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Projects:  Supporting Legacy Interfaces








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Legacy interfaces of personal computers are to be emulated with comparatively simple means.

Why should someone bother with vintage interfaces like ISA, PCI or even the parallel port?

  • Those interfaces are well-described and well understood.
  • Large numbers of add-on cards and peripherals are around. Some types are manufactured even today, above all PCI cards and PC/104 modules for industrial control and measurement applications.
  • In many applications, bandwidth requirements are low. Hence it is possible to emulate the interfaces with inexpensive microcontrollers.
  • To develop and bring up such  devices is a good exercise in engineering education, but it has its practical use, too:
    • One can use up existing equipment.
    • The microcontroller platform can be programmed freely, without regard to operating systems.
    • Susceptible cards and modules can be operated within an environment, which is free from the noise typical of personal computers  and consumes considerably less power.

The basic concept. The personal computer is used essentially as operator console, file server, and development system. It will be attached only if necessary. 

The projects currently under way rely on 8-bit microcontrollers.  Atmel AVR (ATmega) CPUs are used, because they are sufficiently fast and can be operated in a 5-V environment.

The next logical steps are 32-bit microcontrollers and FPGAs. For example, Freescale's Kinetis series of ARM microcontrollers supports 5V operation, too. Hence it would be an obvious choice.

An ISA host based on the PC/104 form factor:

A PCI host based on the PCI/104 form factor:







February 23, 2015

Download a research report describing how to exploit ATA as a simple low-latency embedded I/O interface.