SBC with 256k dRAM controls 4 floppy disc drives

SBC with 256k dRAM controls 4 floppy disc drives A single-board computer has been designed around an MC68000L8 by Wormald Data Systems, UK subsidiary of Wormald International. The CPU-04 has 256 kbytes of dynamic RAM. It has space for up to ten 28-pin JEDEC devices. This provides onboard room for up to 192 kbytes of dynamic PROM or 96 bytes of static RAM. A mixture of static RAMs and EPROMs is also possible. The four serial onboard ports use Signetics 2661-2 controllers. The programmable baud rate generators give rates from 50 baud. The floppy disc controller is based on Western Digital's 2797. It controls either four 5¼-in or four 8-in floppy disc drives. The CPU-04 also has an MC6840 programmable counter/timer. It contains a VME P2 I/O interface. The board is designed on a double-height card to DIN41694 specification. Pricing for the CPU-04 depends on quantity. For up to ten boards the price is £I 3.75 each whereas the charge for 5 1 - 9 9 boards is £.11.70 each. Buyers of 1 1 - 2 4 and 2 5 - 5 0 devices will pay £I 3.05 and £12.35 respectively for each board. The price for over I00 is negotiable. A 68000-based VM E-compatible CPU card has also been produced by Wormald. The CPU-01 is an 8 MHz board with 128 kbytes of onboard dynamic RAM. Byte parity isincluded. The CPU-01 takes up to 16 ]EDEC 24-or 28-pin memory chips. This gives a maximum on board of 256 kbytes of EPROM or 128 kbytes of static RAM. Mixed configurations are also possible, provided all devices have the same number of pins. A buffered VME PI bus interface with one level of bus arbitration is provided. This may be isolated from the CPU by setting a bit in the module control register. The register also allows the module bus level to be set at 0 or 2. It provides a means of driving the onboard seven-segment display. The two RS232 serial interfaces on board are based around a Signetics SY2661 communications interface.

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This allows false start bit, parity, framing and overrun errors detection. The three-channel timer is based around an MC6840. It gives three 16-bit times. These can operate independently in continuous or singleshot modes. An optional subboard called the MMU-01 is available. This can be fitted

on the CPU-01 in place of the 68000 CPU. It provides an 8 MHz 68010 CPU and a twin 68451 memory management unit. (Wormald Data Systems Ltd,

Electron House, Mill Street, Slough, Berks SL2 5DD, UK. UK distributor: Unit-C, Dominion Way West, Broadwater, Worthing, Sussex BNI 4 8NT, UK. Tel: ('0903) 205233)

Boards link analysers to IEEE-488 systems Interfacing {o I EEE-488 instruments has been provided by Dutch firm Philips for its PM 3551 logic state/ timing analysers. The PM 8851/40 board has sockets for a hard copy printer and for a standard IEEE plug. There is also an adaptor for taking IEC 625 bus systems. The board allows full remote operation of an instrument with an I E E E-488 bus via a standard controlleG says Philips. There are three levels of operation in the remote mode. At the lowest level the user programs the bus controller using the keys on the front panel. The second level of control is on a menu basis.

Complete menus can be transferred between analyser and bus controller so that the user can modify the analyser settings. The third level of control governs the setting of the whole instrument. Data from the analyser can be conveyed to the controller for further processing. Information on the analyser screen can also be read line by line. This allows the controller to get disassembler listings as well as all instrument settings and state listings.

(Philips Test and Measuring Instruments, Pye Unicam Ltd, York Street, Cambridge CB 1 2PX, UK. Tel: (0223) 358866. Telex: 817331)

PM 3551 now uses IEEE-488

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