Mentec PDP-11
Encyclopedia
Mentec Limited was founded in 1978 and initially focused on the development of monitoring and control software and systems. It was a significant Digital
reseller and OEM in Ireland.
In the early 1980s it had a range of remote terminal units based on the SBC/11-21 (Falcon).
Once the J11 chip became available in 1982 Mentec commenced the design of its first PDP-11 single board computer the M70.
Mentec Computer Systems Limited was a subsidiary of Mentec Limited that developed PDP-11
processors.
Mentec Inc. was a US based subsidiary of Mentec Limited.
In 1994 Digital transferred the PDP-11 operating systems to Mentec Inc
module based on the J11 chipset incorporating on-board ECC
DRAM
, bootstrap eproms and 4 Serial lines implemented using DEC DC319 DLART chips.
It also introduced software configuration via the bootstrap which all but eliminated wire-wrap configuration.
Some late models incorporated a daughter card with a Xilinx
part which replaced the DLARTs and implemented a FIFO to prevent overruns for OEM applications.
A small number of late models incorporated an SRAM daughter card which replaced the on-board DRAM
.
re-implementation from scratch of the M100.
It was based around two Texas Instruments
TI8832 ALUs and a TI 8818 microsequencer.
One of the ALUs was used as the processor ALU while the second was used to implement the memory management unit. An Intel i960
processor was used to load the microcode, perform floating point (in IEEE format) and provide ODT
.
The 4 DLARTs of the earlier M100 were emulated on a single Xilinx
part.
All of the memory (both microcode and PDP-11 main memory) was implemented using SRAM.
While not of any significant effect in the field it suffered from the fact that it used a large number of microcode controlled drivers onto tri-state buses, which made developing microcode somwehat hazardous.
The M11 design was implemented in VHDL and fully simulated using Mentor Graphics
QuickSim II with behavioural language models for both the Q-Bus
and console UART. It ran patched versions of the Digital
PDP-11/23 CPU diagnostics on the simulator before any hardware was constructed.
was an ASIC
re-implementation of the M11. Despite being an ASIC implementation it was also fully microcoded.
Digital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...
reseller and OEM in Ireland.
In the early 1980s it had a range of remote terminal units based on the SBC/11-21 (Falcon).
Once the J11 chip became available in 1982 Mentec commenced the design of its first PDP-11 single board computer the M70.
Mentec Computer Systems Limited was a subsidiary of Mentec Limited that developed PDP-11
PDP-11
The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s, one of a succession of products in the PDP series. The PDP-11 replaced the PDP-8 in many real-time applications, although both product lines lived in parallel for more than 10 years...
processors.
Mentec Inc. was a US based subsidiary of Mentec Limited.
In 1994 Digital transferred the PDP-11 operating systems to Mentec Inc
M70
The M70 was developed between 1982 and 1984. It was a quad Q-busQ-Bus
The Q-bus was one of several bus technologies used with PDP and MicroVAX computer systems manufactured by the Digital Equipment Corporation of Maynard, Massachusetts....
module based on the J11 chipset incorporating on-board ECC
ECC
-Companies:* ECC , Education through Communication for the Community, a Japanese company* Electric Car Corporation plc, a British adapter and seller of electric cars* English China Clays, an English company-Education:...
DRAM
Dram
Dram or DRAM may refer to:As a unit of measure:* Dram , an imperial unit of mass and volume* Armenian dram, a monetary unit* Dirham, a unit of currency in several Arab nationsOther uses:...
, bootstrap eproms and 4 Serial lines implemented using DEC DC319 DLART chips.
M71
The M71 was a version of the M70 intended for process control. It provided for 1/4 or 1 M Byte of ECC DRAM, up to 1/2 MB of EPROM, 4 serial lines (DC-319 DLARTs) and two parallel ports implemented using 8255 chips. It was initially designed by Mentec for use in its own Remote Terminal Units.M80
The M80 was a further development of the M70 but using parity memory and a slightly higher clock rate.It also introduced software configuration via the bootstrap which all but eliminated wire-wrap configuration.
M100
The M100 was the last of Mentec's J11 based processor boards. It was a somewhat tidied up and faster re-design of the M90.Some late models incorporated a daughter card with a Xilinx
Xilinx
Xilinx, Inc. is a supplier of programmable logic devices. It is known for inventing the field programmable gate array and as the first semiconductor company with a fabless manufacturing model....
part which replaced the DLARTs and implemented a FIFO to prevent overruns for OEM applications.
A small number of late models incorporated an SRAM daughter card which replaced the on-board DRAM
Dram
Dram or DRAM may refer to:As a unit of measure:* Dram , an imperial unit of mass and volume* Armenian dram, a monetary unit* Dirham, a unit of currency in several Arab nationsOther uses:...
.
M11
The M11 was a microcodedMicrocode
Microcode is a layer of hardware-level instructions and/or data structures involved in the implementation of higher level machine code instructions in many computers and other processors; it resides in special high-speed memory and translates machine instructions into sequences of detailed...
re-implementation from scratch of the M100.
It was based around two Texas Instruments
Texas Instruments
Texas Instruments Inc. , widely known as TI, is an American company based in Dallas, Texas, United States, which develops and commercializes semiconductor and computer technology...
TI8832 ALUs and a TI 8818 microsequencer.
One of the ALUs was used as the processor ALU while the second was used to implement the memory management unit. An Intel i960
Intel i960
Intel's i960 was a RISC-based microprocessor design that became popular during the early 1990s as an embedded microcontroller, becoming a best-selling CPU in that field, along with the competing AMD 29000...
processor was used to load the microcode, perform floating point (in IEEE format) and provide ODT
Octal Debugging Technique
On-line Debugging Tool, or ODT, was the name of several debugger programs originally developed for DEC hardware. Various operating systems including OS/8, RT-11, RSX-11, and RSTS/E implemented ODT as did the firmware console of all of the LSI-11-family processors including the 11/03, 11/23/24,...
.
The 4 DLARTs of the earlier M100 were emulated on a single Xilinx
Xilinx
Xilinx, Inc. is a supplier of programmable logic devices. It is known for inventing the field programmable gate array and as the first semiconductor company with a fabless manufacturing model....
part.
All of the memory (both microcode and PDP-11 main memory) was implemented using SRAM.
While not of any significant effect in the field it suffered from the fact that it used a large number of microcode controlled drivers onto tri-state buses, which made developing microcode somwehat hazardous.
The M11 design was implemented in VHDL and fully simulated using Mentor Graphics
Mentor Graphics
Mentor Graphics, Inc is a US-based multinational corporation dealing in electronic design automation for electrical engineering and electronics, as of 2004, ranked third in the EDA industry it helped create...
QuickSim II with behavioural language models for both the Q-Bus
Q-Bus
The Q-bus was one of several bus technologies used with PDP and MicroVAX computer systems manufactured by the Digital Equipment Corporation of Maynard, Massachusetts....
and console UART. It ran patched versions of the Digital
Digital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...
PDP-11/23 CPU diagnostics on the simulator before any hardware was constructed.
M1
The M1was an ASIC
ASIC
ASIC may refer to:* Application-specific integrated circuit, an integrated circuit developed for a particular use, as opposed to a customised general-purpose device.* ASIC programming language, a dialect of BASIC...
re-implementation of the M11. Despite being an ASIC implementation it was also fully microcoded.