1 .\" $NetBSD: pcweasel.4,v 1.4 2007/11/23 11:40:50 xtraeme Exp $
3 .\" Copyright (c) 2000 Zembu Labs, Inc.
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6 .\" Author: Jason R. Thorpe <thorpej@zembu.com>
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39 .Nd Support for the PC-Weasel serial console board
41 .Cd "pseudo-device pcweasel"
42 .Cd "weasel* at pci? dev ? function ?"
44 Note that the appropriate display device must also be enabled.
49 The PC-Weasel is a serial console board for use primarily on
50 Intel-based PC-class systems.
51 It addresses a problem that nearly everyone who has deployed a
52 PC-class server has experienced: the total lack of remote management
53 capability on PC-class hardware.
55 In addition to serial console support, the PC-Weasel provides the
56 ability to remotely reset the system (by means of a hardware reset
57 signal), and provides a watchdog timer function.
59 The PC-Weasel works by emulating the original IBM Monochrome
60 Display Adapter (MDA).
61 Writes to the display's character cells are translated into ANSI
62 terminal sequences which are then sent out the PC-Weasel's serial
64 Incoming characters are translated into PC keyboard scan codes and
65 then fed (by means of a cable) into the system's keyboard controller.
66 The system believes it is using a display console.
67 This is particularly important in the event that one needs access
68 to BIOS configuration menus.
70 The PC-Weasel also includes a ST16550 serial port, which may
71 be configured as any one of the system's serial ports.
72 Typical usage is to configure the port as
74 at ISA I/O address 0x3f8.
75 When the PC-Weasel detects activity on the ST16550, the serial port
76 is automatically connected to the ST16550 so that the serial port
77 may be used as normal.
78 When the PC-Weasel detects activity on the internal UART used for
79 MDA emulation, the serial port is automatically reconnected to the
81 This allows the boot program and kernel to be configured to use
82 the serial port directly (which is more efficient than using the
83 MDA emulation mode), yet allows the MDA emulation to be reestablished
84 as soon as the kernel loses control of the system.
88 driver provides support for the additional features present on
90 At the moment, this includes support for the watchdog timer function.
93 driver is not required in order for the system to function with
94 a PC-Weasel installed so long as only the MDA emulation and
95 ST16550 serial port functionality is required.
102 driver first appeared in
105 The PC-Weasel was invented by Herb Peyerl and Jonathan Levine
106 at Canada Connect Corporation.
107 It is now produced by Middle Digital, Inc., http://www.realweasel.com/
111 driver was written by
113 .Aq thorpej@zembu.com ,
114 and contributed by Zembu Labs, Inc.
115 Herb Peyerl of Middle Digital, Inc.
116 provided several firmware updates during the
117 development of the driver.