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ELCouz
Joined: 18 Jul 2007
Posts: 427
Location: Montreal,Quebec
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| Buffer error! |
 Posted: Thu Jul 17, 2014 6:11 pm |
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Hi,
I'm trying to catch commands with the rs232 pic hardware.
I want the buffer to start buffering when i send the start char ($) and stop buffering (* <- end delimiter) then display the data to the LCD.
Take a look to the modified code (yes, i'm using the circular buffer example from CCS)
| Code: |
#include <18F4685.h>
#FUSES HS,NOMCLR,NOLVP,NOPBADEN,BROWNOUT,BORV46,PUT
#use delay(clock=12M)
#use rs232(baud=9600, xmit=PIN_C6,rcv=PIN_C7,errors)
#include <lcd4x40.c>
#define BUFFER_SIZE 40
BYTE buffer[BUFFER_SIZE];
BYTE next_in = 0;
BYTE next_out = 0;
int8 buffermode = 0;
byte tmprx;
//****************************d*************************************************
char version[4] = "0.1"; /// change when releasing a new version !!!!!! <<<---
//*****************************************************************************
#int_rda
void serial_isr() {
int t;
tmprx = getc();
if (buffermode = 1){
buffer[next_in]=tmprx;
t=next_in;
next_in=(next_in+1) % BUFFER_SIZE;
if(next_in==next_out)
next_in=t; // Buffer full !!
}
if (tmprx == "$"){buffermode = 1;} //start the buffering
if (tmprx == "*"){buffermode = 3;} //buffer full an ready to be read
}
#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()
{
int8 i;
enable_interrupts(int_rda);
enable_interrupts(global);
lcd_init1();
delay_ms(100);
lcd_init2();
delay_ms(100);
while(1)
{
if (buffermode == 3) //buffer is ready then we read it!
{
for(i=0 ;i < 40; i++)
{
lcd_putc1(buffer[i]);
}
next_in = 0; //reset buffer data
next_out = 0; //reset buffer data
buffermode = 0; //set the wait for $ flag before buffering
}
}
}
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Why the $ and * serial char flags? Because I want other commands has well.
example:
$insert text here* = display lcd message
! = start a relay
% = led on
My code doesn't work i'm clueless why...
Btw, I've tested the lcd code before trying this more advanced code 
PCWHD 5.025
thank you very much!
_________________
Regards,
Laurent
-----------
Here's my first visual theme for the CCS C Compiler. Enjoy!
Last edited by ELCouz on Tue Jul 22, 2014 8:24 am; edited 2 times in total |
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jeremiah
Joined: 20 Jul 2010
Posts: 1355
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| Posted: Thu Jul 17, 2014 7:23 pm |
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Some basic issues:
you modified the ccs example. Your buffersize is now 40. This is a no no for that example. You either need to change the buffersize to a power of two or change the logic that uses the % sign (modulus operator) to be a faster implementation. Modulus operations are slow when not powers of two and thus shouldn't be used in an ISR if you intend to use a non power of two buffersize.
Your comparisons to $ and * are using " instead of ' like a character should. This will make your comparisons fail since you are comparing to a random address rather than the characters you want. |
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ELCouz
Joined: 18 Jul 2007
Posts: 427
Location: Montreal,Quebec
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| Posted: Thu Jul 17, 2014 7:26 pm |
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| jeremiah wrote: | Some basic issues:
you modified the ccs example. Your buffersize is now 40. This is a no no for that example. You either need to change the buffersize to a power of two or change the logic that uses the % sign (modulus operator) to be a faster implementation. Modulus operations are slow when not powers of two and thus shouldn't be used in an ISR if you intend to use a non power of two buffersize.
Your comparisons to $ and * are using " instead of ' like a character should. This will make your comparisons fail since you are comparing to a random address rather than the characters you want. |
Because my LCD is 40 char long. 64 bytes is too much no?
Oops thanks for pointing me out my typo...I'll try in a few hours when I have access to my board
thank you again!
_________________
Regards,
Laurent
-----------
Here's my first visual theme for the CCS C Compiler. Enjoy! |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19544
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| Posted: Fri Jul 18, 2014 1:09 am |
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The replacement code is:
| Code: |
//replace next_in=(next_in+1) % BUFFER_SIZE;
if (++next_in==BUFFER_SIZE)
next_in=0;
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It's one of those things that has been mentioned here many times, and should really have a warning in the example.
| Code: |
#include <18F4685.h>
#FUSES HS,NOMCLR,NOLVP,NOPBADEN,BROWNOUT,BORV46,PUT
#use delay(clock=12M)
#use rs232(baud=9600, xmit=PIN_C6,rcv=PIN_C7,errors)
#include <lcd4x40.c>
#define BUFFER_SIZE 40
BYTE buffer[BUFFER_SIZE];
BYTE next_in = 0;
BYTE next_out = 0;
int1 have_line=FALSE; //flag to main code
#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);
}
#int_rda
void serial_isr()
{
char tmprx; //don't make more things 'global' that are needed
int1 get_data=FALSE;
tmprx = getc();
if (get_data)
{
buffer[next_in]=tmprx;
t=next_in;
if (++next_in==BUFFER_SIZE)
next_in=0;
if(next_in==next_out)
next_in=t; // Buffer full !!
}
if (tmprx == '$')
get_data=TRUE; //start the buffering
if (tmprx == '*')
{
have_line=TRUE; //Flag main code that data is here
get_data=FALSE;
}
}
void main()
{
int8 i;
enable_interrupts(int_rda);
enable_interrupts(global);
delay_ms(300); //you want a delay _before_ init.
lcd_init1();
lcd_init2();
while(1)
{
if (have_data) //buffer is ready then we read it!
{
have_data=FALSE;
do
{
lcd_putc(bgetc());
} while bkbhit;
//There is no guarantee that you have 40 characters...
}
}
}
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Now comments:
1) The change away from '%'.
2) Character values for the tests, not strings.
3) You could have any number of characters between the $ and *. Counting for the 40 characters will not handle if this is not 40. That's the point of the bkbhit test.
4) The '%' test in the external code doesn't matter. It is though, slower and bulkier than the alternative test shown, when using a non binary buffer size.
5) Having a buffer larger than 40 characters will only matter if the message is ever longer than 40 characters.
6) There is no need to re-initialise the buffer.
7) There wants to be a delay _before_ calling lcd_init.
Your version flag is omitted from this. |
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ELCouz
Joined: 18 Jul 2007
Posts: 427
Location: Montreal,Quebec
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| Posted: Fri Jul 18, 2014 3:51 am |
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Thank you Ttelmah for your help!
The code had littles variables declaring errors so I've fixed them.
| Code: | #include <18F4685.h>
#FUSES HS,NOMCLR,NOLVP,NOPBADEN,BROWNOUT,BORV46,PUT
#use delay(clock=12M)
#use rs232(baud=9600, xmit=PIN_C6,rcv=PIN_C7,errors)
#include <lcd4x40.c>
#define BUFFER_SIZE 40
BYTE buffer[BUFFER_SIZE];
BYTE next_in = 0;
BYTE next_out = 0;
int1 have_line=FALSE; //flag to main code
**********************************************************************
#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);
}
#int_rda
void serial_isr()
{
int t;
char tmprx; //don't make more things 'global' that are needed
int1 get_data=FALSE;
tmprx = getc();
if (get_data)
{
buffer[next_in]=tmprx;
t=next_in;
if (++next_in==BUFFER_SIZE)
next_in=0;
if(next_in==next_out)
next_in=t; // Buffer full !!
}
if (tmprx == '$')
get_data=TRUE; //start the buffering
if (tmprx == '*')
{
have_line=TRUE; //Flag main code that data is here
get_data=FALSE;
}
}
void main()
{
enable_interrupts(int_rda);
enable_interrupts(global);
delay_ms(300);
lcd_init1();
lcd_init2();
printf(lcd_putc1,"Program ready");
while(1)
{
if (have_line) //buffer is ready then we read it!
{
have_line=FALSE;
do
{
lcd_putc1(bgetc());
} while bkbhit;
//There is no guarantee that you have 40 characters...
}
}
} |
While looking good on paper, running the program result nothing being display on the lcd.
After program ready, I've tried many combination possible... out of luck!
I feel that the have a line is never triggered.
ex: $12345656789* nothing
$abc* nothing
$ihavefortycharactersnowhehehethisislong* nothing
Also I've tested my usb to rs232 ttl cable (FTDI TTL-232R5V) work really good with the PIC.
_________________
Regards,
Laurent
-----------
Here's my first visual theme for the CCS C Compiler. Enjoy! |
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alan
Joined: 12 Nov 2012
Posts: 357
Location: South Africa
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| Posted: Fri Jul 18, 2014 4:23 am |
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This should
| Code: | | int1 get_data=FALSE |
probably be
| Code: | | static int1 get_data=FALSE |
Regards |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19544
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| Posted: Fri Jul 18, 2014 6:55 am |
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| Indeed it should, otherwise the variable gets cleared every time the routine is called. Hence data will never be 'got'..... |
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ELCouz
Joined: 18 Jul 2007
Posts: 427
Location: Montreal,Quebec
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| Posted: Sat Jul 19, 2014 8:12 am |
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It works !!!
EDIT: Also thanks to jeremiah for pointing me the obvious hehe
Some code fine tuning.
-Modified the ISR to skip the * char in the buffer
-Clear the lcd screen when a buffer dump happen
- Increased the buffer to 64 (had some garbage / missing char in the buffer)
| Code: |
#include <18F4685.h>
#FUSES HS,NOMCLR,NOLVP,NOPBADEN,BROWNOUT,BORV46,PUT
#use delay(clock=12M)
#use rs232(baud=9600, xmit=PIN_C6,rcv=PIN_C7,errors)
#include <lcd4x40.c>
#define BUFFER_SIZE 64
BYTE buffer[BUFFER_SIZE];
BYTE next_in = 0;
BYTE next_out = 0;
int1 have_line=FALSE; //flag to main code
#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);
}
#int_rda
void serial_isr()
{
int t;
char tmprx; //don't make more things 'global' that are needed
static int1 get_data=FALSE;
tmprx = getc();
if (get_data && tmprx != '*')
{
buffer[next_in]=tmprx;
t=next_in;
if (++next_in==BUFFER_SIZE)
next_in=0;
if(next_in==next_out)
next_in=t; // Buffer full !!
}
if (tmprx == '$')
get_data=TRUE; //start the buffering
if (tmprx == '*')
{
have_line=TRUE; //Flag main code that data is here
get_data=FALSE;
}
}
void main()
{
enable_interrupts(int_rda);
enable_interrupts(global);
delay_ms(300);
lcd_init1();
lcd_init2();
printf(lcd_putc1,"Program ready");
while(1)
{
if (have_line) //buffer is ready then we read it!
{
lcd_putc1('\f'); //clear the screen when receiving the buffer data
have_line=FALSE;
do
{
lcd_putc1(bgetc());
} while bkbhit;
//There is no guarantee that you have 40 characters...
}
}
}
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_________________
Regards,
Laurent
-----------
Here's my first visual theme for the CCS C Compiler. Enjoy! |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19544
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| Posted: Sat Jul 19, 2014 8:19 am |
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Flag the thread as 'solved'.
Well done... |
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ELCouz
Joined: 18 Jul 2007
Posts: 427
Location: Montreal,Quebec
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| Posted: Sat Jul 19, 2014 8:29 am |
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One last thing..
If I pass a short char command let say : @ = turn led on
What would be the best way to avoid conflict with the ISR buffer?
ex: prevent the [email protected]* being catched by the ISR command routine (turn the led on in middle of my text command)
I know everyone have their way to do it. But this is just to get me started in a correct manner.
thank you guys!
EDIT: i was thinking not using alphabetic command (ESC char, Del char etc)
_________________
Regards,
Laurent
-----------
Here's my first visual theme for the CCS C Compiler. Enjoy! |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19544
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| Posted: Sat Jul 19, 2014 8:50 am |
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Tests generically are very fast. The compiler just subtracts the 'test' value, and does a jump if the result is zero (or not zero, depending on the way round the test is done). Consider something like:
| Code: |
#int_rda
void serial_isr()
{
int t;
char tmprx; //don't make more things 'global' that are needed
static int1 get_data=FALSE;
tmprx = getc();
if (bit_test(temprx,7))
{
//Will only get here if the character is >127
//Test here for what you want, and do the operation
return; //exit so stuff does not go to buffer
}
if (get_data && tmprx != '*')
{
buffer[next_in]=tmprx;
t=next_in;
if (++next_in==BUFFER_SIZE)
next_in=0;
if(next_in==next_out)
next_in=t; // Buffer full !!
}
if (tmprx == '$')
get_data=TRUE; //start the buffering
if (tmprx == '*')
{
have_line=TRUE; //Flag main code that data is here
get_data=FALSE;
}
}
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This uses bit 7 of the character as a 'flag' to say this is a command. Then test for the actual character you want, and exit without ever going to the buffer code.
If you want the LED to go on/off when the character is received, then set/clear it in the interrupt. Otherwise set/clear a flag, and in the main code, after 'have_line' is seen, then set/clear the LED at this point. |
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ELCouz
Joined: 18 Jul 2007
Posts: 427
Location: Montreal,Quebec
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ELCouz
Joined: 18 Jul 2007
Posts: 427
Location: Montreal,Quebec
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| Posted: Mon Jul 21, 2014 7:19 pm |
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Updated the code to drive the 4x40 correctly...
| Code: | #include <18F4685.h>
#FUSES HS,NOMCLR,NOLVP,NOPBADEN,BROWNOUT,BORV46,PUT
#use delay(clock=12M)
#use rs232(baud=9600, xmit=PIN_C6,rcv=PIN_C7,errors)
#include <lcd4x40.c>
#define BUFFER_SIZE 196
BYTE buffer[BUFFER_SIZE];
BYTE next_in = 0;
BYTE next_out = 0;
int1 have_line=FALSE; //flag to main code
#define bkbhit (next_in!=next_out)
BYTE bgetc() {
BYTE c;
while(!bkbhit) ;
c=buffer[next_out];
next_out=(next_out+1) % BUFFER_SIZE;
return(c);
}
#int_rda
void serial_isr()
{
int t;
char tmprx; //don't make more things 'global' that are needed
static int1 get_data=FALSE;
tmprx = getc();
if (get_data && tmprx != '*')
{
buffer[next_in]=tmprx;
t=next_in;
if (++next_in==BUFFER_SIZE)
next_in=0;
if(next_in==next_out)
next_in=t; // Buffer full !!
}
if (tmprx == '$')
get_data=TRUE; //start the buffering
if (tmprx == '*')
{
have_line=TRUE; //Flag main code that data is here
get_data=FALSE;
}
}
void main()
{
int i;
enable_interrupts(int_rda);
enable_interrupts(global);
delay_ms(300);
lcd_init1();
lcd_init2();
printf(lcd_putc1,"Program ready");
while(1)
{
if (have_line) //buffer is ready then we read it!
{
lcd_putc1('\f'); //clear the screen when receiving the buffer data
lcd_putc2('\f');
have_line=FALSE;
do
{
for(i=0 ;i < 80; i++) {lcd_putc1(bgetc());} //split for the first LCD module
for(i=80 ;i < 160; i++) {lcd_putc2(bgetc());} //show the rest on the second module
} while bkbhit;
//There is no guarantee that you have 40 characters...
}
}
}
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This is the final working code
_________________
Regards,
Laurent
-----------
Here's my first visual theme for the CCS C Compiler. Enjoy! |
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ELCouz
Joined: 18 Jul 2007
Posts: 427
Location: Montreal,Quebec
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| Posted: Mon Jul 21, 2014 11:33 pm |
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One last question, I promise...
Some times the buffer order get screwed up.
What would be the procedure to reinitialize the buffer?
I've tried resetting the buffer with
| Code: | next_in = 0; //reset buffer data
next_out = 0; //reset buffer data |
Doesn't seem to work...
It would also help me reset the buffer when it miss the * end char so the buffer ISR would stop capturing after 160 chars (kind of a buffer timeout)
Any ideas??
thanks!
_________________
Regards,
Laurent
-----------
Here's my first visual theme for the CCS C Compiler. Enjoy! |
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