OVERVIEW
APPLICATIONS
- Forms a dedicated Q-bus interface with a 2922 card or VME interface with a 2917 card
- Forms a dedicated PC interface with an associated 2926, 2927, 2928, or 2932 card
- Field-selectable as a main or auxiliary crate controller
- Up to eight crate controllers addressed on a single bus
- Supports DMA with 2922, 2926, and 2928 and block transfers with 2917 and 2932
- Includes a 24-bit LAM mask
- Interface connection made via a 40-wire, rear ribbon cable
- Contains RS-485 balanced-line signaling for high noise immunity
- Supports interface bus lengths up to 91 meters (300 feet)
Up to eight 3922s can be addressed on the interface bus. The crate address (0 through 7) is selected by a front-panel switch. A single 40-wire ribbon cable is connected to the computer interface card and looped-through the crate controllers. Interface bus connections are made at the rear of each 3922. The last 3922 terminates the bus. RS-485 balanced-line signaling is used on the interface bus to allow reliable operation with up to 91 meters (300 feet) of total bus length. Twisted-pair, flat-ribbon bus cable enhances data integrity The eight-bit interface bus is multiplexed for address and data transfer. Appropriate control/response signals are also included.
The 3922 supports the DMA capabilities of the 2922, 2926, 2927, and 2928 adapters. Sixteen-bit DMA data is transferred at rates up to 1 Mbyte/s for the Model 2922, and 250 kbyte/s for the 2926, 800 kbyte/s for the 2927, and 500 kbyte/s for the 2928. Block transfers are supported when interfacing to a computer with the 2917 VME adapter, 2932 Macintosh II adapter, or our newest addition: the 2915 PCI adapter.
A 24-bit LAM mask is included to simplify the host software. A Selected LAM Present causes a service request to the computer interface. A parallel poll is per formed to determine which 3922s are requesting service.
This module is configured at the factory as a main crate controller. It can be changed in the field to function as an auxiliary crate controller. An additional 40-contact, rear-panel connector is then used for the Auxiliary Controller Bus.
INTERNAL REGISTERS (N = 30)
Command Q Description F(1)A(0) RD2 On-line Reads Control/Status register F(1)A(12) RD2 On-line Reads LAM Pattern F(1)A(13) RD2 On-line Reads LAM Mask F(17)A(0) WT2 On-line Writes Control/Status register F(17)A(13) WT2 On-line Write LAM MaskNotes:
+ 6 volts 3.3 A
Weight: 1.2 kg (2 lb. 9 oz.)
Q-bus, RSX-11, and VMS are trademarks of Digital Equipment Corporation.
Macintosh II is a trademark of Apple Computer, Inc.
®IBM PC/AT and PS/2 are registered trademarks of IBM Corporation