pcweasel(4) [netbsd man page]
PCWEASEL(4) BSD Kernel Interfaces 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 con- figure the port as com0 at ISA I/O address 0x3f8. When the PC-Weasel detects activity on the ST16550, the serial port is automatically con- nected 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. It is now produced by Middle Digital, Inc., http://www.realweasel.com/ 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. BSD
November 23, 2007 BSD
Check Out this Related Man Page
ace(7) Miscellaneous Information Manual ace(7) NAME
ace - Serial communications interface SYNOPSIS
controller ace0 at * slot ? vector aceintr DESCRIPTION
The ace serial line controller provides a serial communications interface on DEC 2000, AlphaStation, and AlphaServer platforms. The serial communications ports that are controlled by ace adhere to the RS-232 standard and can operate at rates from 50 to 115200 baud (see tty(7)). These communications ports support serial-line printers, modems, and terminals. In alternate console configurations (that is, no graphics head), the terminal to be the system console must be connected to the port that is mapped to /dev/tty00. (See ports(7) for information about mapping AlphaStation and AlphaServer port labels to device pathnames.) Cur- rently, some processors that use the ace driver limit the serial console port to 9600 baud, 8-bit, no parity and no modem support. However, some processor consoles do support baud rates other than 9600 baud and allow the use of modems as console devices. Consult your hardware documentation to determine the type of console support your system provides. The driver for the ace interface supports hardware flow control using the Request to Send (RTS) and Clear to Send (CTS) signals. When hardware flow control is enabled, the flow of input data is controlled by the RTS signal and the flow of output data is controlled by the CTS signal. If the CTS signal is off, the driver suspends output to that line until the CTS lead is reasserted. Likewise the driver turns off the RTS lead to tell the device connected to the line to stop sending data as a result of congestion on the host side. When the condi- tion clears, the driver turns on the RTS lead to tell the device to resume sending data. The DCD (carrier detect) timer value defaults to 2 seconds. This value may be changed if your modem hardware requires a different value. the change can be made in the /etc/sysconfigtab file as follows: ace: dcd_timer=n where n is the time interval in seconds, and can be set to 0 (no timeout), 1, or 2 seconds. Alternatively, you can use the sysconfig com- mand to set the same time interval option as follows: # sysconfig -r ace dcd_timer=[n] If you use the sysconfig command, the value will not be preserved when the system is rebooted. To preserve the setting, put the entry in the /etc/sysconfigtab file NOTES
If you are using the alternate system console to perform kernel debugging, you must change the kdebug entry in the /etc/remote file to use /dev/tty01; when the kernel is running in debugging mode, no other application can use the port. See Kernel Debugging for information on setting up your system for kernel debugging. RESTRICTIONS
Unless alternative specifications are stated in your system hardware documentation, data communications equipment attached to the console serial port in alternate console configurations must be set to 9600 baud, 8-bits, no parity. If a serial console is being used, /dev/tty00 cannot be opened by another process. The ace driver enforces this restriction. Baud rates greater than 38400 are not supported on the two primary serial ports on the DEC 2000 system. However, if you use an ISA serial or modem card that is capable of communicating at the higher rates, the higher rates are supported. FILES
console terminal local terminal local terminal RELATED INFORMATION
MAKEDEV(8), console(7), devio(7), modem(7), ports(7), tty(7) Kernel Debugging System Administration delim off ace(7)