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DGB(4)		       BSD/i386	Kernel Interfaces Manual		DGB(4)

     dgb -- DigiBoard intelligent serial cards driver

     options NDGBPORTS=8
     device dgb0 at isa? port 0x220 iomem 0xfc0000 iosiz ? flags 0x0
     All values	are just examples.

     The NDGBPORTS option defines the total number of ports on all cards in-
     stalled in	the system.  When not defined the number is computed:

	 default NDGBPORTS = number_of_described_DigiBoard_cards * 16

     If	it is less than	the actual number of ports the system will be able to
     use only the first	NDGBPORTS ports.  If it	is greater then	all ports will
     be	usable but some	memory will be wasted.

     Meaning of	flags:
     0x0001  use alternate pinout (exchange DCD	and DSR	lines)
     0x0002  don't use 8K window mode of PC/Xe

     Device numbering:
       CCard number
	 mmmmmmmmajor number
		    PPPPPort number

     The dgb driver provides support for DigiBoard PC/Xe and PC/Xi series in-
     telligent serial multiport	cards with asynchronous	interfaces based on
     the EIA RS-232C (CCITT V.24) standard.

     Input and output for each line may	set to one of following	baud rates;
     50, 75, 110, 134.5, 150, 300, 600,	1200, 1800, 2400, 4800,	9600, 19200,
     38400, 57600, or for newer	versions of cards 115200.

     The driver	doesn't	use any	interrupts, it is "polling-based".  This means
     that it uses clock	interrupts instead of interrupts generated by Digi-
     Board cards and checks the	state of cards 25 times	per second.  This is
     practical because the DigiBoard cards have	large input and	output buffers
     (more than	1Kbyte per port) and hardware that allows efficiently finding
     the port that needs attention.  The only problem seen with	this policy is
     slower SLIP and PPP response.

     Each line in the kernel configuration file	describes one card, not	one
     port as in	the sio(4) driver.

     The flags keyword may be used on each "device dgb"	line in	the kernel
     configuration file	to change the pinout of	the interface or to use	new
     PC/Xe cards which can work	with an	8K memory window in compatibility mode
     (with a 64K memory	window).  Note that using 8K memory window doesn't
     mean shorter input/output buffers,	it means only that all buffers will be
     mapped to the same	memory address and switched as needed.

     The port value must be the	same as	the port set on	the card by jumpers.
     For PC/Xi cards the same rule is applicable to the	iomem value.  It must
     be	the same as the	memory address set on the card by jumpers.  For	PC/Xe
     cards there is no need to use jumpers for this purpose.  In fact there
     are no jumpers to do it.  Just write the address you want as the iomem
     value in kernel config file and the card will be programmed to use	this

     The same range of memory addresses	may be used for	all the	DigiBoards in-
     stalled (but not for any other card or real memory).  DigiBoards with a
     large amount of memory (256K or 512K and perhaps even 128K) must be
     mapped to memory addresses	outside	of the first megabyte.	If the com-
     puter has more than 15 megabytes of memory	then there is no free address
     space outside of the first	megabyte where such DigiBoards can be mapped.
     In	this case you may need to reduce the amount of memory in the computer.
     But many machines provide a better	solution.  They	have the ability to
     "turn off"	the memory in the 16th megabyte	(addresses 0xF00000 -
     0xFFFFFF) using the BIOS setup.  Then the DigiBoard's address space can
     be	set to this "hole".

     Serial ports controlled by	the dgb	driver can be used for both "callin"
     and "callout".  For each port there is a callin device and	a callout de-
     vice.  The	minor number of	the callout device is 128 higher than that of
     the corresponding callin port.  The callin	device is general purpose.
     Processes opening it normally wait	for carrier and	for the	callout	device
     to	become inactive.  The callout device is	used to	steal the port from
     processes waiting for carrier on the callin device.  Processes opening it
     do	not wait for carrier and put any processes waiting for carrier on the
     callin device into	a deeper sleep so that they do not conflict with the
     callout session.  The callout device is abused for	handling programs that
     are supposed to work on general ports and need to open the	port without
     waiting but are too stupid	to do so.

     The dgb driver also supports an initial-state and a lock-state control
     device for	each of	the callin and the callout "data" devices.  The	minor
     number of the initial-state device	is 32 higher than that of the corre-
     sponding data device.  The	minor number of	the lock-state device is 64
     higher than that of the corresponding data	device.	 The termios settings
     of	a data device are copied from those of the corresponding initial-state
     device on first opens and are not inherited from previous opens.  Use
     stty(1) in	the normal way on the initial-state devices to program initial
     termios states suitable for your setup.

     The lock termios state acts as flags to disable changing the termios
     state.  E.g., to lock a flag variable such	as CRTSCTS, use	"stty crtscts"
     on	the lock-state device.	Speeds and special characters may be locked by
     setting the corresponding value in	the lock-state device to any nonzero

     Correct programs talking to correctly wired external devices work with
     almost arbitrary initial states and no locking, but other setups may ben-
     efit from changing	some of	the default initial state and locking the
     state.  In	particular, the	initial	states for non (POSIX) standard	flags
     should be set to suit the devices attached	and may	need to	be locked to
     prevent buggy programs from changing them.	 E.g., CRTSCTS should be
     locked on for devices that	support	RTS/CTS	handshaking at all times and
     off for devices that don't	support	it at all.  CLOCAL should be locked on
     for devices that don't support carrier.  HUPCL may	be locked off if you
     don't want	to hang	up for some reason.  In	general, very bad things hap-
     pen if something is locked	to the wrong state, and	things should not be
     locked for	devices	that support more than one setting.  The CLOCAL	flag
     on	callin ports should be locked off for logins to	avoid certain security
     holes, but	this needs to be done by getty if the callin port is used for
     anything else.

     /dev/ttyD??   for callin ports
     /dev/ttylD??  corresponding callin	initial-state and lock-state devices

     /dev/cuaD??   for callout ports
     /dev/cualD??  corresponding callout initial-state and lock-state devices

     /etc/rc.serial  examples of setting the initial-state and lock-state de-

     The first question	mark in	these device names is short for	the card num-
     ber (a decimal number between 0 and 65535 inclusive).  The	second ques-
     tion mark is short	for the	port number (a letter in the range [0-9a-v]).

     You may enable extended diagnostics by defining DEBUG at the start	of the
     source file dgb.c.

     dgbX: warning: address N truncated	to M  The memory address for the
     PC/Xe's 8K	window is misaligned (it should	be on an 8K boundary) or out-
     side of the first megabyte.

     dgbX: 1st reset failed  Problems with accessing I/O port of the card,
     probably the wrong	port value is specified	in the kernel config file.

     dgbX: 2nd reset failed  Problems with hardware.

     dgbX: N[st,nd,rd,th] memory test failed  Problems with accessing the mem-
     ory of the	card, probably the wrong iomem value is	specified in the ker-
     nel config	file.

     dgbX: BIOS	start failed  Problems with starting the on-board BIOS.	 Prob-
     ably the memory addresses of the DigiBoard	overlap	with some other	device
     or	with RAM.

     dgbX: BIOS	download failed	 Problems with the on-board BIOS.  Probably
     the memory	addresses of the DigiBoard overlap with	some other device or
     with RAM.

     dgbX: FEP code download failed  Problems with downloading of the Front-
     End Processor's micro-OS.	Probably the memory addresses of the DigiBoard
     overlap with some other device or with RAM.

     dgbX: FEP/OS start	failed	Problems with starting of the Front-End	Pro-
     cessor's micro-OS.	 Probably the memory addresses of the DigiBoard	over-
     lap with some other device	or with	RAM.

     dgbX: too many ports  This	DigiBoard reports that it has more than	32
     ports.  Perhaps a hardware	problem	or the memory addresses	of the Digi-
     Board overlap with	some other device or with RAM.

     dgbX: only	N ports	are usable  The	NDGBPORTS parameter is too small and
     there is only enough space	allocated for N	ports on this card.

     dgbX: port	Y is broken  The on-board diagnostic has reported that the
     specified port has	hardware problems.

     dgbX: polling of disabled board stopped  Internal problems	in the polling
     logic of driver.

     dgbX: event queue's head or tail is wrong!	 Internal problems in the
     driver or hardware.

     dgbX: port	Y: got event on	nonexisting port  Some status changed on a
     port that is physically present but is unusable due to misconfiguration.

     dgbX: port	Y: event N mstat M lstat K  The	driver got a strange event
     from card.	 Probably this means that you have a newer card	with an	ex-
     tended list of events or some other hardware problem.

     dgbX: port	Y: overrun  Input buffer has filled up.	 Problems in polling
     logic of driver.

     dgbX: port	Y: FEP command on disabled port	 Internal problems in driver.

     dgbX: port	Y: timeout on FEP command  Problems in hardware.

     stty(1), termios(4), tty(4), comcontrol(8), MAKEDEV(8)

     The dgb driver is derived from the	sio(4) driver and the DigiBoard	driver
     from Linux	and is currently under development.

     The implementation	of sending BREAK is broken.  BREAK of fixed length of
     1/4 s is sent anyway.

     There was a bug in	implementation of select(2).  It is fixed now but not
     widely tested yet.

     There is no ditty command.	 Most of its functions (alternate pinout,
     speed up to 115200	baud, etc.) are	implemented in the driver itself.
     Some other	functions are missing.

BSD			       October 13, 1995				   BSD


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