NAME

addcom — multiplexing serial communications interface

SYNOPSIS

addcom0 at isa? port 0x108 irq 5
com* at addcom?

DESCRIPTION

The addcom driver provides support for Addonics FlexPort 8/S (and probably FlexPort 4/S) boards that multiplex together up to eight (or four) EIA RS-232C (CCITT V.28) communications interfaces.

Each addcom device is the master device for up to eight com devices. The kernel configuration specifies these com devices as slave devices of the addcom device, as shown in 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 addcom device is used to compute the base addresses for the com subdevices. The port for the interrupt multiplexing register is fixed, so it is doubtful that more than one addcom can be used in a machine.

FILES

/dev/tty??

 

SEE ALSO

com(4), intro(4), isa(4)

HISTORY

OpenBSD support for addcom devices first appeared in OpenBSD 3.0.