lpt(4)
NAME
lpt - generic printer device driver
SYNOPSIS
device ppc device ppbus device lpt
DESCRIPTION
- The current lpt driver is the port of the original lpt driv
- er to the
ppbus(4) system. - One purpose of this port was to allow parallel port sharing
- with other
parallel devices. Secondly, inb()/outb() calls have been - replaced by
ppbus function calls. lpt is now arch-independent thanks to - the ppbus
interface. See ppbus(4) for more info about the ppbus sys - tem.
- The parallel port bus is allocated by lpt when the printer
- device is
opened and released only when the transfer is completed: ei - ther when the
device is closed or when the entire buffer is sent in inter - rupt driven
mode. - The driver can be configured to be either interrupt-driven,
- or to poll
the printer. Ports that are configured to be interrupt - driven can be
switched to polled mode by using the lptcontrol(8) command. - Depending on your hardware, extended capabilities may be
- configured with
the lptcontrol(8) command. With an ECP/ISA port, you can - take advantage
of FIFO and DMA. - In order to retrieve printer info from /dev/lpt0, just apply
- the cat command to the device. If the printer supports IEEE1284 nibble
- mode and has
data to send to the host, you will get it.
FILES
/dev/lpt0 first parallel port driver
SEE ALSO
ppbus(4), ppc(4), lptcontrol(8)
HISTORY
- This driver replaces the functionality of the lpa driver,
- which is now
defunct.
BUGS
- There are lots of them, especially in cheap parallel port
- implementations.
- It is only possible to open a lpt port when a printer is
- connected and
on-line, making it impossible to run lptcontrol(8) when - there is no
printer connected. - This driver could still stand a rewrite.
- BSD February 14, 1999