interrupt problem pic18f4620

I have problem when debug this code using mikroC.........


unsigned char sin_table[158]={0,3,6,9,12,15,18,21,24,27,30,
33,36,39,42,45,48,51,54,57,60,63,66,69,72,75,78,81,84,87,90,
96,99,102,105,107,110,113,116,119,122,125,127,130,133,136,138,
141,144,147,149,152,155,157,160,163,165,168,170,173,175,178,180,
183,185,188,190,193,195,197,200,202,204,207,209,211,214,216,218,
220,222,227,229,231,233,235,237,239,241,243,245,246,248,250,252,
254,255,257,259,261,262,264,266,267,269,270,272,273,275,276,277,
279,280,282,283,284,285,287,288,289,290,291,292,293,294,295,296,
297,298,299,300,301,302,303,304,304,305,306,306,307,307,308,308,
309,309,309,310,310,310,311,311,311,311,311,311,311,311,312};

unsigned int TBL_POINTER_NEW, TBL_POINTER_OLD, TBL_POINTER_SHIFT, SET_FREQ;
unsigned int TBL_temp;
unsigned char DUTY_CYCLE;

void interrupt(){

TBL_POINTER_NEW = TBL_POINTER_OLD + SET_FREQ;
if (TBL_POINTER_NEW == 312){
CCP1CON.P1M1 = ~CCP1CON.P1M1; //Reverse direction of full-bridge
}

DUTY_CYCLE = TBL_POINTER_NEW;
TBL_POINTER_NEW >>8;
CCPR1L = sin_table[DUTY_CYCLE];
TBL_POINTER_OLD = TBL_POINTER_NEW;
PIR1 = 0;

}

void main() {
SET_FREQ = 1;
TBL_POINTER_SHIFT = 0;
TBL_POINTER_NEW = 0;
TBL_POINTER_OLD = 0;
DUTY_CYCLE = 0;
PR2 = 312;
TRISC = 0x3F;
CCP1CON = 0x4C;
PIR1 = 0;
T2CON = 4; //TMR2 on, prescaler and postscaler 1:1
while (PIR1 == 0);
PIR1 = 0;
TRISC = 0;
PIE1 = 0x02;
INTCON =0xC0;

while(1);
}


when it goes to the interrupt function, suppose TBL_POINTER_NEW = 1(0+1=1) but it show 256. Is it something wrong with this code. Thank you...

TBL_POINTER_NEW >>8; : this code did nothing

I think he meant TBL_POINTER_NEW =>> 8; and not TBL_POINTER_NEW >> 8;

actually i try to shifting TBL_POINTER_NEW into 8 bit( since i got 256=1 0000 0000). So, it should get 1 right. But even, i change into TBL_POINTER_NEW>>=8 or i delete TBL_POINTER_NEW>>8 line, it still show 256 as answer. But when i try to implement this code with pic16f684(but with small sine table), it show the right answer.

Change DUTY_CYCLE to unsigned int variable and see if it works. Values greater than 255 can't be assigned to CCPR1L because it is a 8 bit register.

still got the same answer(256)

Post your project files in a zip file. What compiler do you use? Have you selected the right device for your project?

Explain what this part of code does?

i'm using MikroC PRO from Mikroelektronika, pic18f4620, frequency = 20MHz...

Remove this line.


Another thing I see in your code is that in the sine table, you have quite a lot of values larger than 255, whereas you declared sin_table as an 8-bit variable:

Hope this helps.
Tahmid.

Another thing I see in your code is that in the sine table, you have quite a lot of values larger than 255, whereas you declared sin_table as an 8-bit variable:

Click to expand...

I missed finding his error(s).

Tahmid said:

Remove this line.

Code:

TBL_POINTER_NEW >>8;

Another thing I see in your code is that in the sine table, you have quite a lot of values larger than 255, whereas you declared sin_table as an 8-bit variable:

Code:

unsigned [B]char [/B]sin_table[158]

Hope this helps.
Tahmid.

Click to expand...

thank you, i think i already got the answer