perhaps make you might see where I have made a simple mistae.

This is my timer loop :
insert

Code:

---


WriteTimer0(0);
 INTCONbits.TMR0IF=0;
 while(TRUE) //Loop forever
 {
        Display(ucCount);
  ucCount++;
  if(ucCount>7) ucCount=0;
  while (INTCONbits.TMR0IF==0);
  INTCONbits.TMR0IF=0;
        WriteTimer0(46004); 
        //1/10Mhz x 4 x 64 = 25.6 us. 500000/25.6 = 19531. 65545 - 19531 = 46004
       
    }
       
    CloseTimer0();

---

this is my switch statement:
insert

Code:

---

{
 switch (ucHexDigit)     
 {
  case 0:
  LATB=0b00101011;
  LATA=0b11111111;
  break;
           
        case 1:
  LATB=0b11111111;
  LATA=0b11111111;
  break;
           
        case 2:
  LATB=0b00101011;
  LATA=0b11111111;
  break;
           
        case 3:
  LATB=0b11111111;
  LATA=0b11111111;
  break;
           
        case 4:
  LATB=0b00101011;
  LATA=0b11111111;
  break;
           
        case 5:
  LATB=0b11111111;
  LATA=0b11111111;
  break;
           
        case 6:
  LATB=0b00101011;
  LATA=0b11111111;
  break;
           
        case 7:
  LATB=0b11111111;
  LATA=0b11111111;
  break;
                         
  default: //display turned off
  LATB=0b11111111;
  LATA=0b11111111;
            break;   
                   
 }
}

---

As can be seen above The last statement deault turns all LEDS off and after this I would like to stop the switch statement from looping around again.

Any advice would be appreciated.

Instead of writing while(TRUE), write while(display_turned_on), which is set to 1 before the loop, and then in the default case of the switch set display_turned_on to 0.

This is not a very good switch. Firstly, LATA is set to the same thing in every branch. Secondly, LATB is assigned just two different values based on whether or not it's even. Also, binary constants are not standard. We would usually use hex.

Code:

---

ucHexDigit = get_it();  // "get_it" represents whatever needs to be done to set ucHexDigit
while (ucHexDigit < 8) {  // I'm assuming "uc" means unsigned char so it can't be < 0
    LATB = ucHexDigit % 2 == 0 ? 0x2B : 0xFF;
    LATA = 0xFF;
    ucHexDigit = get_it();
}

---

Or if your method of setting ucHexDigit allows it:

Code:

---

while ((ucHexDigit = get_it()) < 8) {
    LATB = ucHexDigit % 2 == 0 ? 0x2B : 0xFF;
    LATA = 0xFF;
}

---

You can create a label and use goto to jump to it. Some consider this bad style, but sometimes it is very useful.

Code:

---

while(1)
{
    ...
    {
        switch (ucHexDigit)
        {
        case 0:
            ...
            break;
        case 1:
            ...
            break;
        ...
        default:
            LATB = 0xff;
            LATA = 0xff;
            goto done;
        }
    }
}

done:
/* Rest of code. */

---

HI Laserlight

I modified the code as suggested but I still have my LED continuously flashing :(

while(DisplayTurnedOn) //Loop forever
{
Display(ucCount);

case 7:
LATB=0b11111111;
LATA=0b11111111;
break;

default: //display turned off
//LATB=0b11111111;
//LATA=0b11111111;
DisplayTurnedOff ;
break;

Quote:

---

Originally Posted by c99tutorial

You can create a label and use goto to jump to it. Some consider this bad style, but sometimes it is very useful.

Code:

---

while(1)
{
    ...
    {
        switch (ucHexDigit)
        {
        case 0:
            ...
            break;
        case 1:
            ...
            break;
        ...
        default:
            LATB = 0xff;
            LATA = 0xff;
            goto done;
        }
    }
}

done:
/* Rest of code. */

---

---

Hi C99 I have tried doing the above but when you have declared "done" have you done this as a global or local void? as while 1 in my case is true but if i create a done void should this allow my LED to only flash 4 times?

Quote:

---

Originally Posted by lyndonrobertson

Hi C99 I have tried doing the above but when you have declared "done" have you done this as a global or local void?

---

The label should be local to a function. It does not have a type, it is just a label. e.g.

Code:

---


int my_function()
{
  ...
  goto some_label;
  ...

some_label:
  ...
}

---

Using labels means you understand the logic already and are taking full control of the code. If you don't know how many times your body will be executed, don't use goto.