COM(4) | Device Drivers Manual | COM(4) |
com
—
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
com* at clockport?
com0 at mainbus? base 0x00210fe0
com1 at mainbus? base 0x00210be0
com0 at pxaip?
com* at dio? scode ?
com* at frodo? offset ?
com* at dino?
com* at gsc?
com* at ssio?
com* at opb?
com* at ebus?
com* at obio0
com0 at intio0 addr 0xefff00 intr 240
com1 at intio0 addr 0xefff10 intr 241
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.
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.
com
driver was originally derived from the
HP9000/300 dca
driver.
The name of this driver and the constants which define the locations of the various serial ports are holdovers from DOS.
March 4, 2017 | NetBSD 9.4 |