LRT links M ultibus into Ethemet A communications controller for connecting Multibus (IEEE 796) systems into Ethernet has been designed by UK firm Logic Replace- ment Technology (LRT).

Filtabyte 23.0 provides DMA transfer of data with programmable byte ordering. The accompanying driver software 'for most popular networking packages' cuts out overhead on the Multibus bus, says LRT. This overhead is normally associated with processing Ether- net packet data at I0 Mbyte s - I .

The LRT controller is based on a standard Multibus card. This con- tains the controller chip. Buffer management, address recognition, backoff generation and error detec- tion under hardware control are also provided.

Handling serial-to-parallel and parallel-to-serial conversion, Filta- byte 23.0 gives access to up to 128 receive and 128 transmit buffers,

framing of packets, encoding and decoding, address recognition, retransmission after collision and runt filtering.

The controller has an interrupt mode of operation. The interrupts link is selectable for packet avail- able, transmission complete, initialization complete, transmitter overruns, missed packet and memory error.

It is also possible to have a system reset presented to the Multibus host machine from the network, says LRT. The function to select for this is called EtherReset.

LRT claims that the design of Filtabyte 23.0 allows its nucleus to be used as the basis for Ethernet controllers for other computer buses as well as Multibus. (Logic Replacement Technology Ltd, 7 Arkwright Road, Reading, Berks RC2 0LU, UK. Tel: (0734) 751087. Telex: 847395)

SBC allows bus choice

A single-board 68010-based computer compatible with Multi- bus and Intel's LBX+bus has been announced by UK firm Data Design Techniques.

Standard onboard memory of the DBC68K2 is 512k using 256k RAM chips. All RAM is dual ported to Multibus. RAM can be expanded to either 1 Mbyte or 2 Mbyte by using a Microbar EXP- RAM module. Alternatively RAM can be increased by using a 512k error checking/correcting (ECC) module. This gives a total of 1 Mbyte of memory with 2-bit error detection and 1-bit error correc- tion.

The DBC68K2 has four (P)ROM/ RAM sockets for local memory or firmware. There are 18 levels of interrupt capability with support for bus-vectored interrupts. The two RS232C ports have programm- able baud rates. Two 16-bit programmable timers are also included.

The LBX+bus is capable of 8-, 16- and 32-bit data transfer. It

incorporates asynchronous bus arbitration and allows for a secon- dary master to share the bus.

Data Design Techniques will supply Uniplus-l- software to run on the DBC68K2. This is derived from Unix system III and also provides c shell, visual editor and I/O drivers. Drivers can be obtained for disc drives, printer and additional RS232C ports. (Data Design Tech- niques Ltd, 68-70 Tewin Road, Welwyn Garden City, Herts AL7 1BD, UK. Te l : (07073) 34774. Telex: 291497)

Nat Semi launches maths/ CMOS board

A mathematical processor board, in 2 MHzor4 MHz versions, has been launched by National Semiconduc- tor. The CLM-550 and CIM-551 are made in microCMOS, Nat Semi's proprietary CMOS process, and support power switching under CPU control.

The CIM-550 contains an Am9511 maths processor chip (made by Advanced Micro Devices). This carries out trans- cendental functions such as trigonometry and logarithms much faster than a microprocessor, says Nat Semi. Thus the board is targetted at maths-intensive applications, eg robotics, industrial control systems running proportional integral derivative loops, test stands and portable analysers.

Both the CIM-550 and the CIM- 551 are made in various tempera- ture versions, for commercial and other uses. All versions use the single-width Eurocard form factor.

The boards belong to the CIM (CMOS industrial microcomputer) family. This includes boards for functions such as CPU, memory expansion and digital and analogue I/O. Hence the CIM-550 and CIM- 551 operate under Nat Semi's BLMX-80C operating system and are compatible with the CIMbus board interconnection scheme. (National Semiconductor, Industrie- strasse 10, D-8080 Fursten- feldbruck, FRG. Tel: (08141) 103376 Telex: 527649)

16-line multiplexer is Q-bus compatible A communications multiplexer has been produced by US firm Grant Technology Systems. Compatible with the Digital Equipment Q-bus, the model 309 is a dual-height board with up to 1 6 asynchronous serial lines.

The multiplexer provides exten- ded 22-bit addressing, four-level interrupt and an onboard DMA controller. The 192-character receiver buffer is of the first-in-first- out type.

Multiple local or remote terminals and peripherals can be connected via the multiplexer at data rates of up to 38.4 kbaud using RS232C or CCITT V.24 interface systems, says UK distributor Amplicon. (Grant Technology Systems Corp., 11 Summer Street, Chelmsford, MA 01824, USA. UK distributor: Amplicon Electronics Ltd, Rich- mond Road, Brighton, East Sussex BN2 3RL, UK. Tel: (0273) 608331. Telex: 877470 AMPCON G)

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