DR(4)							     Kernel Interfaces Manual							     DR(4)

NAME

       dr - DR11-W general purpose interface driver

SYNOPSIS

       /sys/conf/SYSTEM:
	    NDR  dr11-w_units	# DR11-W

       /etc/dtab:
	    #Name Unit# Addr   Vector Br Handler(s)	 # Comments
	    dr	  ?	172410 124    5  drintr 	 # dr11-w (b-bus emulator)
	    dr	  ?	172430 130    5  drintr 	 # dr11-w (gc-bus emulator)
	    dr	  ?	172450 134    5  drintr 	 # dr11-w (em-2 interface)

       major device number(s):
	    raw: 12
       minor device encoding:
	    bits 0007 specify DR unit

DESCRIPTION

       The Digital Equipment 1981-82 Peripherals Handbook states the following about the DR11-W:

	      The The DR11-W is a general purpose, direct memory access (DMA) interface to the PDP-11 UNIBUS or VAX UNIBUS.  The DR11-W moves data
	      directly between memory and the UNIBUS to and from the user's peripheral.

	      It features:

	      o      Word or byte transfers.

	      o      Programmed or direct memory access (DMA) block transfers.

	      o      Burst data transfers.

	      o      User-controlled transfer rates up to memory speed.

	      The DR11-W is a 53-line direct memory access (DMA) interface to the PDP-11 UNIBUS or VAX UBA, which allows the user to control  data
	      transfers  between the host processor and a peripheral.  The DR11-W has 32 data lines (for transferring 16-bit parallel data) and 21
	      control lines (for transferring control and status information.

	      When used as an interprocessor buffer (IPB), the DR11-W allows data transfers between two processors.  Interprocessor  communication
	      is accomplished by attaching one DR11-W to each processor UNIBUS or UBA and then cabling the two DR11-Ws together.

       There.  Now you know as much about it as I do.

       A number of ioctl(2) calls apply to the dr devices, and have the form
	      #include <pdpuba/drreg.h>
	      ioctl(fildes, code, arg)
	      int *arg;
       The applicable codes are:

       DRGTTY		 Get DR11-W status.

       DRSTTY		 Set flags and function.

       DRSFUN		 Set function.

       DRSFLAG		 Set flags.

       DRGCSR		 Get CSR and WCR.

       DRSSIG		 Set signal for ATTN interrupt.

       DRESET		 Reset DR11-W interface.

       DRSTIME		 Set timeout.

       DRCTIME		 Set timeout inactive.

       DROUTPUT 	 Put word in output data register.

       DRINPUT		 Get word from input data register.

       DRITIME		 Don't ignore errors on timeout.

FILES

       /dev/dr[0-7]	   device special files
       /dev/MAKEDEV	   script to create special files
       /dev/MAKEDEV.local  script to localize special files

SEE ALSO

       dtab(5), autoconfig(8)

DIAGNOSTICS

       dr%d: error csr=%b, eir=%b

       dr%d: timeout error

BUGS

       This interface is only available under 2.9BSD and 2.11BSD.  No documentation exists on how to use it.

3rd Berkeley Distribution					 January 27, 1996							     DR(4)