NOTE: This driver has not been ported from
4.4BSD yet.
The
dmf device provides 8 lines of asynchronous serial line support. The first two of these have full modem control. The device also provides a line printer port similar to the LP-11. Other features of the DMF-32 are not supported. During autoconfiguration, the driver examines the configuration of each DMF-32 and adjusts the interrupt vectors so that fewer vector locations are used if possible.
An optional argument
flags may be supplied with the device specification in the config file indicating that the line corresponding to bit number
i is not properly connected, and should be treated as hard-wired with carrier always present. Thus specifying ‘flags 0x04' for
dmf0 would cause line
ttyA2 to be treated in this way. Flags should be set for all lines without hardware support for modem control.
Normal I/O control parameters for individual lines are managed by
ioctl(2) calls. Line speeds may be initiated via
getty(8) and
stty(1) or may be communicated by other programs which use
ioctl(2) such as
ifconfig(8), see
tty(4).
The serial line part of the
dmf driver normally enables the input silos with a short timeout (30 milliseconds); this allows multiple characters to be received per interrupt during periods of high-speed input.
A line printer port on a
dmf is designated by a minor device number of the form 128+
n. See
MAKEDEV(8). Column and lines per page may be changed from the default 132 columns and 66 lines by encoding the number of columns in bits 8-15 of flags and the number of lines in bits 16-23. This device does not provide the fancy output canonicalization features of the
lp(4) driver.