DRV11-J High-Density Parallel Interface

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DRV11-J board

The DRV11-J High-Density Parallel Interface was a QBUS parallel interface device controller which provided four bi-directional 16-bit parallel ports. It was a dual format card (M8049). It used programmed I/O; the direction of each port was programmable. It was not program compatible with any other DEC parallel port controller.

Connection to the user's device was via a pair of 50-pin Berg connectors; PORTS A and B through the bottom connector (furthest from the insertion handles), ports C an D via the top. Data going out to the user's device was latched in the DRV11-J, so may be read at leisure; data coming in from the user's device was merely sampled by the DRV11-J, so must be held until it has been read.


The device had four pairs of control and buffer registers, which could be configured to any eight sequential word locations in the I/O page. The first DRV11-J was normally configured to addresses 764160-764176; the second to 764140-767756, the third to 764120-767736, and so on.

Register Abbreviation Address
Control and Status Register A DRCSRA 764160
Data Buffer Register A DRDBRA 764162
Control and Status Register B DRCSRB 764164
Data Buffer Register B DRDBRB 764166
Control and Status Register C DRCSRC 764170
Data Buffer Register C DRDBRC 764172
Control and Status Register D DRCSRD 764174
Data Buffer Register D DRDBRD 764176

See also