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hadeelqasaimeh
Joined: 05 Jan 2006
Posts: 105
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| problem with gethex function |
 Posted: Mon Aug 06, 2007 5:33 pm |
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hi
i want to get array of hex from rs232 using gethex function.i get them correctly, now i need to deal with each one of the array independent of other
i cant get hex in location 4(for example)>>>so what to do?
i hope you can understand me
here is my TX code:
| Code: |
#include <16f877a.h>
#fuses xt,NOWDT,NOLVP
#use delay(clock=4000000) //one instruction=1us
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7,ERRORS)
int8 value;
void main() {
again:
delay_ms(5000);
printf("01\r\n");
delay_ms(100);
printf("02\r\n");
delay_ms(100);
printf("3\r\n");
delay_ms(100);
printf("4\r\n");
delay_ms(100);
printf("*\r\n");
delay_ms(100);
printf("01\r\n");
delay_ms(100);
printf("&\r\n");
printf("01\r\n");
delay_ms(100);
printf("02\r\n");
delay_ms(100);
printf("45\r\n");
delay_ms(100);
printf("02\r\n");
goto again;
}//MAIN
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and RX code:
| Code: |
#include <16f877a.h>
#include <stdlib.h>
#fuses xt,NOWDT,NOLVP
#use delay(clock=4000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)
#include <INPUT.C>
int RX[10] ,value[10];
static int1 flag;
static int8 i,n,f,t,address;
#int_rda
void serial_isr() {
RX[i++]=gethex();
flag=1;
}
void main()
{
enable_interrupts(GLOBAL);
enable_interrupts(INT_RDA);
flag=0;
i=0;
while(1) {
printf("%x\r\n",RX[i]);
delay_ms(500);
i++;
if (flag==1)
{
// for(i=0;i<11;i++)
// {
// value[i]= RX[i];
// write_eeprom(address,value);
// f++;
// i++;
// }//for
flag=0;
}//if
/////////empty///////
for(i=0;i<11;i++)
{
RX[i]=0;
}//for
}//while
}//main
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as it clear in rx code, in need to save each hex value in a location in eeprom
another point, when i send "*" i didn't receive it as hex!!!!
regards,
hadeel |
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Ttelmah
Guest
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| Posted: Tue Aug 07, 2007 2:49 am |
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Of course you don't.
'Gethex', accepts two hex digits. It does not convert a value to hex for you. As such, it'll accept the characters 0 to 9, and A to F. As such, the first printf, sends the two digits '0' and '1', and this value (1), will be put into the first line of the array. However then things go wrong. 'Gethex', does not understand line feed and carriage return, so will try to treat these as hex digits, and because both are below '9' (in ASCII terms), it'll result in a garbage high value being put in the next line.
There are then loads of other potential problems. Using the same counter, inside the interrupt, and in the main code, will result in values being placed almost at random in the array. If the interrupt occurs inside the counting loop in main, i, could be at any value...
Then, the limit checking for the array is wrong. You allocate arrays of ten values, which are indexed as 0...9, yet allow i to count to 10...
Start by just sending one value. Modify gethex, or wite your own version, to see the carriage return as the end of the value. Add checking for values like '*' and '&' (what do you actually want to do with these?...). Once you have this working, then add the loop to send the multiple values (getting the counter right). Remembr that the write counter in the interrupt, should be separate from the output conter in main.
Best Wishes |
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hadeelqasaimeh
Joined: 05 Jan 2006
Posts: 105
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| Posted: Tue Aug 07, 2007 5:03 pm |
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thank you Ttelmah, i modify my code (such as ex_intee)and i can get 10 hex ,but when save them in eeprom i get somthing strange
for example i send(010203040506070809)
i gethex each one,and write in eeprom,to make sure i try to read from eeprom and the result was:
aa
01
aa
02
aa
03
aa
04
aa
05
.
.
.
.
09
aa
but why?!!!  |
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Ttelmah
Guest
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| Posted: Wed Aug 08, 2007 2:04 am |
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I'd suspect your counter.
Remember in your interrupt, you are counting _hex characters_, while in the EEPROM, you are counting _bytes_. The latter each hold two hex characters. Hence for the second 'gethex', if you are counting the incoming characters, the counter will be '2', while the address required in the eeprom, would be '1'. Hence you are writying the values to alternate locations in the eeprom, and leaving the ones between, containing whatever they had before...
Best Wishes |
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hadeelqasaimeh
Joined: 05 Jan 2006
Posts: 105
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| Posted: Wed Aug 08, 2007 5:38 pm |
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hi Ttelmah
yes,thats right
so i try to use
| Code: |
if((i%2)==0)
adress++;
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where i is hex counter
it works good up to 18 numbers then it get mixing agian
thank you Ttelmah very much |
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Ttelmah
Guest
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| Posted: Thu Aug 09, 2007 4:24 am |
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Since there are 18 characters in the string you show, and if this is from a terminal package, this will be followed by a CR, or CR/LF, then this is presumably why it then goes wrong at this point...
Best Wishes |
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hadeelqasaimeh
Joined: 05 Jan 2006
Posts: 105
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| Posted: Fri Aug 10, 2007 6:01 pm |
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hi Ttelmah
i make simulation on two pics
thank you, when i duplicate the counter its work fine,but there is question on my mind:
when i use ds1307(real time driver) may this affect rs232 intterupt (rda) work?i mean is any one of them disable the other???
thank you all |
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