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Dempsey
Joined: 24 Oct 2013
Posts: 13
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| Does printf inhibit gets? |
 Posted: Sat May 09, 2015 5:02 am |
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Hi,
I am trying to control one output through ESP8266. First I am initializing the ESP module, it works fine but if I send "be" string to the PIC (from android device through ESP), the output doesn't go to high state. I recognized if I delete the init(); statement and compile again the program and write to the PIC, the string handling works and the output go to high state.
But if I switch off the power supply I should play again this "game".
| Code: | #include<18f25k20.h>
#include<string.h>
#fuses nowdt,intrc_io,put,noprotect,nobrownout,
#use delay(clock=16Mhz)
#use rs232(baud=9600, xmit=PIN_C6,rcv=PIN_C7,bits=8,parity=N,stop=1)
char string[30];
void init (){
printf("AT+CWMODE=3\xD\xA");
delay_ms(1500);
printf("AT+CWJAP=\x22WIFI\x22,\x22PASS\x22\xD\xA");
delay_ms(5500);
printf("AT+CIPMUX=1\xD\xA");
delay_ms(1500);
printf("AT+CIPSERVER=1,1336\xD\xA");
}
void main (){
init();
while(true){
gets(string);
if ((string[10]=='b')&&(string[11]=='e')){
output_high(pin_b0);
}
if ((string[10]=='k')&&(string[11]=='i')){
output_low(pin_b0);
}
}
} |
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temtronic
Joined: 01 Jul 2010
Posts: 9242
Location: Greensville,Ontario
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| Posted: Sat May 09, 2015 5:26 am |
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Have a look at the CCS example ex_sisr.c. It's an ISR driven circular buffer. With any(all) serial communications you _need_ to have some form of buffering of the data coming into the PIC's UART. It only has a 2-3 char 'buffer' and will overrun aka 'stall', 'lockup', 'crash' when the 4th char arrives.
You also need to add 'errors' to the uses RS232(...options...) as that adds some code to prevent this 'overrun' error.
jay |
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asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
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| Posted: Sat May 09, 2015 10:26 am |
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also in the CCS library INPUT.C
look at
get_string()
which i successfully modified using an
addition of kbhit() and a timer rollover
to make sure that the function would not hang in an endless loop
if no <CR> was forthcoming. see the library for yourself:
is not hard to make the change i mention.........
gets() is a dangerous and IMHO pretty useless function
in terms of the risk to program reliability it represents.
Best used in Proteus but NOT in the real world !! |
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