DR11-M general-purpose interface
The DR11-M general-purpose interface was a UNIBUS device controller which provided a pair of 16-bit parallel ports, both output-only. It was a quad format card (M7865), and used an SPC slot; it used programmed I/O.
The DR11-M is roughly an output-only version of the earlier DR11-C general device interface, but is not program compatible with the DR11-C.
Connection to the user's device is via a pair of 40-pin Berg connectors; each is controlled by a separate set of registers (identical for the two connectors).
Configuration
The device's register and interrupt vector addresses are set by a pair of DIP switches. Unusually for a UNIBUS device, its interrupt priority is also set by the switches. Both the vector and priority may be read in the Control and Status Register.
Registers
The device has two pairs of control and buffer registers, which can be configured to any four sequential word locations in the I/O page; the first DR11-M is normally configured to addresses 764000-76406:
| Register | Abbreviation | Address |
|---|---|---|
| Control and Status Register A | DRCSRA | 764000 |
| Data Buffer Register A | DBDBRA | 764002 |
| Control and Status Register B | DRCSRB | 764004 |
| Datia Buffer Register B | DBDBRB | 764006 |
