Implementacja programowalnego układu czasowego w układzie Virtex-5

W pracy opisujemy implementację programowalnego układu czasowego (PTU) w układzie Virtex-5 (XL5VLX50T). Przedstawiamy zasadę działania PTU, podstawowe tryby pracy oraz przykładowe przebiegi otrzymane w tym układzie.

Programmable Time Unit (PTU) offers numerous functions of digital processing of phase, frequency and width of rectangular impulses. The mode of working of PTU and the parameters of the output signal are programmable. The conversion process starts synchronously with the input signal. In this paper we describe an implementation of the programmable time unit (PTU) in Virtex-5 (XL5VLX50T) circuit. The principle of PTU work, basic modes of work and exemplary waveforms obtained in this circuit were presented. The set of applications includes electronics, telecommunications and informatics. The set of functions available in PTU can be divided into two basic groups. The first group contains: programmable delay of an impulse slope, programmable phase shift, pulse position modulation, pulse width modulation, frequency modulation with fixed or modulated pulse width, the generation of programmable number of impulses with programmable delay of generation, and many others. The second group contains functions that require a collaboration of PTU with one or two additional circuits. They are: broad-band phase shift, fast frequency synchronization in the wide range of the input frequencies, adding or multiplication of two numbers, etc. The PTU implemented in Virtex-5 uses less than 1% of its resources. It can also be implemented in cheaper FPGA as a single, low-cost circuit for general purposes.