The Model 1821 is a programmable FASTBUS module designed to provide operations on the Segment at the full speed of the standard. The device can be programmed to act as a Slave, a Master or as a Snoop. The 1821 provides two sections, the Sequencer and the Interface.
The Sequencer within 1821 operates under the control of its micro- program, executing one instruction every 33 nsec. The instructions have multiple fields, typically allowing five operations to be per- formed at once. The unit offers complete exercise of the FASTBUS protocol lines allowing any FASTBUS operation or series of operations to be programmed. The program word includes a branch operation based upon a wide variety of possible conditions including SS, MS and the data on the AD lines. This branching feature allows the Model 1821 to execute prorrams with Loops.
The Sequencer offers complete FASTBUS arbitration logic. It also provides hardware for a sparse data scan based upon the T-pins.
Data may be written to the FASTBUS AD lines either from the program word or from the Interface. Data may also be read from the AD lines and either used by the Sequencer or transmitted to the interface section. The Sequencer does not provide arithmetic operations on the data.
The Interface of the Model 1821 provides hardwired pedestal subtraction and threshold comparison. Both features can be enabled by the Host computer The Interface offers a 8K x 10 pedestal memory and a 4K x 32 data memory. Data from the Sequencer may be pipeline processed at a 10 megawords/sec rate. The information is applied at the FASTBUS Auxiliary Connector as it is loaded into the data memory. In this way, the Host can address the data memory, or datawords may be pipeline transferred out of the 1821 to another device such as the 1891 FASTBUS Multiple Event Buffer.
The Interface is connected to an intelligent Host via an interface personality card. The FASTBUS Auxiliary Connector is employed for this purpose. Personality cards allowing connection to the Model 1891 Multiple Event Buffer and to a PDPll UNIBUS Interface (DR11W) are available. A front-panel connector on the Model 1821 provides for connection to a CAMAC Interface, Model 2891. For details on interconnection, see LeCroy Application Note AN28. The 1821 may be user programmed; however, firmware within the unit allows the most common FASTBUS primitives and macros to be executed by simple calls from the Host. Many operations can be executed by a single call; however, the 1821 provides for executable lists also. Extensive firmware is provided for use with LeCroy's 1800 Series of FASTBUS data acquisition modules. In addition, to set up operating parameters and automated test of the crates, the 1821 provides ordered readout of 1800 Series ADC's, TDC's and ICA's.
The Model 1821 has four Menu PROM's, each containing a series of functionally grouped FASTBUS operations. One PROM provides crate checkout and startup operations, another contains CSR setup routines, another data acquisition, another calibra- tion. Any one of the PROM's may be loaded into the Sequencer's memory under control of the Host computer in < 1 msec. Thereafter, any of the routines in the PROM may be called and executed.
Control words transferred from the Host to the 1821 are used for setup. This allows data compaction and pedestal subtraction to be enabled, it allows Sequencer programs or firmware to be uploaded or downloaded to or from the Host or from the Menu PROM's.
SPECIFICATIONS
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CONNECTORS |
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Personality Connector: |
Uses FASTBUS Auxiliary Connector. Intended for interface to the Host. TTL logic. Provides 16-bit data field, 3-bit address and two strobes; read and write. Access time <300 nsec. Also 32-bit data in/out field presented at rates up to 10 MHz. |
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Sequencer Monitor: |
Front panel 34-pin ECL connector. Provides monitor of the operation of the Sequencer. |
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Interface Monitor: |
Front panel 34-pin header providing TTL signals to monitor the Interface. Connects directly to the 2891 CAMAC Interface. |
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IN1, IN2, IN3: |
Differential ECL inputs via 2-pin ECLine connectors. Used as real time conditions for the 1821 Sequencer. Operations depend upon software. Minimum duration 30 nsec. |
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OUT1, OUT2, OUT3: |
Differential ECL outputs via 2-pin ECLine connectors. Driven under software control. |
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GENERAL |
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Packaging: |
Standard double width FASTBUS module in conformance with FASTBUS Working Group Document dated June 9, 1982. |
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Power Requirements: |
5 A at +5V |
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Accessories: |
Model 2891: CAMAC Interface |
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Model DC4/34-m: Connecting cable for 2891; Here m is length in meters. |
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Model 1821/DEC: Personality card for the DR11W UNIBUS Interface. |