CCS C Software and Maintenance Offers
FAQFAQ   FAQForum Help   FAQOfficial CCS Support   SearchSearch  RegisterRegister 

ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

CCS does not monitor this forum on a regular basis.

Please do not post bug reports on this forum. Send them to CCS Technical Support
Receiving problem from RS232 controlled device

 
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion
View previous topic :: View next topic  
Author Message
tunatopraktan



Joined: 19 Mar 2021
Posts: 13

View user's profile Send private message AIM Address

Receiving problem from RS232 controlled device
PostPosted: Tue Mar 23, 2021 4:30 am     Reply with quote
Hello friends,
I control a rs232 controlled device (a hdmi switcher) via rs232 protocol. While i am sending the code, everything is fine. But when i sent the code, the device send the feedback data to me. And when i want to receive these datas, the program stop.
When i take out the RDA_interrupts, (when i dont want to take feedback from device, my circuit is working good. But i need feedback data from device.

For example:
I can send "SET SW in4 out1\x0D\x0A" (set input 4 to output 1) serial code to device. After that the device send "SWin4 out1<CR><LF>" (input4 to output1 setted) serial data to me. But my device blocks. How can i get this serial data from device correctly ?

My code is below:
Code:

#include <16f877A.h>
#use delay(clock=20M)
#fuses HS, NOWDT, NOPUT, NOLVP, NOCPD, NOPROTECT, NODEBUG, NOBROWNOUT, NOWRT
#include <string.h>
#include <stdlib.h>

#use rs232 (baud=115200, xmit=pin_c6, rcv=pin_c7, parity=N, stop=1, errors, long_data)

char i;
int t, d, textsize;

char data[20];

#int_rda
void rs232_interrupt()
{ 
   for(t=0; t<10; t++)
   {
      data[t] = getch();
   }

}         


void main()
{       
   set_tris_b(0xFF);
   set_tris_c(0x00);
   delay_ms(50);
 
   enable_interrupts(GLOBAL); 
   enable_interrupts(int_rda);    // when i make disable the rda interrupts,
                                  // the program is working. But when i make
                                  // enable it, the program block

   while(1)
   {
      if(input(pin_b2) == 1)
      {
         printf("SET SW in3 out1\x0D\x0A");       
         delay_ms(50);
         output_high(pin_c2);
         delay_ms(100);
         output_low(pin_c2);
         delay_ms(20);
      }
      if(input(pin_b1) == 1)
      {
         printf("SET SW in4 out1\x0D\x0A");       
         delay_ms(50);
         output_high(pin_c1);
         delay_ms(100);
         output_low(pin_c1);
         delay_ms(20);
      }
      delay_ms(500);

      if(data[5] == "4")      // The "SWin4 out1<CR><LF>" serial code
                              // should come from device. And i asking data[5].
      {
         output_high(pin_c0);   
         delay_ms(500);
         output_low(pin_c0); 
      }   
   }         
}
temtronic



Joined: 01 Jul 2010
Posts: 9226
Location: Greensville,Ontario

View user's profile Send private message

PostPosted: Tue Mar 23, 2021 4:40 am     Reply with quote
Have a look at ex_sisr.c, the CCS supplied program that shows how to receive data using the RDA_ISR and a buffer.

It'll be in the EXAMPLES folder....
Ttelmah



Joined: 11 Mar 2010
Posts: 19511

View user's profile Send private message

PostPosted: Tue Mar 23, 2021 4:42 am     Reply with quote
An RS232 interrupt means _one_ byte is available for you to receive.
Just one.

You can't sit in the interrupt loading data.
The interrupt should load just one byte and increment the count and exit.
When the count gets to however many bytes should be in the complete
message then set a flag that the main code uses to say the message is
complete.
tunatopraktan



Joined: 19 Mar 2021
Posts: 13

View user's profile Send private message AIM Address

PostPosted: Thu Mar 25, 2021 7:41 am     Reply with quote
Ttelmah wrote:
An RS232 interrupt means _one_ byte is available for you to receive.
Just one.

You can't sit in the interrupt loading data.
The interrupt should load just one byte and increment the count and exit.
When the count gets to however many bytes should be in the complete
message then set a flag that the main code uses to say the message is
complete.


Thank you very much Ttelmah. Could you give a small example to me. I had solved my rs485 problem with your example.
temtronic



Joined: 01 Jul 2010
Posts: 9226
Location: Greensville,Ontario

View user's profile Send private message

PostPosted: Thu Mar 25, 2021 7:52 am     Reply with quote
again.....
Have a look at ex_sisr.c, the CCS supplied program that shows how to receive data using the RDA_ISR and a buffer.

It'll be in the EXAMPLES folder....
tunatopraktan



Joined: 19 Mar 2021
Posts: 13

View user's profile Send private message AIM Address

PostPosted: Thu Mar 25, 2021 8:03 am     Reply with quote
temtronic wrote:
again.....
Have a look at ex_sisr.c, the CCS supplied program that shows how to receive data using the RDA_ISR and a buffer.

It'll be in the EXAMPLES folder....


Thank you for your advice temtronic. Unfortunately i am new at MCU so i did not understand this example😣😣😣. why am i using bkbhit function.😩 If you explain basicly , i will be grateful🙏

Thanks for all your help
Ttelmah



Joined: 11 Mar 2010
Posts: 19511

View user's profile Send private message

PostPosted: Thu Mar 25, 2021 9:10 am     Reply with quote
Ex_SISR, stores the incoming data into a circular buffer.

In your main code, a byte is available when bkbhit says there is a byte.
You would need to read the bytes when they exist into a message string,
and then when you have a complete message (presumably marked by
something like a line feed), interpret what is in this buffer.
tunatopraktan



Joined: 19 Mar 2021
Posts: 13

View user's profile Send private message AIM Address

PostPosted: Fri Mar 26, 2021 2:41 am     Reply with quote
Ttelmah wrote:
Ex_SISR, stores the incoming data into a circular buffer.

In your main code, a byte is available when bkbhit says there is a byte.
You would need to read the bytes when they exist into a message string,
and then when you have a complete message (presumably marked by
something like a line feed), interpret what is in this buffer.



Hello friends,
I have integrated my code with "ex_sisr" example .
My code is shown below.

The problem is ; when i enable the rda interrupt ( enable_interrupts(int_rda); ) my circuit stop to send rs232 code too. Code loop is going on. only i can not send any rs232code.

Code:

#include <16f877A.h>
#use delay(clock=20M)
#fuses HS, NOWDT, NOPUT, NOLVP, NOCPD, NOPROTECT, NODEBUG, NOBROWNOUT, NOWRT
#include <string.h>
#include <stdlib.h>


#use rs232 (baud=115200, xmit=pin_c6, rcv=pin_c7, parity=N, stop=1, errors)

#define buffer_size 32
BYTE buffer[buffer_size];
BYTE next_in;
BYTE next_out;
BYTE data[32];


#int_rda
void serial_isr()
{ 
   int t;
   
   buffer[next_in] = getc();
   t = next_in;
   next_in = (next_in + 1) % buffer_size;
   if(next_in == next_out)
      next_in = t;                           // buffer full
}     

#define bkbhit (next_in != next_out)

BYTE bgetc()
   {
      BYTE c;
     
      while(!bkbhit);
      c = buffer[next_out];
      next_out = (next_out + 1) % buffer_size;
      return(c);
   }
   
void main()
{       
   set_tris_b(0xFF);
   set_tris_c(0x00);
   delay_ms(50);
 
//   enable_interrupts(int_rda);        // when i make this enable, the circuit does not send rs232 dat to device.
   enable_interrupts(GLOBAL);       
   
   do
   {
      delay_ms(1000);
      while(bkbhit)
         putc(bgetc());
         if(buffer[0] == 0x53)     // if buffer[0] is "S"   //receiver
         {
         output_high(pin_c1);
         delay_ms(50);
         output_low(pin_c1);
         }
           
       
       if(input(pin_b1) == 1)                     // sending data
       {
          printf("SET SW in4 out1\x0D\x0A");       
          delay_ms(50);
          output_high(pin_c2);
          delay_ms(100);
          output_low(pin_c2);
          delay_ms(20);
       }
   
       if(input(pin_b2) == 1)                      // sending data
       {
          printf("SET SW in3 out1\x0D\x0A");         
          delay_ms(50);
          output_high(pin_c2);
          delay_ms(100);
          output_low(pin_c2);
          delay_ms(20);
       }     
   }while (TRUE);
}
temtronic



Joined: 01 Jul 2010
Posts: 9226
Location: Greensville,Ontario

View user's profile Send private message

PostPosted: Fri Mar 26, 2021 5:31 am     Reply with quote
quick comment...

your code....
BYTE next_in;
BYTE next_out;

change to ...
BYTE next_in=0;
BYTE next_out=0;

You should ALWAYS preset any variable to a KNOWN value.
Pretty sure that RAM can be any value upon powerup. Others will know for sure, haven't looked at the datasheet....
I know CCS has #ZERO_RAM PPdirective, to put '0' in all RAM locations, based upon the PIC .
tunatopraktan



Joined: 19 Mar 2021
Posts: 13

View user's profile Send private message AIM Address

PostPosted: Fri Mar 26, 2021 6:01 am     Reply with quote
temtronic wrote:
quick comment...

your code....
BYTE next_in;
BYTE next_out;

change to ...
BYTE next_in=0;
BYTE next_out=0;

You should ALWAYS preset any variable to a KNOWN value.
Pretty sure that RAM can be any value upon powerup. Others will know for sure, haven't looked at the datasheet....
I know CCS has #ZERO_RAM PPdirective, to put '0' in all RAM locations, based upon the PIC .


I add #ZERO_RAM to my code. but same problem.
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

View user's profile Send private message

PostPosted: Fri Mar 26, 2021 6:17 am     Reply with quote
This is the problem:
Quote:
void main()
{
set_tris_b(0xFF);
set_tris_c(0x00);

You have caused the problem by setting the TRIS for Port C.

In section 10.0 of the 16F877A data sheet it says this:
Quote:
Bit SPEN (RCSTA<7>) and bits TRISC<7:6> have to be
set in order to configure pins RC6/TX/CK and RC7/RX/DT
as the Universal Synchronous Asynchronous Receiver
Transmitter

This means the TRIS for pins C6 and C7 have to be set = 1.
But you have set them = 0, causing the program to fail.

Delete the line shown in bold. Let the compiler handle the TRIS.
tunatopraktan



Joined: 19 Mar 2021
Posts: 13

View user's profile Send private message AIM Address

PostPosted: Fri Mar 26, 2021 9:41 am     Reply with quote
Thank you Master.
One problem was solved. Another point I have to solve is I can not take feedback from device. Do you have any advice about that?
Display posts from previous:   
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion All times are GMT - 6 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group