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Interesting problem sending long data

 
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sophiadoll



Joined: 11 Sep 2009
Posts: 3

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Interesting problem sending long data
PostPosted: Fri Sep 11, 2009 10:33 am     Reply with quote

I am new to CCS. I am trying to send data from a master to a receiver. I am sending two things, the first is the character 'A', the second is a counter.

I want to send it as long data because I went to be able to differentiate the type of data by setting an extra bit on the data packet that is the character 'A'.

When I send data I receive something like this:

001000001 (Character 'A')
100000000 (Counter)

It appears the bit i set on A is being set on the counter instead. I imagine it has something to do with the way getc() works. Below are my codes.

Sender
Code:

#include <18f252.h>

#fuses HS, NOWDT, NOLVP, NOBROWNOUT, NOPROTECT, PUT
#use delay(clock = 10000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, bits=9, long_data, stream=PC)

#define LCD_RS_PIN         PIN_B0
#define LCD_RW_PIN         PIN_B1
#define LCD_ENABLE_PIN     PIN_B2
#define LCD_DATA0          PIN_B4
#define LCD_DATA1          PIN_B5
#define LCD_DATA2          PIN_B6
#define LCD_DATA3          PIN_B7   

#include <lcd.h>

#define DE   PIN_C4   
#define RE   PIN_C5
#define DI   PIN_C6
#define RO   PIN_C7

void main()
{
   int16 i;
   int j = 0;
   lcd_init();
   output_high(DE);

   while(true)
   {
      i = ((int16)0x100|'A');
      printf(lcd_putc, "\f%ld", i);
      fputc(i, PC);
      delay_ms(200);
      lcd_gotoxy(1,2);
      fputc(j, PC);
      printf(lcd_putc, "%d", j);
      j++;
      delay_ms(800);
   }
}


Receiver
Code:

#include <18f252.h>

#fuses HS, NOWDT, NOLVP, NOBROWNOUT, NOPROTECT, PUT
#use delay(clock = 10000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, bits=9, long_data, stream=PC)

#define LCD_RS_PIN         PIN_B0
#define LCD_RW_PIN         PIN_B1
#define LCD_ENABLE_PIN     PIN_B2
#define LCD_DATA0          PIN_B4
#define LCD_DATA1          PIN_B5
#define LCD_DATA2          PIN_B6
#define LCD_DATA3          PIN_B7   

#include <lcd.h>

#define DE   PIN_C4   
#define RE   PIN_C5
#define DI   PIN_C6
#define RO   PIN_C7

#INT_RDA
void in()
{   
   int16 j, k;
   j = getc();
   printf(lcd_putc,"\f");
   printf(lcd_putc, "%u", bit_test(j,8));
   printf(lcd_putc, "%u", bit_test(j,7));
   printf(lcd_putc, "%u", bit_test(j,6));
   printf(lcd_putc, "%u", bit_test(j,5));
   printf(lcd_putc, "%u", bit_test(j,4));
   printf(lcd_putc, "%u", bit_test(j,3));
   printf(lcd_putc, "%u", bit_test(j,2));
   printf(lcd_putc, "%u", bit_test(j,1));
   printf(lcd_putc, "%u", bit_test(j,0));
      
   k = getc();
   lcd_gotoxy(1,2);
   printf(lcd_putc, "%u", bit_test(k,8));
   printf(lcd_putc, "%u", bit_test(k,7));
   printf(lcd_putc, "%u", bit_test(k,6));
   printf(lcd_putc, "%u", bit_test(k,5));
   printf(lcd_putc, "%u", bit_test(k,4));
   printf(lcd_putc, "%u", bit_test(k,3));
   printf(lcd_putc, "%u", bit_test(k,2));
   printf(lcd_putc, "%u", bit_test(k,1));
   printf(lcd_putc, "%u", bit_test(k,0));
}

void main()
{
   enable_interrupts(INT_RDA);
   enable_interrupts(GLOBAL);
   lcd_init();
   output_low(DE);
   output_low(RE);

   while(true)
   {
      output_low(PIN_B3);
      delay_ms(200);
      output_high(PIN_B3);
      delay_ms(200);
   }
}
filjoa



Joined: 04 May 2008
Posts: 260

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PostPosted: Fri Sep 11, 2009 11:08 am     Reply with quote

Hi

I don't understand correctly your problem but, I have this example for comunicated with an GPS see if this help you..

Quote:

#int_rda
void rda_isr(void)
{
char c, string[61];
int i,k;

c=getc(gpsport);

if (c=='C')
{
i=0;
k=0;
do
{
c=getc(gpsport);
i++;
string[i]=c;
}while(c!='*');
i=i-1;
fprintf(tlmport, "array size: %u\n\r",i);

//$GPRMC,161229.000,A,3723.2475,N,12158.3416,W,0.13,309.62,120598,,*10
for(k=2;k<=12;k++)
{
fprintf(tlmport, "time: %c\n\r",string[k]);
}
}

}

void main ()
{
enable_interrupts(INT_RDA);
enable_interrupts(GLOBAL);

while(1)
{
printf("wait for first character \n\r");
delay_ms(1000);
}

}


kind regards
sophiadoll



Joined: 11 Sep 2009
Posts: 3

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PostPosted: Fri Sep 11, 2009 1:05 pm     Reply with quote

Let me explain myself better.

I am trying to send 9 bits of data. There are two data packets. The first is the character 'A' with the ninth bit set. The ascii value for the character 'A' is 65 which translates to 1000001. Therefore with the ninth bit set the receiver should see 101000001. The second data packet is just a counter in binary, starting from 000000000 then 000000001 then 000000010 etc...

So I want to see on my LCD something like this:

101000001
000000000

and each second the second line should increment as so:

101000001
000000001

101000001
000000010

101000001
000000011

101000001
000000100

And so on. But what I'm getting instead is the ninth bit set on that second line (counter) as shown below and not on the character line

001000001 (character line)
100000000 (counter line)

001000001
100000001

001000001
100000010

001000001
100000011

I hope I explained myself better. Thanks in advance for any help.
asmboy



Joined: 20 Nov 2007
Posts: 2128
Location: albany ny

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PostPosted: Fri Sep 11, 2009 6:38 pm     Reply with quote

is there some reason you don't send simply send 8 bit ascii, exactly as you want to display it on the LCD ???


like send literally

"Annnn"<cr> where nnn is the ascii presentation of the number
and you just receive it in a string buffer and
stream it thru to the LCD as you receive it ?

been there - done that - got a wardrobe od tee shirts for it

i think U R MAKING IT HARDER THAN IT HAS TO BE


Very Happy
sophiadoll



Joined: 11 Sep 2009
Posts: 3

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PostPosted: Mon Sep 14, 2009 8:33 am     Reply with quote

Yes there is a reason why I don't just literally send the 8 bit ascii character. I am designing my own version of a communication protocol. On certain data packets I need to set a ninth bit to be able to differentiate types of data, and I need to be able to check that ninth bit. That is the reason I am outputting my data in binary so that I can check what is happening bit by bit.

I believe the problem lies in the way I am declaring the #use rs232 (...bits = 9, long data). From the manual I understood I could send 16 bit data using the long data parameter. Does anyone have any samples or a good explanation on who to properly send and receive 16-bit data?
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Mon Sep 14, 2009 12:03 pm     Reply with quote

You don't need #int_rda interrupts to do the test. Get rid of the #int_rda
and put the code in main(). Get rid of the code that enables interrupts.
Also, don't do a continuous test. Just send two 9-bit words, then stop.
See if you can receive just those two words.

In other words, simplify everything down to almost nothing. Make that
work. Then add complexity.
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