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.