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PCWEASEL(4) Device Drivers Manual PCWEASEL(4)
NAME
pcweasel - Support for the PC-Weasel serial console board
SYNOPSIS
pseudo-device pcweasel
weasel* at pci? dev ? function ?
Note that the appropriate display device must also be enabled. See
pcdisplay(4) for more information.
DESCRIPTION
The PC-Weasel is a serial console board for use primarily on Intel-based
PC-class systems. It addresses a problem that nearly everyone who has
deployed a PC-class server has experienced: the total lack of remote
management capability on PC-class hardware.
In addition to serial console support, the PC-Weasel provides the ability
to remotely reset the system (by means of a hardware reset signal), and
provides a watchdog timer function.
The PC-Weasel works by emulating the original IBM Monochrome Display
Adapter (MDA). Writes to the display's character cells are translated
into ANSI terminal sequences which are then sent out the PC-Weasel's
serial port. Incoming characters are translated into PC keyboard scan
codes and then fed (by means of a cable) into the system's keyboard
controller. The system believes it is using a display console. This is
particularly important in the event that one needs access to BIOS
configuration menus.
The PC-Weasel also includes a ST16550 serial port, which may be
configured as any one of the system's serial ports. Typical usage is to
configure the port as com0 at ISA I/O address 0x3f8. When the PC-Weasel
detects activity on the ST16550, the serial port is automatically
connected to the ST16550 so that the serial port may be used as normal.
When the PC-Weasel detects activity on the internal UART used for MDA
emulation, the serial port is automatically reconnected to the emulation
UART. This allows the boot program and kernel to be configured to use
the serial port directly (which is more efficient than using the MDA
emulation mode), yet allows the MDA emulation to be reestablished as soon
as the kernel loses control of the system.
The pcweasel driver provides support for the additional features present
on the PC-Weasel. At the moment, this includes support for the watchdog
timer function. Use of the pcweasel driver is not required in order for
the system to function with a PC-Weasel installed so long as only the MDA
emulation and ST16550 serial port functionality is required.
SEE ALSO
pcdisplay(4), wdogctl(8)
HISTORY
The pcweasel driver first appeared in NetBSD 1.5.1.
AUTHORS
The PC-Weasel was invented by Herb Peyerl and Jonathan Levine at Canada
Connect Corporation.
The pcweasel driver was written by Jason R. Thorpe <thorpej@zembu.com>,
and contributed by Zembu Labs, Inc. Herb Peyerl of Middle Digital, Inc.
provided several firmware updates during the development of the driver.
NetBSD 10.99 November 23, 2007 NetBSD 10.99