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srkn
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| RS232 problem of two PIC communication |
 Posted: Sat Sep 19, 2009 1:05 pm |
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Hi all.
I'm trying to communicate 16f877 and 18f4550 with rs232. I just want to see they are communicating to start my real project but I am in trouble!
16f just sends a "sss" word with puts() function (when I press b7 button), and 18f takes it and prints "GELDI" on the lcd screen. However when I start the program and press the button 16f sends the word once, 18f gets in int_rda interrput and writes "GELDI" on LCD however it always gets in int_rda interrupt, although I send "sss" word only once.
Shortly 18f can not get out from int_rda interrupt.
Here is my 18f codes:
| Code: |
#include "C:\Documents and Settings\SER\Desktop\ockd\PIC\(19.09.2009) RS232 TRIAL 18f-16f\18f\18F_RS232.h"
#use fast_io(d)
#define use_portd_lcd TRUE
#include <lcd.c>
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,stop=1)
#int_rda
void rs232_kesme()
{
disable_interrupts(int_rda);
lcd_init();
delay_ms(1000);
printf(lcd_putc,"GELDI");
delay_ms(1000);
}
void main()
{
setup_adc_ports(NO_ANALOGS|VSS_VDD);
setup_adc(ADC_OFF);
setup_psp(PSP_DISABLED);
setup_spi(SPI_SS_DISABLED);
setup_wdt(WDT_OFF);
setup_timer_0(RTCC_INTERNAL);
setup_timer_1(T1_DISABLED);
setup_timer_2(T2_DISABLED,0,1);
setup_comparator(NC_NC_NC_NC);
setup_vref(FALSE);
set_tris_d(0x00);
output_d(0x00);
delay_ms(2000);
lcd_init();
printf(lcd_putc,"READY"); /to see PIC is ready
delay_ms(1000);
enable_interrupts(global);
while(1)
{
enable_interrupts(int_rda);
}
}
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I used to disable interrupt as shown but then it works only once. If I enable it as shown (as done in my book) when I enable the interrupt it again (immediately after enabling) gets in the int_rda interrupt (but there is no word send).
Here is my 16f code:
| Code: |
#include "C:\Documents and Settings\SERN\Desktop\Lod\PIC\(19.09.2009) RS232 TRIAL 18f-16f\16f\16F_RS232.h"
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,stop=1,timeout=10)
#int_RB
void kesme()
{
if(input(pin_b7))
{
puts("sss");
}
}
void main()
{
setup_adc_ports(NO_ANALOGS);
setup_adc(ADC_OFF);
setup_psp(PSP_DISABLED);
setup_spi(FALSE);
setup_timer_0(RTCC_INTERNAL|RTCC_DIV_1);
setup_timer_1(T1_DISABLED);
setup_timer_2(T2_DISABLED,0,1);
enable_interrupts(int_rb);
enable_interrupts(global);
}
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What can be the problem that I can not solve? |
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Ttelmah
Guest
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| Posted: Sat Sep 19, 2009 1:36 pm |
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INT_RDA, will occur for as long as a character is waiting in the serial RX buffer. You never read the receive character, so the buffer _will_ always have a character, once a character is received. Inside INT_RDA, you _must_ read the character....
The interrupt occurs for _each individual character_.
Best Wishes |
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bungee-
Joined: 27 Jun 2007
Posts: 206
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| Posted: Sat Sep 19, 2009 1:43 pm |
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And another problematic thing I noticed is that you use Delay in interrupt routine. That is BAD practice.
It would be better if you would use ISR just for receiving and if the condition (buffer = sss) would be true, then you set the flag to output the message on the LCD, and you would do that in main part of program. |
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srkn
Guest
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| Posted: Sun Sep 20, 2009 9:04 am |
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Thanks for quick replies.
I read the char value and cleared delays and write to LCD in main function that problem is solved, but some other problem occured.
If I send one char value with 16f, 18f takes irrelevant char values. And if I try to take string values, It can not finish taking the string value "aaa" and program can not pass gets() function.
Here are my new 18f codes:
| Code: |
#include "C:\Documents and Settings\S\Desktop\Lo\PIC\(19.09.2009) RS232 TRIAL 18f-16f\18f\18F_RS232.h"
#use fast_io(d)
#define use_portd_lcd TRUE
#include <lcd.c>
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,stop=1)
char yazi; // to take string I change it with the "char yazi[4];" command.
int i; // if it gets in interrupt, i becomes 1 to use in main function
#int_rda
void rs232_kesme()
{
disable_interrupts(int_rda);
yazi=getc() //if I take string I change it with the command: "gets(yazi);"
i=1; //to understand it get in the interrupt.
}
void main()
{
setup_adc_ports(NO_ANALOGS|VSS_VDD);
setup_adc(ADC_OFF);
setup_psp(PSP_DISABLED);
setup_spi(SPI_SS_DISABLED);
setup_wdt(WDT_OFF);
setup_timer_0(RTCC_INTERNAL);
setup_timer_1(T1_DISABLED);
setup_timer_2(T2_DISABLED,0,1);
setup_comparator(NC_NC_NC_NC);
setup_vref(FALSE);
set_tris_d(0x00);
output_d(0x00);
lcd_init();
printf(lcd_putc,"READY");
enable_interrupts(int_rda);
enable_interrupts(global);
while(1)
{
enable_interrupts(int_rda);
if(i==1) // if interrupt occured
{
i=0;
printf(lcd_putc,"%c",yazi); //If I take string values I change %c to %s
}
}
}
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Here is the command of 16f:
| Code: |
#include "C:\Documents and Settings\SE\Desktop\Loc\PIC\(19.09.2009) RS232 TRIAL 18f-16f\16f\16F_RS232.h"
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,stop=1,timeout=10)
#int_RB
void kesme()
{
if(input(pin_b7))
{
putc('b'); //If I send string value, I change it with the command: "puts("aaa");"
}
}
void main()
{
setup_adc_ports(NO_ANALOGS);
setup_adc(ADC_OFF);
setup_psp(PSP_DISABLED);
setup_spi(FALSE);
setup_timer_0(RTCC_INTERNAL|RTCC_DIV_1);
setup_timer_1(T1_DISABLED);
setup_timer_2(T2_DISABLED,0,1);
enable_interrupts(int_rb);
enable_interrupts(global);
}
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