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Chantry
Joined: 18 Jan 2011
Posts: 13
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| RFID Code Help |
 Posted: Mon Jan 31, 2011 2:50 pm |
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Hi!
I successfully programmed my PIC using the flexible LCD drivers available on here. My body of code looked like this:
| Code: | #include <16F88.H>
#fuses NOMCLR, INTRC_IO, NOBROWNOUT, NOWDT, NOPROTECT, NOPUT, NOLVP
#use delay(clock=8M)
//#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8,stream=ID12, ERRORS)
#define LCD_DB4 PIN_A6
#define LCD_DB5 PIN_A7
#define LCD_DB6 PIN_A0
#define LCD_DB7 PIN_A1
#define LCD_E PIN_A2
#define LCD_RS PIN_A3
#define LCD_RW PIN_A4
#define RFID_START_BYTE 0x0A
#define RFID_END_BYTE 0x0D
#include "flex_lcd2.h"
//============================================
void main(){
lcd_init(); // Always call this first.
output_high(PIN_B2);
lcd_putc("All persons to PS3");
lcd_putc("\nfor COD Black Ops");
while(1);
} |
I am now trying to connect my RFID reader (ID-12) to the RX on the pic so that I can read and display the tag ID on the LCD.
I found thread which uses the same module and posts some code:
http://www.ccsinfo.com/forum/viewtopic.php?t=41863
| Code: | #include <16F877A.H>
#FUSES NOWDT, HS, NOPUT, NOPROTECT, NODEBUG, NOBROWNOUT, NOLVP, NOCPD, NOWRT
#use delay(clock=20000000)
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8,stream=ID12, ERRORS)
#use rs232(baud=9600,parity=N,xmit=PIN_E0,rcv=PIN_E1,bits=8,stream=CPU, ERRORS)
#define RFID_START_BYTE 0x0A
#define RFID_END_BYTE 0x0D
void get_rfid_string()
{
int8 s[12];
unsigned int8 max=20;
unsigned int8 len;
char c;
// Wait for start byte
do
{
c = fgetc(ID12);
} while (c != RFID_START_BYTE);
// Receive data until END byte is received or buffer full
// correct for terminating zero
len=0;
s=0;
while ((c != RFID_END_BYTE) && (len < max))
{
c = fgetc(ID12);
s[len++] = c;
};
fprintf(CPU, "%s\n", s);
}
//3. Main program
VOID main()
{
DO {
get_rfid_string();
} WHILE(TRUE);
} |
If I wanted to try and integrate the LCD code into the RFID code, should it look something like this:
| Quote: | #include <16F88.H>
#fuses NOMCLR, INTRC_IO, NOBROWNOUT, NOWDT, NOPROTECT, NOPUT, NOLVP
#use delay(clock=8M)
#use rs232(baud=9600,parity=N,xmit=PIN_B5,rcv=PIN_B2,bits=8,stream=ID12, ERRORS)
#define RFID_START_BYTE 0x0A
#define RFID_END_BYTE 0x0D
void get_rfid_string()
{
lcd_init(); // Always call this first.
int8 s[12];
unsigned int8 max=20;
unsigned int8 len;
char c;
// Wait for start byte
do
{
c = fgetc(ID12);
} while (c != RFID_START_BYTE);
// Receive data until END byte is received or buffer full
// correct for terminating zero
len=0;
s=0;
while ((c != RFID_END_BYTE) && (len < max))
{
c = fgetc(ID12);
s[len++] = c;
};
// fprintf(CPU, "%s\n", s); //commented out
lcd_putc(CPU, "%s\n", s);
}
//3. Main program
VOID main()
{
DO {
get_rfid_string();
} WHILE(TRUE);
}
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I am really new to this so I'm sorry if its wrong. I won't be able to test it for a couple of days so I was hoping I could get some input and hopefully learn were I might have gone wrong.
Regards,
James |
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Chantry
Joined: 18 Jan 2011
Posts: 13
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| Posted: Tue Feb 01, 2011 10:25 am |
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Hi.
I would really appreciate help on this. I am trying to show the RFID serial string on the LCD.
I've worked on the code above and got it to this stage:
| Code: | #include <16F88.H>
#fuses INTRC_IO, NOBROWNOUT, NOWDT, NOPROTECT, NOPUT, NOLVP
#use delay(clock=8M)
#use rs232(baud=9600,parity=N,xmit=PIN_B5,rcv=PIN_B2,bits=8,stream=ID12, ERRORS)
#define LCD_DB4 PIN_A6
#define LCD_DB5 PIN_A7
#define LCD_DB6 PIN_A0
#define LCD_DB7 PIN_A1
#define LCD_E PIN_A2
#define LCD_RS PIN_A3
#define LCD_RW PIN_A4
#define RFID_START_BYTE 0x0A
#define RFID_END_BYTE 0x0D
#include "flex_lcd2.h"
int8 s[12];
void get_rfid_string()
{
unsigned int8 max=20;
unsigned int8 len;
char c;
// Wait for start byte
do
{
c = fgetc(ID12);
} while (c != RFID_START_BYTE);
// Receive data until END byte is received or buffer full
// correct for terminating zero
len=0;
s=0;
while ((c != RFID_END_BYTE) && (len < max))
{
c = fgetc(ID12);
s[len++] = c;
};
fputs (s,ID12);
}
//3. Main program
void main()
{
lcd_init(); // Always call this first.
// lcd_putc("Line Test");
do {
get_rfid_string();
} while(TRUE);
}
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It compiles file but I can't get anything to show up on the LCD when I move the tag to the RFID reader. Can anyone please tell me where I am going wrong?
James |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Feb 01, 2011 4:57 pm |
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The code below is a little weird. You have an array of 12 bytes for your
RFID string. Then you write incoming data bytes in the Tag to it, and you
do a length check against a value of 20. But your array is not 20 bytes
long. It's only 12. You have the possibility of writing past the end of array.
Normally a programmer would use the 'sizeof' operator to get the length
of the array for your comparison to 'len'.
| Quote: |
int8 s[12];
void get_rfid_string()
{
unsigned int8 max=20;
unsigned int8 len;
char c;
// Wait for start byte
do
{
c = fgetc(ID12);
} while (c != RFID_START_BYTE);
// Receive data until END byte is received or buffer full
// correct for terminating zero
len=0;
s=0;
while ((c != RFID_END_BYTE) && (len < max))
{
c = fgetc(ID12);
s[len++] = c;
};
fputs (s,ID12);
}
|
I don't know what the 's = 0' is doing ? Are you trying to load the array
with all 0's ? That's not how to do it. You can use the memset() function
to fill it with 0's.
I don't know what the fputs() line is supposed to do. Are you sending
the string back to the RFID unit ?
When you finally have your RFID data loaded into array s[], you need to
put a 0x00 byte at the end to convert it into a string. You need to add a
line of code to do that.
To display the string in array 's' on the LCD, you can use printf() and
re-direct the output to lcd_putc() as shown below. You need to clear
the array and set the cursor at the origin, before you display the string
This is done by sending '\f' to the lcd as shown below.
| Code: |
printf(lcd_putc, "\f%s", s); |
Last edited by PCM programmer on Tue Feb 01, 2011 5:12 pm; edited 1 time in total |
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Chantry
Joined: 18 Jan 2011
Posts: 13
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| Posted: Tue Feb 01, 2011 4:59 pm |
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Thank you very much for the advice on my code. I will use your help to hopefully get my unit working tomorrow.
- James |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Feb 01, 2011 5:21 pm |
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I added one additional comment on zeroing the 's' array while you
were posting your reply. |
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Chantry
Joined: 18 Jan 2011
Posts: 13
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| Posted: Tue Feb 01, 2011 5:25 pm |
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This is what I understand so far. The total RFID string which is sent is 20, but the RFID tag portion I need is only 12, this is why the max length is 20, but I understand that this might not be the best way of doing it.
I thought the RIFD might send a trailing 0 but it does not, so I will need to put this in.
fputs() was my attempt at sending the string to the LCD. I put this code in as a replacement as per your suggestion:
printf(lcd_putc, "\f%s", s);
However, I still do not get anything printed on the screen. I think I need to properly terminate the string before the string can be printed to the LCD?
p.s I will check the mem set function |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Feb 01, 2011 5:31 pm |
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All strings must have a terminator byte of 0x00 placed after the last of
ASCII bytes. |
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Chantry
Joined: 18 Jan 2011
Posts: 13
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| Posted: Wed Feb 02, 2011 12:18 pm |
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Hi,
Ive looked at this code and made a few tweaks. It still has the problem of the array size, but I think I have put a terminator on the string correctly and integrated your LCD code.
| Code: | #include <16F88.H>
#fuses INTRC_IO, NOBROWNOUT, NOWDT, NOPROTECT, NOPUT, NOLVP
#use delay(clock=8M)
#use rs232(baud=9600,parity=N,xmit=PIN_B5,rcv=PIN_B2,bits=8,stream=ID12, ERRORS)
#define LCD_DB4 PIN_A6
#define LCD_DB5 PIN_A7
#define LCD_DB6 PIN_A0
#define LCD_DB7 PIN_A1
#define LCD_E PIN_A2
#define LCD_RS PIN_A3
#define LCD_RW PIN_A4
#define RFID_START_BYTE 0x02
#define RFID_END_BYTE 0x03
#include "flex_lcd2.h"
int8 s[12];
void get_rfid_string()
{
unsigned int8 max=20;
unsigned int8 len;
char c;
// Wait for start byte
do
{
c = fgetc(ID12);
} while (c != RFID_START_BYTE);
// Receive data until END byte is received or buffer full
// correct for terminating zero
len=0;
while ((c != RFID_END_BYTE) && (len < max))
{
c = fgetc(ID12);
s[len++] = c;
s[len] = '\0'
};
printf(lcd_putc, "\f%s", s);
}
//3. Main program
void main()
{
lcd_init(); // Always call this first.
do {
get_rfid_string();
} while(TRUE);
} |
Could you confirm this please?
I still don't see anything on my LCD, but the RFID module does bleep (from BZ line) when I move a tag onto it, but I think I'm getting closer. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Wed Feb 02, 2011 5:00 pm |
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How do you know that the RFID program works ? Have you displayed
an RFID tag using RS-232 output to your PC ? I don't see any place in
your previous posts where you have proved that the RFID code works
with #use rs232(). |
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