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The Model 1131 VME-to-SIB Interface provides a general purpose high speed connection between VME and other LeCroy instruments including data acquisition and high voltage systems. The front-panel port connects to LeCroy's Systems Interface Bus (SIB), a 16-bit wide parallel I/O bus with handshake. The module provides direct, simple control of instruments such as the LeCroy Model 1821 FASTBUS Segment Manager/Interface (SM/I) and Model 1445A Programmable Controller for the LeCroy 1440 High Voltage System, through their SIB port.

The 1131 interface is a standard VME 6 U x 160 mm single-width module. It includes an 8K word data memory, and an 8K word list memory which are accessible by the host VME bus. Counters and registers internal to the 1131 control the activity of the device. Up to 16 peripherals can be connected to one 1131. The 1131 is linked to the peripherals via flat ribbon cables running at 0.05 to 5 megabytes/sec.



The 1131 interface allows VME host processors to directly control external devices via the LeCroy System Interface Bus (SIB). The SIB is a 16-bit parallel data bus. The interface may be transparent to VME for single word transfers to the I/O or control registers of those devices. Alternatively, a string of commands and data can be loaded into the 1131 data memory by the VME host and transferred under the control of the 1131. When triggered with a front-panel ECL signal, the 1131 can also obtain data and store it in its data memory for later transfer to the VME CPU. Several different lists may be preloaded in the 1131. The list executed can be dependent on a trigger from the experiment.


Simple device commands are stored as a variable length list in the internal memory of the 1131. Up to 8 lists may be stored at the same time, subject to memory size limitations. Continuous list elements are delimited by a "Done" bit, which is set to one in the last command. The 1131 sends the list as fast as the external device accepts it. Each List Element contains the following information:

1. The module address (0-15)
2. The register address (0-15)
3. The type of operation (R/W)
4. 16 bits of data (if required)
5. Handshake control information
6. 1131 sequencer control bits
7. Done status

The VME program sets the address of the beginning of the list, and then the "GO" bit. Transfer of the list proceeds automati cally from that point with no further program intervention. Upon completion, the 1131 sets a status bit. This status bit remains set until cleared by writing to the internal status register.

Front-Panel Trigger

A front-panel trigger input allows the user to initiate list execution from an ECL signal such as those generated by LeCroy's ECLine Programmable Trigger Logic. A 3-bit base address is latched along with the front-panel trigger, allowing external logic to select one of 8 lists to execute.


Return of a handshake signal by the external device is required on every transfer. A hardware timeout is employed to monitor the response. Should the external device not respond the list is terminated.

Data Memory and Registers

The Data Memory of the 1131 may be used either as a buffer memory or for external device status reports. A DMA mode is provided to read a block of data from the external device to the internal data memory.

All memories, counters and registers are accessible from VME for testing and manual control. The I/O port may be directly controlled by the VME host for transparent data transfers.

Sixteen-bit and eight-bit transfers from VME are supported. VME Block Transfer mode with incrementing addresses is also supported.

Model 1821 Compatibility

Calibration and diagnosis of FASTBUS from VME systems is simplified with the 1131. The 1131 is fully compatible with the LeCroy Model 1821 SM/I. All 1821 SM/I registers can be accessed via the 1131. The DMA transfer capability of the 1131 allows the Data Memory of the Model 1821 to be transferred to VME quickly and easily. Microcode handling of the 1821 is also simplified allowing the running acquisition system to change microcode and re-execute with a single VME instruction, once the appropriate list is in place.

Model 1445A Compatibility

The user may directly control the 1440 High Voltage System from VME with the 1131 and 1445A combination. The Model 1445A High Voltage System Controller accepts ASCII commands from either its SIB or RS-232 ports. To control the 1445A

from the 1131, the ASCII values are placed in the lower 8 bits of the 16-bit field and written to register 0. Direct high-speed access of the 1445A's internal measurements is accomplished over SIB through other register addresses.

Cable Link

The 1131 connects to the Models 1821 and 1445A via the SIB implemented in a flat ribbon cable. To order, specify cable DCSIB/60-L, where L is the length in feet (50 feet maximum).


A simple adapter card, the Model ADP-SIB34/60, can be purchased separately. The ADP-SIB transforms the 1821's SM/I into the pin out of the SIB. The SIB bus provides a higher level of noise immunity and data reliability than the SM/I cable. Users may upgrade existing SM/I Bus systems to SIB at any time.



VME Device Type:
A24/D16, D08 (EO) Slave.

Base Address: Switch selectable, A23-A16.

Address Modifiers: Standard supervisory block transfer (3F). Standard supervisory data access (3D). Standard non-privileged block transfer (3B). Standard non-privileged data access (39).


Control and status.

CSR1: Next transfer address generator.

CSR2: Word counter.

CSR3: Destination address register.


PWR - Red LED indicates +5 V and -12 V present. ADR - Yellow LED blinks when module is addressed. RUN - Green LED indicates data transfer under 1131 control is in progress. ERR - Red LED indicates an error has occurred.

Trigger Input: 5 x 2 differential ECL, 112 ohm termination; pin chart.


SIB Connector:
SIB port connection, TTL levels (adapter card and cable are not included).

Device Type: Master, complete SIB control capability.

Speed: 5 Mbytes/sec, maximum (speed is cable length and slave dependent).


Operating Modes:
SIB direct, single transfer Read or Write of the SIB under VME (program) control; Local DMA, multiple transfer sequential Read or Write of the SIB under 1131 control; List, multiple transfer random Read and /or Write of multiple SIB modules.

Packaging: 6 U x 160 mm single-width VME, in conformance with VME Specification (ANSI/IEEE-1014C).

Operating Temperature: 10 to 50 C.

Storage Temperature: -30 to 85 C.

Maximum Humidity: 80% non-condensing at 30 C.

Power: 3 A at +5 V; 0.2 A at -12 V.


SIB cable, high density 60 conductor .025 flat ribbon. From the 1131 to the 1445A, 1821 or 3031. Specify length in feet.

ADP-SIB34/60: SIB to SM/I adaptor card required for the 1821.

Allocation of Address Space

CSR Bit Definitions

Address Structure

List Memory Data Structure

Data Memory Structure

Copyrightę September 1995. LeCroy is a registered trademark of LeCroy Corporation. All rights reserved. Information in this publicaction supersedes all earlier versions.