Programmable Logic

Programmable logic devices make it possible to define the functionality of a chip itself. As a result, digital systems can be developed very quickly, which can be used as prototypes for later serial products or as experimental setups for research purposes.

Logic families

At the IKR different logic families from Altera are used.

MAX7000 family

  • Product term based macro cells
  • EEPROM based (non-volatile programming)
  • 32 to 256 macro cells per chip
  • 600 to 5000 gate equivalents
  • 36 to 164 IO pins

FLEX10k family

  • Look Up Table (LUT) - based logic cells
  • SRAM-based (volatile programming)
  • 576 to 12,160 logic cells per chip
  • 10,000 to 250,000 gate equivalents
  • 134 to 470 IO pins

APEX20k family

  • Look Up Table (LUT) - based logic cells
  • SRAM based (volatile programming)
  • 1.200 to 51.840 logic cells per Chip
  • 30.000 to 1.500.000 gate equivalents
  • 128 to 808 IO pins


From the net lists that a synthesis tool creates, a "Place and Route" tool now creates the program files for that particular component. For the Altera components at the IKR the programs Quartus and Max+Puls II are used.

Experimental platforms


For sophisticated designs that are designed to be extensive and fast some programmable logic devices are required  that are quite expensive. In order to be able to use these again after the assignment in a project, an adapter board was developed at the IKR, which provides the input and output pins of the module on connectors. This adapter board is then plugged onto project specific boards.

This contains:

  • A component of the Altera FLEX10K family
  • Multipolar connectors
  • A charging circuit with Eprom for configuring the FLEX10k device
  • Sockets for quartz oscillator for variable determination of the system frequency


In order to be able to implement systems with very high clock rates, not only a faster programmable component has to be used, but the peripheral components have also to be connected in an adequate manner. For this purpose, a board has been purchased at the Institute of Communication Networks and Computer Engineering, which provides a large number of peripheral components to a fast APEX20KE module:

  • 64MB SDRAM
  • 4MB Flash memory
  • 2x 1MB Cache Memory
  • Interfaces:
    • 10/100 Mb-Ethernet
    • USB
    • IEEE 1394
    • Mouse
    • Keyboard
    • VGA port
    • RS-232
    • Printer port
  • Expansion connectors for own boards

These boards are used for study projects.

Model Processor

For the lab courses, a processor for teaching purposes was developed at the IKR. This model processor makes it possible to "look into" the individual elements of a processor and also to influence the processes in the processor itself. The system was implemented by plug-in cards, each of which forms a functional unit of the processor. The functionality of the unit is completely determined by programmable logic devices. These modules can be programmed in the lab course by oneself. On the one hand this fosters the understanding of the function of a processor and on the other hand the handling of programmable logic is deepened.

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Institute of Communication Networks and Computer Engineering

Pfaffenwaldring 47, 70569 Stuttgart

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