Hello mister_ezeh,
First of all, I really really hope your code doesn't look like that on your compiler
Seriously, the first step to a working code, is it's readability. Now let's move on.
You haven't said what MCU you have used, so judging by the registers and stuff, I came to a conclusion that it was PIC16F877.
If I am wrong, then only a few registers need to be corrected, according to the datasheet of the MCU you have.
Now - the code:
1 - First thing I saw is that interrupt routine. I'd clear the TMR0IF flag as the first instruction, after the check, just in case. If no prescaler is used, you might end up with yet another interrupt, while you are still in the first one, increasing the
cnt variable, having in mind that the MCU clock is pretty fast.
2 - Writing values to the TMR0 register is unnecessary, as it may lead to unpredicted events. Writing this register blocks the timer for 2 cycles, also sets and resets a bunch of other stuff (you can find the details about it in the datasheet), also dangerous while in the interrupt - so just leave it be, as it cycles from 0 to FF, increasing it's value with each clock pulse (or divided by the prescaler), if you set it to be a 'timer' and not 'counter' (with the T0CS bit of the OPTION_REG register)
Code: Select all
void interrupt()
{
if (TMR0IF_bit)
{
TMR0IF_bit = 0; // clear TMR0IF
cnt++; // increment counter
}
}
Ok, let's move on.
You can do all the initialization inside the main(), but a good practice is to break the code into functions, so I did that - a habit I have - it's not mandatory for the code to work, but it adds to the readability. I named my init function
InitMain(). Read the comments for the explanation:
Code: Select all
void initMain()
{
OPTION_REG = 0b10000100; // Assign prescaler 1:32 to TMR0 and disable pullups (or 0x84)
TRISB = 0x00; // PORTB is output
PORTB = 0x00; // Initialize PORTB
TMR0 = 0x00; // Timer0 initial value (again - it's not needed, but let us start it clean - from 0)
INTCON = 0xA0; // Enable TMRO interrupt & global interrupt
cnt = 120; // Initialize cnt (I've set it so as soon as I call the function, the screen will display the timer txt, avoiding blank screen for the first 'timer-- ;' cycle)
ADCON0 = 0b00000000; // Analog channel select @ AN0 (I have connected my board this way, again it might differ from your MCU and connections)
ADCON1 = 0x00;
TRISA = 0b00000001; // PORTA All Outputs, Except RA0
Lcd_Init(); // Initialize LCD
ADC_Init(); // Initialize ADC module (not necessary if you use ADC_Read(ch))
Lcd_Cmd(_LCD_CLEAR); // Clear display
Lcd_Cmd(_LCD_CURSOR_OFF); // Cursor off
}
Ok now we have a nice function for the initialization of everything we use. Next part:
Code: Select all
void int_delay()
{
do
{
if (cnt >= 120) // I am checking for >= 120 because the value might get increased beyond this, if I wait for too long. Timer increases it, right ?
{
PORTB.F2 = ~PORTB.F2; // Toggle PORTB LEDs
timer--;
cnt = 0; // Reset cnt
inttostr( timer, text);
Lcd_Out(1,1,"conctn to source");
Lcd_Out(2,6,text);
Lcd_Out(2,7,"sec");
if(timer==0)
{
INTCON.T0IE=0;
Lcd_Cmd(_LCD_CLEAR);
Lcd_Out(1,1,message1);
}
}
}
while (timer); //do - while loop. I suppose you wanted to countdown till the timer = 0, right ? If so, you need to stay in the loop until it happens...
}
As you can see, it's slightly modified, also I have used a do-while loop to wait for the
voltage connection to happen, this was what you originally wanted, right ? Moving on.
After this loop, I am in the endless loop which will sample the voltage and display a warning if
dangerous voltage appears. Also I've made it so the LED turns off, once you're under the
dangerous voltage level.
Code: Select all
void voltagecon()
{
while (1)
{
voltage = ADC_Read(0);
val=(voltage*5)/1023;
voltage1 = (voltage * 5 * 65)/ (1023);
IntToStr(voltage1, volt); // it converts integer value into string
Ltrim(volt); // Ltrim changes the string's length, by stripping the blank places out.
Lcd_Out(2,1,"Voltage = ");
Lcd_Out(2,11, volt); // ...thus 'volt' is not formatted properly, but it's good enough for this example.
Lcd_Out(2,16,"V");
if(voltage1 > 260)
{
RB2_bit = 1;
Lcd_Out(2,1,"DANGER ");
Delay_ms(1000);
} else { //my personal touch of awesomeness ! JK :D Making sure the led goes off after the value has dropped under the threshold,
RB2_bit = 0; //maybe you even don't want that, but there it is...
}
}
}
As you can see, not much is changed here. I've used ' while (1) {...some looping code} ', instead of ' do {...some looping code} while (1) ' - the same thing, only a bit shorter...
Lastly - the main() function:
Code: Select all
void main()
{
initMain();
int_delay(); //this function will run till the 'timer' variable gets to 0. after that, we break out of the loop and move on to the next function
voltagecon(); //this function samples the voltage, displays stuff and it's an endless loop. Once in, program never leaves it.
}
A short piece of code, just calling in the functions.
I will send you the finished project, so you can try it yourself. It's for the PIC16F877, if you have different one, just adjust the project accordingly.
Hope this helps, best regards.
