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.