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guest
Guest
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| variable delay |
 Posted: Fri Jan 13, 2006 6:00 am |
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Hi every body
I would like to aske about how I can control the value of the delay when I tried to put any variable inside the bracktes the programme give strange result
I triad to use fixed value of delay and make variable loop but also not work also I traid the follwoing function which suggested by PCM programmer but also not work when I put any variable for the value variable it give srange result any help pleas
| Code: |
#include <16F877.H>
#fuses HS,NOWDT,NOPROTECT, PUT, BROWNOUT, NOLVP
#use delay(clock=8000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
//----------------------------------
void long_delay_us(long count)
{
char i;
i = (char)(count >> 8);
while(i >= 1)
{
i--;
delay_us(253);
restart_wdt();
}
delay_us((char)count);
}
//---------------------------
main ()
{
long value;
long k;
value = 50000;
printf("Press Enter to start\n\r");
getc();
// Do a 10 second delay ( 200 * 50 ms = 10 seconds)
for(k = 0; k < 200; k++)
long_delay_us(value);
printf("Done\n\r");
while(1);
}
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ckielstra
Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands
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| Posted: Fri Jan 13, 2006 6:58 am |
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I compiled your program for my PIC18F458 and it worked fine.
Please describe in more details the 'strange result' you see.
Also add a link to the other thread you are referring to, or better, sign in to this forum so we can search on your author name.
Which compiler version are you using? |
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Guest
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| Posted: Fri Jan 13, 2006 8:05 am |
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when I want to generate square wave using this programe with certain period, simply when I put for example
[/code]int k=10;
value=50000+k | Code: |
the squre wave will generat with strange result but if I value=50000 every thing become fine
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Guest
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| Posted: Fri Jan 13, 2006 8:10 am |
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| my user name is PIC |
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ckielstra
Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands
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| Posted: Fri Jan 13, 2006 8:43 am |
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| Anonymous wrote: | | my user name is PIC |
No, it is Guest.
No wonder I couldn't find the error, you gave us a working program! 
I tried your program again with your suggested changes, but it still works perfectly. Please post a complete program showing the strange results you see.
You still haven't described what the strange results are and please, again, mention your compiler version! |
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PIC
Joined: 13 Jan 2006
Posts: 3
Location: Malaysia
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| Posted: Fri Jan 13, 2006 8:49 am |
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I will give u full description of my compiler:CCS PCM C compiler version 3.181
as I said when I put value=A+50000 they give wrong result which mean I use variable A for the value when I use value =50000 it work.
wrong result mean they will not give u the delay as u adjust by changing the value of A
fine  |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Jan 13, 2006 5:25 pm |
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You need to post a program which uses the variable 'A', and
also shows the declaration of 'A'.
Don't tell us about it in words. Post a short program that shows
the problem. |
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PIC
Joined: 13 Jan 2006
Posts: 3
Location: Malaysia
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| Posted: Fri Jan 13, 2006 8:28 pm |
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this is sample from my program
| Code: | #include <16F877A.H>
#fuses HS,NOWDT,NOPROTECT, PUT, BROWNOUT, NOLVP
#USE DELAY( CLOCK=20000000 )
#use rs232(baud=115200, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
#USE FAST_IO(A)
#USE FAST_IO(B)
#byte port_a=5
#byte port_b=6
static byte CONST UP_MAP0[8] = { 0x01,0x03,0x07,0x0f,0x1f,0x3f,0x7f,0xff };
static byte CONST UP_MAP1[8] = { 0xfe,0xfc,0xf8,0xf0,0xe0,0xc0,0x80,0x00 };
//----------------------------------
void long_delay_us(long count)
{
char i;
i = (char)(count >> 8);
while(i >= 1)
{
i--;
delay_us(253);
restart_wdt();
}
delay_us((char)count);
}
void main(){
char k=10;
long value1,value2,value3,value4,value5;
char cnt=0;char tnt=0;
SETUP_ADC_PORTS(NO_ANALOGS);
set_tris_a(0xfc);
set_tris_b(0x00);
port_a = 0x00,
port_b = 0x00,
value1=(6588*k)/180;
value2=(20628*k)/180;
value3=(17982*k)/180;
value4=(17118*k)/180;
value5=(55368*k)/180;
for(;;) { if (tnt==40) tnt=0; if(tnt%2==1)
port_a =0x01;else port_a=0x02;
long_delay_us(value1);
while(cnt<=3) {
switch (cnt) {
case 0:
port_b = UP_MAP0[0];
long_delay_us(value2) ;
break;
case 1:
port_b = UP_MAP0[1];
long_delay_us(value3);
break;
case 2:
port_b = UP_MAP0[2];
long_delay_us(value4);
break;
case 3:
port_b = UP_MAP0[3];
long_delay_us(value5);
break; }cnt++;}} |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Jan 13, 2006 10:03 pm |
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The problem is that you need to tell the compiler to use a data type
that is large enough to hold the intermediate result of your equations.
In CCS, a "long" data type is a 16-bit unsigned value. The largest
value it can hold is 65535. If you look at your equations, all of
the results of the multiplication are larger than 65535. So, the
results will be truncated.
Run the following program. Notice what the output values are.
Then change the declaration of "k" to be an "int32". Re-compile
and run the program again. See the improvement.
| Code: | #include <16F877.H>
#fuses XT, NOWDT, NOPROTECT, BROWNOUT, PUT, NOLVP
#use delay(clock=4000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
//===============================
void main()
{
char k=10;
long value1,value2,value3,value4,value5;
value1=(6588*k)/180;
printf("value1 = %LU\n\r", value1);
value2=(20628*k)/180;
printf("value2 = %LU\n\r", value2);
value3=(17982*k)/180;
printf("value3 = %LU\n\r", value3);
value4=(17118*k)/180;
printf("value4 = %LU\n\r", value4);
value5=(55368*k)/180;
printf("value5 = %LU\n\r", value5);
while(1);
} |
----------
Edited to change 65536 to the actual max value of 65535.
Last edited by PCM programmer on Fri Jan 13, 2006 11:15 pm; edited 1 time in total |
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PIC
Joined: 13 Jan 2006
Posts: 3
Location: Malaysia
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| Posted: Fri Jan 13, 2006 10:51 pm |
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thank you so much ,I grateful for your help ,it work fine thank you so much again
regards |
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