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COM(4)		       FreeBSD Kernel Interfaces Manual			COM(4)

NAME
     com -- serial communications interface

SYNOPSIS
     # com attachments
     #
     # i386
     com0 at isa? port 0x3f8 irq 4
     com1 at isa? port 0x2f8 irq 3
     com2 at isa? port 0x3e8 irq 5
     com3 at isa? port 0x2e8 irq 9
     com* at isapnp?
     com* at pcmcia?
     com* at puc?
     com* at cardbus?

     com* at addcom?
     com* at ast?
     com* at boca?
     com* at hsq?

     # alpha and amd64
     com0 at isa? port 0x3f8 irq 4
     com1 at isa? port 0x2f8 irq 3

     # armv7
     com* at fdt?

     # arm64
     com* at acpi?
     com* at fdt?

     # hppa
     com0 at gsc? offset 0x5000	irq 5
     com0 at gsc? offset 0x823000 irq 5
     com1 at gsc? offset 0x822000 irq 6
     com2 at gsc? irq 13
     com1 at dino? irq 11
     com0 at ssio? irq 4
     com1 at ssio? irq 3

     # loongson
     com* at leioc?

     # macppc
     com* at puc?
     com* at pcmcia?
     com* at cardbus?

     # octeon
     com* at fdt?

     # sgi
     com0 at macebus0 base 0x00390000 irq 5
     com1 at macebus0 base 0x00398000 irq 5
     com0 at ioc? base 0x00020178
     com1 at ioc? base 0x00020170

     # sparc64
     com* at asio?
     com* at ebus?
     com* at puc?

DESCRIPTION
     The com driver provides support for NS8250-, NS16450-, NS16550-,
     ST16650-, ST16C654-, and TI16750-based EIA	RS-232C	(CCITT V.28) communi-
     cations interfaces.

     The NS8250	and NS16450 have single	character buffers, the NS16550 has a
     16	character buffer, while	the ST16650 has	a 32 character buffer, and the
     TI16750 has a 64 character	buffer.

     Input and output for each line may	be set to one of following baud	rates;
     50, 75, 110, 134.5, 150, 300, 600,	1200, 1800, 2400, 4800,	9600, 19200,
     38400, 57600, or 115200, or any other baud	rate which is a	factor of
     115200.

FILES
     /dev/tty00
     /dev/tty01
     /dev/cua00
     /dev/cua01

DIAGNOSTICS
     com0: N silo overflows  The input "silo" has overflowed and incoming data
     has been lost.

     com0: weird interrupt: iir=XXXX  The device has generated an unexpected
     interrupt with the	code listed.

SEE ALSO
     addcom(4),	asio(4), ast(4), boca(4), cardbus(4), dino(4), ebus(4),
     gsc(4), hsq(4), intro(4), isa(4), isapnp(4), pcmcia(4), puc(4), ssio(4),
     tty(4)

HISTORY
     The com driver was	originally derived from	the HP9000/300 dca driver.

BUGS
     Data loss is possible on busy systems with	unbuffered UARTs at high
     speed.

     The name of this driver and the constants which define the	locations of
     the various serial	ports are holdovers from DOS.

FreeBSD	13.0		       January 22, 2020			  FreeBSD 13.0

NAME | SYNOPSIS | DESCRIPTION | FILES | DIAGNOSTICS | SEE ALSO | HISTORY | BUGS

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