The 6502 processor Eurocard (100 x 160 mm) has crystal control 1K bytes of RAM and 512 bytes PROM containing a system monitor. A second Eurocard is mounted above it using pillars the two are connected by ribbon cable. The top card has a click action 25 key hexadecimal keyboard and an eight digit seven-segment LED display.
The system monitor contained in two fusible link PROMS(74S571) is very easy to use and provides the following facilities using one of the 8154 devices as a keyboard interface and display driver. complete catalogue text.
Provides the basis for the addition of more Eurocards. The system 2 contained within a 19" card frame consists of the following Eurocards all of which are described individually in this catalogue.
6502 CPU (code 720)
This is a crystal 6502 processor card, with a 2K
byte Cassette Operating System (COS) and a keyboard interface.
VDU Interface (code 740)
- 40 column x 25 lines, 8 colours including
black and white. The COS provides drivers for display of text and graphics
and hardware scrolling.
MEM0RY BOARD (code 735)
Carries 4K bytes of RAM (a further 4K may be
added) and the 4K BASIC ROM. A second ROM containing a floating point
package and scientific functions may be added. Customers may specify
CU-MEM as an alternative to this memory card, at no extra cost.
CASSETTE INTERFACE (code 935)
Using this board, programs and data
may be stored on an audio cassette recorder.
The four boards are connected in the card frame using an 8-slot backplane with two part Eurocard DIN connectors.
Please note that a keyboard is usually required for this system. Printers and TV monitors suitable for this system are listed elsewhere in this catologue.
The system 3 in its minimum form is a system driving a single disk. The hardware consists of a card frame, backplane with 4 sockets, 6502 CPU, VDU interface, 8K RAM, floppy disk modules, DOS (Disk Operating System) and resident 4K BASIC.
The mini floppy disk drive is mounted in a 7" module together with its controller card and provides approximately 100K bytes of storage. A DOS ROM on the CPU card controls the drive and handles files and input/output eg: the parallel ASCII keyboard and memory mapped VDU.
Software may be loaded from disk or contained in ROM. All the Acorn Eurocards are compatible with this configuration, allowing enourmous variations on a modular basis. The illustration above shows the addition of a further 3 RAM cards (giving 32K bytes of memory in total) and versatile interface board.
Please note that a keyboard is usually required for this system. Printers and TV monitors suitable for this system are listed elsewhere in sections 10 and 11.
Customers may specify CU-MEM in place of Acorn 8K RAM cards for use in these systems at no extra cost.
The system 4A is housed in a double height rack with capacity for up to 14 Eurocards. The mimimum system has as standard two floppy disk drives, power supplies, card frame buffered 14 slot backplane, 6502 CPU, VDU interface, 16K RAM and disk controller. A DOS(Disk Operating System) controls both disk drives and a disk with utilities programs including disk copy is supplied with each system.
Customers may spcify U-MEM in place of the Acorn 8K RAM card at no extra cost.
The system illustrated has the additional audio cassette interface, 32K bytes of RAM and serial and parallel interfaces using the versatile interface board.
Please note that a keyboard is usually required for this system. Printers and TV monitors suitable for this system are listed elsewhere in sections 10 and 11.