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Annotation of MiNT/doc/modem.doc, revision 1.1

1.1     ! root        1: Here are some notes on writing device drivers; before reading
        !             2: 
        !             3: them, you should familiarize yourself with the information in
        !             4: 
        !             5: "filesys.doc", especially the material on device drivers.
        !             6: 
        !             7: 
        !             8: 
        !             9: Serial Port Device Drivers
        !            10: 
        !            11: 
        !            12: 
        !            13: Serial port device drivers should recognize the
        !            14: 
        !            15: following ioctl calls:
        !            16: 
        !            17: (here "f" is always a FILEPTR referring to an open
        !            18: 
        !            19: file on the device)
        !            20: 
        !            21: 
        !            22: 
        !            23: 
        !            24: 
        !            25: ioctl(f, TIOCIBAUD, long *r):
        !            26: 
        !            27: 
        !            28: 
        !            29: Set input speed. "r" is a pointer to a 32 bit value, and is both an
        !            30: 
        !            31: input and output parameter. If *r is > 0, it represents the value
        !            32: 
        !            33: to which the serial port's input speed should be set. This value
        !            34: 
        !            35: is a long word representation of the speed in bits per second,
        !            36: 
        !            37: e.g. to set 9600 bits per second *r should be 9600L.
        !            38: 
        !            39: If *r is 0, it indicates that DTR should be dropped.
        !            40: 
        !            41: If *r is < 0, the call is an inquiry call only.
        !            42: 
        !            43: 
        !            44: 
        !            45: On return, *r is set to the value of the input speed before the
        !            46: 
        !            47: ioctl call was made. If, for some reason, this value is unknown,
        !            48: 
        !            49: *r is set to -1L.
        !            50: 
        !            51: 
        !            52: 
        !            53: Returns:
        !            54: 
        !            55: 0 on success
        !            56: 
        !            57: ERANGE if the requested input speed is not available. In this case,
        !            58: 
        !            59: the next lowest legal input speed available is returned in *r.
        !            60: 
        !            61: 
        !            62: 
        !            63: 
        !            64: 
        !            65: 
        !            66: 
        !            67: ioctl(f, TIOCOBAUD, long *r):
        !            68: 
        !            69: 
        !            70: 
        !            71: Set output speed. "r" is a pointer to a 32 bit value, and is both an
        !            72: 
        !            73: input and output parameter. If *r is > 0, it represents the value
        !            74: 
        !            75: to which the serial port's output speed should be set. This value
        !            76: 
        !            77: is a long word representation of the speed in bits per second,
        !            78: 
        !            79: e.g. to set 9600 bits per second *r should be 9600L.
        !            80: 
        !            81: If *r is 0, it indicates that the device should be hung up, i.e.
        !            82: 
        !            83: that DTR should no longer be asserted.
        !            84: 
        !            85: If *r is < 0, no change is to be made to the output speed.
        !            86: 
        !            87: 
        !            88: 
        !            89: On return, *r is set to the value of the output speed before the
        !            90: 
        !            91: ioctl call was made. If, for some reason, this value is unknown,
        !            92: 
        !            93: *r is set to -1L.
        !            94: 
        !            95: 
        !            96: 
        !            97: Returns:
        !            98: 
        !            99: 0 on success
        !           100: 
        !           101: ERANGE if the requested output speed is not available. In this case,
        !           102: 
        !           103: the next lowest legal output speed available is returned in *r.
        !           104: 
        !           105: 
        !           106: 
        !           107: Note: For many devices both the input and output speeds must always be
        !           108: 
        !           109: the same. For such devices, TIOCIBAUD and TIOCOBAUD may affect both
        !           110: 
        !           111: input and output speed.
        !           112: 
        !           113: 
        !           114: 
        !           115: 
        !           116: 
        !           117: 
        !           118: 
        !           119: ioctl(f, TIOCSBRK, dummy):
        !           120: 
        !           121: 
        !           122: 
        !           123: Causes a BREAK condition to be set on the output line.
        !           124: 
        !           125: Returns:
        !           126: 
        !           127: 0 on success
        !           128: 
        !           129: EINVFN if the serial port cannot send BREAK
        !           130: 
        !           131: 
        !           132: 
        !           133: 
        !           134: 
        !           135: 
        !           136: 
        !           137: ioctl(f, TIOCCBRK, dummy)
        !           138: 
        !           139: 
        !           140: 
        !           141: Causes any existing BREAK condition to be cleared.
        !           142: 
        !           143: Returns:
        !           144: 
        !           145: 0 on success
        !           146: 
        !           147: EINVFN if the serial port cannot send BREAK
        !           148: 
        !           149: 
        !           150: 
        !           151: 
        !           152: 
        !           153: 
        !           154: 
        !           155: ioctl(f, TIOCGFLAGS, short *flags)
        !           156: 
        !           157: 
        !           158: 
        !           159: Get the terminal control flags bits. 16 bit flag word
        !           160: 
        !           161: pointed to by "flags" is set to reflect the current
        !           162: 
        !           163: terminal state, as follows:
        !           164: 
        !           165: 
        !           166: 
        !           167: TF_STOPBITS    0x0003
        !           168: 
        !           169: The two low order bits describe the stop bits:
        !           170: 
        !           171: 0x0000 illegal -- attempts to set this value are
        !           172: 
        !           173:        ignored
        !           174: 
        !           175: 0x0001 1 stop bit
        !           176: 
        !           177: 0x0002 1.5 stop bits
        !           178: 
        !           179: 0x0003 2 stop bits
        !           180: 
        !           181: 
        !           182: 
        !           183: TF_CHARBITS    0x000C
        !           184: 
        !           185: The next two bits describe the number of bits
        !           186: 
        !           187: transmitted per character:
        !           188: 
        !           189: 0x0000 8 bits per character
        !           190: 
        !           191: 0x0004 7 bits per character
        !           192: 
        !           193: 0x0008 6 bits per character
        !           194: 
        !           195: 0x000C 5 bits per character
        !           196: 
        !           197: 
        !           198: 
        !           199: The final nybble contains miscellaneous flags:
        !           200: 
        !           201: T_TANDEM       0x1000          ^S/^Q flow control active
        !           202: 
        !           203: T_RTSCTS       0x2000          RTS/CTS flow control active
        !           204: 
        !           205: T_EVENP                0x4000          even parity enabled
        !           206: 
        !           207: T_ODDP         0x8000          odd parity enabled
        !           208: 
        !           209:        (note: T_EVENPAR and T_ODDPAR are mutually exclusive)
        !           210: 
        !           211: 
        !           212: 
        !           213: All other bits are reserved, and should be set to 0.
        !           214: 
        !           215: 
        !           216: 
        !           217: Returns:
        !           218: 
        !           219: 0 on success
        !           220: 
        !           221: 
        !           222: 
        !           223: 
        !           224: 
        !           225: 
        !           226: 
        !           227: ioctl(f, TIOCSFLAGS, short *flags)
        !           228: 
        !           229: 
        !           230: 
        !           231: Set the terminal control flags (see the description
        !           232: 
        !           233: of TIOCGFLAGS for details) based on the values in the
        !           234: 
        !           235: word pointed to by "flags".
        !           236: 
        !           237: 
        !           238: 
        !           239: Returns:
        !           240: 
        !           241: 0 on success
        !           242: 
        !           243: ERANGE if an illegal or unsupported combination of flags
        !           244: 
        !           245:  is detected.
        !           246: 
        !           247: 
        !           248: 
        !           249: 
        !           250: 
        !           251: INTERFACE WITH EXISTING TIOCSETP/TIOCGETP CALLS:
        !           252: 
        !           253: 
        !           254: 
        !           255: The MiNT kernel will automatically make appropriate
        !           256: 
        !           257: TIOCIBAUD, TIOCOBAUD, TIOCGFLAGS, and TIOCSFLAGS calls
        !           258: 
        !           259: whenever a TIOCSETP or TIOCGETP Fcntl is made on a
        !           260: 
        !           261: terminal. The kernel will convert a Unix style baud
        !           262: 
        !           263: specification into a MiNT style one, as follows:
        !           264: 
        !           265: 
        !           266: 
        !           267: value of sg_ispeed or       value sent to
        !           268: 
        !           269:      sg_ospeed                  driver
        !           270: 
        !           271: #define B0     0                   0L
        !           272: 
        !           273: #define B50    1                  50L
        !           274: 
        !           275: #define B75    2                  75L
        !           276: 
        !           277: #define B110   3                 110L
        !           278: 
        !           279: #define B134   4                 134L
        !           280: 
        !           281: #define B150   5                 150L
        !           282: 
        !           283: #define B200   6                 200L
        !           284: 
        !           285: #define B300   7                 300L
        !           286: 
        !           287: #define B600   8                 600L
        !           288: 
        !           289: #define B1200  9                1200L
        !           290: 
        !           291: #define B1800  10               1800L
        !           292: 
        !           293: #define B2400  11               2400L
        !           294: 
        !           295: #define B4800  12               4800L
        !           296: 
        !           297: #define B9600  13               9600L
        !           298: 
        !           299: #define B19200 14              19200L
        !           300: 
        !           301: #define B38400 15              38400L (*)
        !           302: 
        !           303: 
        !           304: 
        !           305: anything else                     -1L
        !           306: 
        !           307: 
        !           308: 
        !           309: 
        !           310: 
        !           311: (*) 38400 baud is not supported by the built
        !           312: 
        !           313: in device drivers, but may be by external drivers
        !           314: 
        !           315: 
        !           316: 
        !           317: If a speed other than those listed above is desired, the
        !           318: 
        !           319: TIOCIBAUD and/or TIOCOBAUD Fcntls should be used directly.
        !           320: 

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