NAME
ast —
multiplexing serial
communications interface
SYNOPSIS
ast0 at isa? port 0x1a0 irq 5
com2 at ast? slave ?
com3 at ast? slave ?
com4 at ast? slave ?
com5 at ast? slave ?
DESCRIPTION
The
ast driver provides support for boards that multiplex
together up to four EIA RS-232C (CCITT V.28) communications interfaces.
Apparently the original maker of hardware using this multiplexing protocol was
AST.
Each
ast device is the master device for up to four
com devices. The kernel configuration specifies these
com devices as slave devices of the
ast
device, as shown in the synopsis. The slave ID given for each
com device determines which bit in the interrupt
multiplexing register is tested to find interrupts for that device. The port
specification for the
ast device is used to compute the base
addresses for the
com subdevices and the port for the
interrupt multiplexing register.
FILES
-
-
- /dev/tty0?
-
SEE ALSO
com(4)
HISTORY
The
ast driver was written by Roland McGrath and placed into
the public domain.