January 24, 2000 IOAT 4

### NAME

ioat - multiplexing serial communications interface

### SYNOPSIS

For 6-port BOCA IOAT66 board:

ioat0 at isa? port 0x220 irq 5 com2 at ioat? slave ? com3 at ioat? slave ? com4 at ioat? slave ? com5 at ioat? slave ? com6 at ioat? slave ? com7 at ioat? slave ?

### DESCRIPTION

The ioat driver provides support for BOCA Research IOAT66 boards that multiplex together up to six EIA RS-232C (CCITT V.28) communications interfaces.

Each ioat device is the master device for up to six com devices. The kernel configuration specifies these com devices as slave devices of the ioat 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 ioat device is used to compute the base addresses for the com subdevices. The port for the interrupt multiplexing register is not programmable.

### FILES

```/dev/tty??`

### SEE ALSO

com(4)

### HISTORY

The ioat driver was adapted from the boca driver by Michael Richardson.