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nurquhar
Joined: 05 Aug 2006 Posts: 149 Location: Redditch, UK
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Why does #use rs232 ENABLE=PIN not work with puts or printf |
Posted: Sun Oct 08, 2006 1:08 am |
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I have an odd problem with the way puts and printf are working when using the #use rs232 ENABLE feature. Basically I can see the output on Hyperterminal from the putc() but a string sent with puts() or printf() sends blanks. I am using SP485REN chip with B0 connected to the DE and /RE inputs.
The following prog compiled with 3.249 gives the following output.
Code: |
// CPU Clock Freq
#define FOSC 20000000
#define BAUDRT 9600
#include <16F876A.h>
#include <stdio.h>
#fuses HS,NOWDT,PUT,NOPROTECT,NOBROWNOUT,NOLVP,NOCPD,NOWRT
#use delay(clock=FOSC)
#use rs232 (baud=BAUDRT, xmit=PIN_C6, rcv=PIN_C7, PARITY=N, BITS=8, ENABLE=PIN_B0)
void main()
{
unsigned int ch ;
putc('O') ;
putc('k') ;
putc('\r') ;
putc('\n') ;
puts("Hello from Puts") ;
putc('H') ;
putc('e') ;
putc('l') ;
putc('l') ;
putc('o') ;
putc('\r') ;
putc('\n') ;
while(1) {
if (kbhit()) {
ch = getc() ;
putc(ch) ;
if (ch == 0x31) {
puts("Puts a long string to test the output") ;
putc('N') ;
putc('o') ;
putc(' ') ;
putc('1') ;
putc('\r') ;
putc('\n') ;
}
}
}
}
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The output on the terminal with me typing 1,2,3
Quote: | Ok
ts
Hello
1ut
No 1
23 |
I thought puts()/printf used putc at the bottom level ? However it seems to be doing the enable in a different way.
Any ideas ? |
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nurquhar
Joined: 05 Aug 2006 Posts: 149 Location: Redditch, UK
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Posted: Sun Oct 08, 2006 1:29 am |
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I made a small mod and used my own puts which works ! Whats wrong with CCS version ?
Code: | // CPU Clock Freq
#define FOSC 20000000
#define BAUDRT 9600
#include <16F876A.h>
#include <stdio.h>
#fuses HS,NOWDT,PUT,NOPROTECT,NOBROWNOUT,NOLVP,NOCPD,NOWRT
#use delay(clock=FOSC)
#use rs232 (baud=BAUDRT, xmit=PIN_C6, rcv=PIN_C7, PARITY=N, BITS=8, ENABLE=PIN_B0)
char buf[40] ;
void myputs(char *str)
{
for(; *str != 0 ; str++) {
putc(*str) ;
}
putc('\r') ;
putc('\n') ;
}
void main()
{
unsigned int ch ;
putc('O') ;
putc('k') ;
putc('\r') ;
putc('\n') ;
// puts("Hello from Puts") ;
strcpy(buf, "Hello from Puts") ;
myputs(buf) ;
putc('H') ;
putc('e') ;
putc('l') ;
putc('l') ;
putc('o') ;
putc('\r') ;
putc('\n') ;
while(1) {
if (kbhit()) {
ch = getc() ;
putc(ch) ;
if (ch == 0x31) {
// puts("Puts a long string to test the output") ;
strcpy(buf, "Puts a long string to test the output") ;
myputs(buf) ;
putc('N') ;
putc('o') ;
putc(' ') ;
putc('1') ;
putc('\r') ;
putc('\n') ;
}
}
}
} |
Output for 1,2,3
Quote: | Ok
Hello from Puts
Hello
1Puts a long string to test the output
No 1
23 |
[/code] |
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PCM programmer
Joined: 06 Sep 2003 Posts: 21708
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Posted: Sun Oct 08, 2006 2:16 pm |
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puts() is a macro that calls printf. Here's the macro definition
from stdlib.h.
Code: | #define puts(s) {printf(s); putchar(13); putchar(10);} |
Here's the stdlib.h file location: c:\program files\picc\drivers\stdio.h
So the problem is in printf.
Here's a report in April 2005 of the same problem.
http://www.ccsinfo.com/forum/viewtopic.php?t=22421
It appears that 'enable' only works with putc(). So one way to do
a work-around would be to use the re-direction feature of the CCS
printf() function, and send the output to putc. Example:
Code: |
#include <16F877.h>
#fuses XT, NOWDT, NOPROTECT, PUT, BROWNOUT, NOLVP
#use delay(clock=4000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, Enable=PIN_B0, ERRORS)
my_putc(char c)
{
putc(c);
}
//===================================
void main()
{
printf(my_putc, "Hello World");
while(1);
} |
I looked at the .LST file, and this does work. |
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nurquhar
Joined: 05 Aug 2006 Posts: 149 Location: Redditch, UK
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Posted: Mon Oct 09, 2006 12:52 am |
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Dear PCM
Thanks for confirming what I suspected. ie its a long standing CCS bug. Re-directing through "myputc" with printf(myputc, "xxx") is certanily a good work around, however it would be much better if CCS fixed it. I am guesing the fix will consume another valuable stack level. Especialy if you only have an level 8 stack to start with !
I'll post it as bug to CCS, you never know if may get fixed by April 2007. |
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