RTFPS(4) BSD Kernel Interfaces Manual RTFPS(4)NAME
rtfps -- multiplexing serial communications interface
SYNOPSIS
rtfps0 at isa? port 0x1230 irq 10
com2 at rtfps0 slave 0
com3 at rtfps0 slave 1
com4 at rtfps0 slave 2
com5 at rtfps0 slave 3
DESCRIPTION
The rtfps driver provides support for IBM RT PC boards that multiplex together up to four EIA RS-232C (CCITT V.28) or RS-422A communications
interfaces.
Each rtfps device is the master device for up to four com devices. The kernel configuration specifies these com devices as slave devices of
the rtfps device, as shown in the synopsis. The port specification for the rtfps device is used to compute the base addresses for the com
subdevices.
FILES
/dev/tty0?
SEE ALSO com(4)HISTORY
The rtfps driver was written by Charles Hannum, based on the ast driver.
BUGS
The rtfps driver is unlikely to work on non-EISA and non-PCI machines. The ISA bus only asserts 10 I/O address lines, and this is not
enough.
Even on EISA and PCI machines, some address conflicts have been observed. On one machine, the second port always conflicted with something
(though it's not clear what) and caused strange results. Disabling the second port in the kernel config allowed the other three ports to
function correctly.
BSD August 7, 1994 BSD
Check Out this Related Man Page
COM(4) BSD Kernel Interfaces Manual COM(4)NAME
com -- serial communications interface for RS-232C
SYNOPSIS
com0 at isa? port "IO_COM1" irq 4
com1 at isa? port "IO_COM2" irq 3
com* at acpi?
com* at cardbus?
com* at isapnp?
com* at mca? slot ?
com* at mhzc?
com* at ofisa?
com* at pcmcia?
com* at pcmcom?
com* at pnpbios? index ?
com* at puc? port ?
com* at xirc?
options COM_HAYESP
options PPS_SYNC
options PPS_TRAILING_EDGE
options RND_COM
Arm32
com0 at mainbus? base 0x00210fe0
com1 at mainbus? base 0x00210be0
HP 9000/300 and 400 Series
com* at dio? scode ?
com* at frodo? offset ?
HP 9000/700 and 800 Series
com* at dino?
com* at gsc?
com* at ssio?
IBM PowerPC 4xx
com* at opb?
SPARC
com* at ebus?
com* at obio0
DESCRIPTION
The com driver provides support for NS8250-, NS16450-, and NS16550-based EIA RS-232C (CCITT V.28) communications interfaces. The NS8250 and
NS16450 have single character buffers, and the NS16550 has a 16 character buffer.
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 115200, or any other baud rate which is a factor of 115200.
The ttyXX devices are traditional dial-in devices; the dtyXX devices are used for dial-out. (See tty(4).)
options COM_HAYESP adds support for the Hayes ESP serial board.
options PPS_SYNC enables code to use the Data Carrier Detect (DCD) signal line for attachment to an external precision clock source (e.g.,
GPS, CDMA) which generates a Pulse Per Second (PPS) signal. This is used by ntpd(8) to discipline the system clock, and more accurately
count/measure time. See options(4) for more discussion.
With options RND_COM enabled, the com driver can be used to collect entropy for the rnd(4) entropy pool. The entropy is generated from
interrupt randomness.
Arm32 specific
If ``flags 1'' is specified, the com driver will not set the MCR_IENABLE bit on the UART. This is mainly for use on AST multiport boards,
where the MCR_IENABLE bit is used to control whether or not the devices use a shared interrupt.
FILES
/dev/dty00
/dev/dty01
/dev/dty02
/dev/tty00
/dev/tty01
/dev/tty02
DIAGNOSTICS
com%d: %d silo overflows The input ``silo'' has overflowed and incoming data has been lost.
com%d: weird interrupt: iir=%x The device has generated an unexpected interrupt with the code listed.
SEE ALSO acpi(4), ast(4), cardbus(4), isa(4), isapnp(4), mca(4), mhzc(4), ofisa(4), options(4), pcmcia(4), pcmcom(4), pnpbios(4), puc(4), rtfps(4),
tty(4), xirc(4), ntpd(8)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.
BSD June 7, 2011 BSD