---
name: "asp"
section: "4"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["openbsd"]
url: "https://new.carta.tech/asp/4"
---

# asp(4)

core bus controller as present on older HP 9000/700 machines

## NAME

**asp** – core bus controller as present on older HP 9000/700 machines

## SYNOPSIS

**asp0    at mainbus? irq 28** **gsc\* at asp?**

## DESCRIPTION

The supported Core bus controllers are those present on older PA-RISC workstations, and include:

- Core bus controller

- System clock

- Interrupt controller

- DMA controller

- Real-time clock Interface

- RAM and EEPROM controllers

The irq level supplied is hardwired to the CPU pin, so changing the value would not produce any noticeable results (except lost interrupts for the whole I/O subsystem).

## MACHINES

An incomplete list of machines that use the ASP bus controller:

- 705, 710

- 715/{33,50,75}

- 725/{50,75}

- 720, 730, 750

- 735/\*

- 745i/{50,75}

- 747i/{50,75}

- 755/\*

## SEE ALSO

[gsc(4)](/gsc/4.md), [intro(4)](/intro/4.md), [io(4)](/io/4.md) *Hardball I/O Subsystem ERS*, Revision 1.1, Hewlett-Packard, 30 September 1991.

## HISTORY

The **asp** driver appeared in OpenBSD 2.4.