Cobold

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COBOLD was the name of a small computer that was introduced in March 1983 by the West German magazine Elrad . It was accompanied by a series of articles as assembly instructions (issues 3, 4 and 5 1983) and was also the cornerstone for a number of other, mostly specialized, small computers, such as the CEPAC-65 (CMOS version, only one circuit board) and the SET-65 (Adapter with EPROM burner and keyboard / display for CEPAC-65), which are particularly suitable for control and development purposes. The articles and manual were written by Christian Persson .

Small computer COBOLD

The 1980s were a time when home computers grew wild. There were sometimes big differences in price and performance and almost no standards. Therefore there were some such instructions with which the hobbyist could build and expand a computer cheaply and with this learned the basics of programming. Because a standard PC, as well as a branded device, was almost unaffordable for private individuals.

In contrast to many others, the COBOLD came with a manual that was both documentation and textbook.

In the smallest expansion stage, it was already able to save programs on a cassette recorder, to offer a screen editor via a serial interface and a terminal , and to control external hardware via free port lines . This included 2 Kbytes of RAM and 16 I / O lines.

The necessary bus board and the amount of max. 48 I / O ports made the COBOLD a flexible, small computer for universal use. Then some articles (called COBOLD bits) appeared in ELRAD in the Computing Today section, from which the magazine c't later emerged.

Components

The computer consisted of a total of three circuit boards in the Eurocard format (160 * 100 mm):

A housing was not provided.

Technical specifications

The processor board was actually already the complete computer. It had space for a processor of the type 6502 in the NMOS or CMOS variant, which was then also used in the Commodore VC20 and Atari 800 XL and as the 6510 in the well-known C-64 . The system clock was 1 MHz, but could reach up to 4 MHz (with suitable components). In addition, the basic configuration level had a static RAM (SRAM) of 2 KByte size and a ROM of 4 KByte size with the operating system. This included one of up to three input / output modules of the type 6532 . This RIOT said block had 128 bytes R AM, 16 I / O ports and a plurality of T imer. The address decoder (in contrast to its contemporaries) was a PROM with which the chip select signals were generated. A clock generator (see above) could not be missing, of course, and an adaptation to different RAM / ROM types was possible via patch panels. The board had a 44-pin connector for the processor bus and a 64-pin connector (according to DIN 41612 type C) for connection to the bus board, through which all ports are led out.

The backplane already contained holes for 5 port expansions with 64-pin connector strips. However, only one had to be fitted for the processor board. There was also a voltage regulator, a cassette recorder interface for data storage and a serial connection for a terminal on one edge .

The keyboard display card contained two blocks of input keys, two blocks of LED seven-segment displays and two toggle switches.

The display part was divided into a four-digit address display and a two-digit data display. To the right of it was a toggle switch for switching off the displays and one for single step mode. Below that were 16 data keys for entering hexadecimal values ​​and on the right a block with control keys.

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