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atomy_kwang
Joined: 28 Jun 2008
Posts: 24
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| I have a problem about receive data (string) in CCS C |
 Posted: Sun Sep 07, 2008 7:56 am |
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This is my code, it have something wrong.
| Code: |
#include <16f877a.h>
#fuses HS,NOLVP,NOPROTECT,NOWDT
#use delay(clock = 20000000)
#use rs232(baud=9600,xmit=pin_c6,rcv=pin_c7)
#byte port_b=6
#INT_RDA
void receive_data(void)
{
char data[20] ;
gets(data)
while(data == 'radio')
{ output_high(pin_b0);
delay_ms(1000);
output_low(pin_b0);
delay_ms(1000);
}
while(data == 'tv')
{ output_high(pin_b0);
delay_ms(1000);
output_low(pin_b0);
delay_ms(1000);
}
}
void main()
{
set_tris_b(0x00);
port_b=0x00;
enable_interrupts(GLOBAL);
enable_interrupts(INT_RDA);
while(true)
{
;
}
} |
I have a problem that i would like everyone to help.
1. I want to receive data in string but the loop while
it cannot do
2. Assume that i succeed in solution 1. If receive data correct, it is
work especially in that loop. Although I put the data 2 correct
it does not work.
I want to do on data that i sent from vb.
Assume i send the word 'radio' led at rb0 on, but if i send 'tv'
led at rb1 on and rb0 off.
help me please |
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meereck
Joined: 09 Nov 2006
Posts: 173
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| Posted: Sun Sep 07, 2008 10:20 am |
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2 thoughts:
1) for comparing string, use C function strcmp().
You have to have:
#include <string.h>
However, strings have to be terminated by '\0' character, not "\r".
2) dont use delay_ms in any interrupt routine.
You can use timers and their interrupts, or the main loop for delay purposes |
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Ttelmah
Guest
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| Posted: Sun Sep 07, 2008 11:55 am |
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Also, understand, that INT_RDA, implies just _one_ character is waiting to be received. 'gets', waits for a complete _string_ of characters, including a terminating line feed. Using gets, spoils the 'point' of using interrupts. If you want to wait for a whole string, do this in the main, and don't use interrupts. If you want to use interrupt driven serial, so you can do other things, look at ex_sisr, which shows how to buffer data from the interrupt. Do your own assembly into a 'string' in the main code.
Best Wishes |
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