DR11-A General Device Interface

The DR11-A General Device Interface was a UNIBUS device controller which provided a pair of 16-bit parallel ports, one input, and one output.

It was a dual format card (M786), along with two standard single-width card FLIP CHIPs, the M105 Address Selector and the M782 Interrupt Control; they used an SPC slot.

Connection to the user's device is via a DEC backplane slot connector on one side of the card, into which two single-width paddle cards plugged.

The DR11-A was replaced by the single-board DR11-C general device interface. The DR11-C is upwardly compatible with the DR11-A for programming, but uses the cheaper and easier to work with Berg connectors.

Registers

The device has three control and buffer registers, which can be configured to any three sequential word locations in the I/O page; the first DR11-A is normally configured to addresses 777520-777524:

Register	Abbreviation	Address
Control and Status Register	DRCSR	777520
Output Buffer Register	DROUTBUF	777522
Input Buffer Register	DRINBUF	777524

In the register contents (below), bits which are read/write or unused are shown in normal font, those which are read-only are in italics.

Status Register (DRCSR)

REQ B	Unused							REQ A	INT ENB A	INT ENB B	Unused
15	14	13	12	11	10	09	08	07	06	05	04	03	02	01	00

Output Buffer Register (DROUTBUF)

OUT15 <-> OUT0
15	14	13	12	11	10	09	08	07	06	05	04	03	02	01	00

Input Buffer Register (INBUF)

IN15 <-> IN0
15	14	13	12	11	10	09	08	07	06	05	04	03	02	01	00

External links

• DR11-A General Device Interface