IOASIC(4) | Device Drivers Manual (alpha) | IOASIC(4)

# NAME

`ioasic` — baseboard IO control ASIC for DEC TURBOchannel systems

# SYNOPSIS

`ioasic0 at tc? slot ? offset ?`

# DESCRIPTION

The `ioasic` driver provides support for the DEC proprietary IOCTL ASIC found on DEC 3000 TURBOchannel machines.

The `ioasic` provides hardware DMA channels and interrupt support for several baseboard devices, including one asc(4) SCSI device with a scatter/gather DMA channel, an mc146818-compatible `mcclock`, an Am7930 audio device bba(4), two zs(4) dual-port serial devices, and an AMD 7990 LANCE le(4) Ethernet interface.

The `ioasic` is also used for the audio/ISDN hardware on audio-equipped TURBOchannel Alphas, where the `ioasic` hardware provides a scatter-gather DMA channel between the 16-bit device and the 32-bit `tc` DMA address space.

Support for scatter-gather DMA eliminates the need for additional copying.

# SEE ALSO

asc(4), bba(4), intro(4), le(4), zs(4)

# HISTORY

The `ioasic` driver first appeared in NetBSD 1.1, derived from DECstation boot-time configuration code in 4.4BSD.

November 2, 2017 | Debian