Cant open serial port properly ... I dont understand whats wrong ...

- D
- Doublehp
  
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posted
20 years ago

Mon, Feb 23, 2004 11:43 PM

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I received from motorola the following answer: "This customer use Linux and have trouble to send 0x0A or 0x0D, this is due to his Linux I/O driver. Metrowerks CodeWarrior for HC08 is run under Windowes OS and it works fine on 908JB8 without any trouble on send 0x0A or 0x0D down."

can someone untar

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read the file rs232.c and try to find whats wrong between lines 49 to 71 ?

I really dont understand what could make opening the port in a wrong mode ...

You dont really need to comile ... just read my last post, my logbook p29 and my source file.

Thanks for any help

- M
- Michael Anton
  
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posted
20 years ago

Tue, Feb 24, 2004 2:28 AM

You may need to specify the translation mode as binary, as I'm not sure what the default translation mode under Linux is.

Mike Anton

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- Doublehp
  
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posted
20 years ago

Tue, Feb 24, 2004 10:49 PM

after 2h of chat on IRC, someone said me that i forgot to enter nonOPOST mode, so I added line 70 with the proper line as described on http://www.easysw.mike/serial/serial.html

/* canonical raw input */ vars->serial->c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); vars->serial->c_lflag &= ~OPOST; vars->serial->c_cflag |= (CS8); /* use 8bit data */ // term_prop->c_cflag |= (CLOCAL | CREAD); tcsetattr(fd, TCSAFLUSH, vars->serial);

but I still had the same bug ... so that people offered that very horrible hack: I put

sprintf(stty,"stty -a < %s",vars->device); system(stty);

after tcsetattr

Q: why isnt the line with ~OPOST enough ???

- B
- Brian Dean
  
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posted
20 years ago

Wed, Feb 25, 2004 12:49 AM

OPOST needs to be applied to c_oflag (output modes), not c_lflag (local modes).

Cheers,

-Brian

--
Brian Dean, bsd@bdmicro.com
BDMICRO - MAVRIC & MAVRIC-II ATmega128 Based Dev Boards
http://www.bdmicro.com/

- D
- Doublehp
  
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posted
20 years ago

Thu, Feb 26, 2004 1:03 AM

You are right. Thank you all of you for your help

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- Wim Lewis
  
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posted
20 years ago

Thu, Feb 26, 2004 1:03 AM

Actually, this is setting *non*canonical input (turning off ICANON). "Canonical" input means translating the terminal's idea of CR into Unix's idea (0x0A). By default, the serial port is configured to talk to a terminal, so flags like that are turned on.

See "man termios" for all the gory details. Yo ucan probably get what you want with "raw" mode: call tcgetattr(), cfmakeraw(), and then tcsetattr() to apply the modified attributes back onto the serial device. cfmakeraw() does almost the same thing you're doing in the code snippet you posted, except it modifies a few more flags.

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      Wim Lewis , Seattle, WA, USA. PGP keyID 27F772C1