SYM-1
Encyclopedia
The SYM-1 was a single board "trainer" computer
produced by Synertek
circa 1978. Originally called the VIM-1 (Versatile Input Monitor), that name was changed for legal reasons sometime between April and August 1978.
The SYM-1 was a competitor to the popular MOS Technology
KIM-1
system, with which it was compatible to a large extent. Compared to the KIM-1
, enhancements included the ability to run on a single +5 volt power supply, an enhanced monitor ROM
, three configurable ROM/EPROM
sockets, RAM
expandable on-board to , an RS-232
serial port, and a "high speed" audio cassette storage interface. It also featured on-board buffer circuits to ease interfacing to "high voltage or high current" devices.
One rather distinctive capability of the SYM-1 was its ability to allow an oscilloscope
to be added to provide a 32 character display under software control.
Synertek sold ROMs which could be installed to add the BASIC
programming language or a Resident Assembler/Editor (RAE). Synertek contracted with a company called Eastern House Software to port their Macro Assembler/Editor (MAE) into an ROM. The author of MAE, RAE, and another version sold by Skyles Electric Works was Carl Moser. MAE was sold in various forms not only for the SYM-1 but also for other 6502-based computers including Commodore, Atari, KIM, and Apple. Other forms of MAE included a cross assembler for 6800 and 8085 -- and an offering of these cross assemblers was planned for RAE.
One of the more subtle features of the SYM-1 was the use of a look up table in the low memory of the 6502. This provided a vectoring function in its operating system to redirect subroutine calls to various input and output drivers, including interrupt servicing
. Users were able to develop their own interface routines, and substitute new vectors for the original vectors in the startup UV-EPROM. This seamlessly maintained the normal operation of the board's monitor and languages such as Synertek Systems BASIC. One of the later home/education computers that used this concept extensively was the BBC Micro
produced by Acorn Computers
in the UK. Some of the other computer designers of this era failed to grasp the significance of this elegant use of vectors to the software mapping of new developments in hardware.
Microprocessor development board
A microprocessor development board is a printed circuit board containing a microprocessor and the minimal support logic needed for an engineer to become acquainted with the microprocessor on the board, and to learn to program it...
produced by Synertek
Synertek
Synertek, Inc. was an American semiconductor manufacturer founded in 1973. The initial founding group consisted of Bob Schreiner , Dan Floyd, Zvi Grinfas, Jack Balletto, and Gunnar Wetlesen. The manufacturing technology was MOS/LSI...
circa 1978. Originally called the VIM-1 (Versatile Input Monitor), that name was changed for legal reasons sometime between April and August 1978.
The SYM-1 was a competitor to the popular MOS Technology
MOS Technology
MOS Technology, Inc., also known as CSG , was a semiconductor design and fabrication company based in Norristown, Pennsylvania, in the United States. It is most famous for its 6502 microprocessor, and various designs for Commodore International's range of home computers.-History:MOS Technology, Inc...
KIM-1
KIM-1
The KIM-1, short for Keyboard Input Monitor, was a small 6502-based single-board computer developed and produced by MOS Technology, Inc. and launched in 1976...
system, with which it was compatible to a large extent. Compared to the KIM-1
KIM-1
The KIM-1, short for Keyboard Input Monitor, was a small 6502-based single-board computer developed and produced by MOS Technology, Inc. and launched in 1976...
, enhancements included the ability to run on a single +5 volt power supply, an enhanced monitor ROM
Read-only memory
Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...
, three configurable ROM/EPROM
EPROM
An EPROM , or erasable programmable read only memory, is a type of memory chip that retains its data when its power supply is switched off. In other words, it is non-volatile. It is an array of floating-gate transistors individually programmed by an electronic device that supplies higher voltages...
sockets, RAM
Ram
-Animals:*Ram, an uncastrated male sheep*Ram cichlid, a species of freshwater fish endemic to Colombia and Venezuela-Military:*Battering ram*Ramming, a military tactic in which one vehicle runs into another...
expandable on-board to , an RS-232
RS-232
In telecommunications, RS-232 is the traditional name for a series of standards for serial binary single-ended data and control signals connecting between a DTE and a DCE . It is commonly used in computer serial ports...
serial port, and a "high speed" audio cassette storage interface. It also featured on-board buffer circuits to ease interfacing to "high voltage or high current" devices.
One rather distinctive capability of the SYM-1 was its ability to allow an oscilloscope
Oscilloscope
An oscilloscope is a type of electronic test instrument that allows observation of constantly varying signal voltages, usually as a two-dimensional graph of one or more electrical potential differences using the vertical or 'Y' axis, plotted as a function of time,...
to be added to provide a 32 character display under software control.
Synertek sold ROMs which could be installed to add the BASIC
BASIC
BASIC is a family of general-purpose, high-level programming languages whose design philosophy emphasizes ease of use - the name is an acronym from Beginner's All-purpose Symbolic Instruction Code....
programming language or a Resident Assembler/Editor (RAE). Synertek contracted with a company called Eastern House Software to port their Macro Assembler/Editor (MAE) into an ROM. The author of MAE, RAE, and another version sold by Skyles Electric Works was Carl Moser. MAE was sold in various forms not only for the SYM-1 but also for other 6502-based computers including Commodore, Atari, KIM, and Apple. Other forms of MAE included a cross assembler for 6800 and 8085 -- and an offering of these cross assemblers was planned for RAE.
One of the more subtle features of the SYM-1 was the use of a look up table in the low memory of the 6502. This provided a vectoring function in its operating system to redirect subroutine calls to various input and output drivers, including interrupt servicing
Interrupt
In computing, an interrupt is an asynchronous signal indicating the need for attention or a synchronous event in software indicating the need for a change in execution....
. Users were able to develop their own interface routines, and substitute new vectors for the original vectors in the startup UV-EPROM. This seamlessly maintained the normal operation of the board's monitor and languages such as Synertek Systems BASIC. One of the later home/education computers that used this concept extensively was the BBC Micro
BBC Micro
The BBC Microcomputer System, or BBC Micro, was a series of microcomputers and associated peripherals designed and built by Acorn Computers for the BBC Computer Literacy Project, operated by the British Broadcasting Corporation...
produced by Acorn Computers
Acorn Computers
Acorn Computers Ltd. was a British computer company established in Cambridge, England, in 1978. The company produced a number of computers which were especially popular in the UK. These included the Acorn Electron, the BBC Micro, and the Acorn Archimedes...
in the UK. Some of the other computer designers of this era failed to grasp the significance of this elegant use of vectors to the software mapping of new developments in hardware.
External links
- SYM-1 page at 6502.org
- The SYM-1 at old-computers.com
- SYM-1 and collection of old digital and analog computers at oldcomputermuseum.com
- ReactiveMicro.com - SYM-1 ROMs for download and purchase
- http://6502.org/users/dallas/ Full blown DOS on a Sym-1