dhu(4) - NetBSD Manual Pages

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DHU(4)                NetBSD/vax Kernel Interfaces Manual               DHU(4)


NAME
dhu -- DHU-11/DHV-11 serial communications multiplexer
SYNOPSIS
dhu0 at uba0 csr 0160440
DESCRIPTION
A DHU-11 provides 16 communication lines. Normal I/O control parameters for individual lines are managed by ioctl(2) calls. Individual DHU-11 lines may be configured to run at any of 13 speeds (50, 200 and 38400 baud are not available); the speed may be set via getty(8) or stty(1) or may be communicated by other programs which use ioctl(2) such as ifconfig(8), see tty(4). The DHU-11 driver normally uses input silos and delays receiver inter- rupts by 20 milliseconds rather than taking an interrupt on each input character.
FILES
/dev/tty[S-Z][0-9a-f]
NOTES
The driver currently does not make full use of the hardware capabilities of the DHU-11, for dealing with XON/XOFF flow-control or hard-wired lines for example. Although the devices are not the same, a DHU-11 can convince the DH-11 autoconfiguration code that it is a DH-11. The 4 40-way cables are a pain.
SEE ALSO
tty(4)
HISTORY
The dhu driver appeared in 4.3BSD. A new dhu driver showed up in NetBSD 1.2.
BUGS
Even if the dhu hardware supports DMA, the driver cannot make use of this capability. NetBSD 9.0 June 5, 1993 NetBSD 9.0
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